Geologie en Mijnbouw portal

Content 1961 – 2004


TitleYearAuthorsVol (No)Abstract
The central alteration body of the Casapalca mines, Peru1961Overweel, C.J.40(1)The Casapalca mining district in central Peru is a source of lead, zinc, silver and copper ores of the lepthothermal type. In the centre of the mine in the single zone of the most conspicuous parallel vein system a body of rock has been intersected that does not fit in the stratigraphical sequence. Various opinions about the origin have been brought forward. The results of a systematical thin-slide study of the rock type under discussion are in favour of alteration. The coincidence of ore shoots and alteration body with certain structural elements of the Casapalca anticlinorium is discussed.
Heavy residues of some Egyptian soils1961Khadr, M.40(1)The size-distribution analyses and the heavy mineral analyses of seventeen surface samples have been studied. The results are given in Figures 1-7. An outline is liven of the most important means of sediment transport and deposition in the Nile-Valley. Under normal conditions transport of sediment in the channel is directed largely towards the sea. Only during floods and owing to the systems of irrigation practiced are sediments supplied to the soils. The coarser fluviatile sediments are especially well defined in this area by granulometric analyses. Seven types (C 1-2-3, F 4-8) are distinguished, according to the distribution of grain size, to which all the sediments in the fluviatile environments could be allocated. It appears that, in the Nile environment, all types may be represented' The heavy mineral analyses of all the samples have been formulated in Table 2. Except sample no. 31 and no. 10, no qualitative variations of the main mineral species occur and quantitative variations are not significant. One mineral association, viz. Augite-hornblende-epidote association is proposed.
A palaeomagnetic study of the Permian volcanics in the Nahe region (SW. Germany)1961Nijenhuis, G.H.W.40(1)Two magnetic poles are determined for the lower Middle Permian based on measurements of 57 rock samples taken from two lava flows in the Permian volcanic series of the Nahe region in SW. Germany. The use of the palaeomagnetic measurements for tectonical analysis is demonstrated. It is emphasized that ,,magnetical cleaning" should always be applied, in order to remove younger induced magnetic orientations.
Kort verslag van het 21e internationaal geologisch congres, Kopenhagen 15-25 augustus 19601961Koeningswald, G.H.R. von40(1)
Rheo-ignimbrite of the Ramnes volcano, Permian, Oslo graben1961Rutten, M.G.; Everdingen, R.O. van40(2)The Ramnes structure lies within the Permian igneous rocks of the Oslo Graben, west of Tönsberg. A granular inner oval of kjelsåsite is surrounded by porphyric rocks of a more acid composition. Originally interpreted as a laccolite with its acid marginal facies, we think it is a cross section through an ignimbritic volcano. The potphyritic mantle is formed by former ignimbrite fluidised tuff flows, and shows rheo-ignimbritic structures. The core is formed by the crater filling, which melted when the eruption stopped and then recrystallised as a granular rock. The difference in chemical composition between core and mantle rocks is thought to be due to selective degassing during eruption.
Zircons of some metamorphic and intrusive rocks from the aston- and hospitalet massifs (central Pyrenees)1961Verspyck, G.W.40(2)It is believed that the shape of zircon gives valuable information on the origin of metamorphic rocks; therefore several rocks have been examined on the habit of their zircons. Intrusive granodiorites and two types of metamorphic rocks all have different zircon. Several ways of representing the different observations have been used. The results of this study do not contradict the data compiled before, but form a valuable complement. Migmatites and quartzdiorites seem to have originated from a, possibly pelitic, sediment. Leucocratic gneisses possibly originated from a more sandy sediment.
Some arched and spiral structures in sediments1961Kuenen, P.H.40(2)It is argued that certain small structures described by Carozzi from sedimentary rocks are not produced mechanically by compaction and slumping, as he suggests, but result from burrowing and, or coprolites.
Het resultaat van een palynologisch onderzoek van een Eemien-afzetting bij Liessel (N.-Br)1961Mente, A.40(2)Palynological investigations by Florschütz and mrs. Anker-van Someren (1956), established a scheme and zone-division for deposits of Eemian-age in the southeastern Netherlands. These results have been obtained from analysis of samples gathered in various localities. The recent discovery of almost the complete zonation of the same scheme, this time however being the result of the analysis of a continuous series of examples coming from one boring, strongly confirmed the picture of Eemian-deposits, as revealed by Florschütz and mrs. Anker-van Someren.
Remarks on the tectonic position of the betic of Málaga in SE Spain and on its relation to the subbetic1961Booy, T. de; Egeler, C.G.40(2)
Geologisch en mijnbouwkundig nieuws196140(2)
Ten geleide, speciale uitgave veiligheid in de mijnen1961Raedts, C.E.P.M.40(3)
De ontwikkeling van wettelijke regelingen betreffende de veiligheid, de arbeid en de gezondheid in de Nederlandse mijnindustrie1961Martens, A.H.W.; Geven, J.L.40(3)
Het Nederlandse staatstoezicht op de mijnen en zijn gezagsdragers1961Raedts, C.E.P.M.40(3)
Taak en werkwijze van de veiligheidsdienst van de staatsmijnen in Limburg1961Dresen, J.P.A.40(3)
Werkzaamheden van het centraal proefstation van de staatsmijnen ten behoeve van de veiligheid en hygiëne1961Braaf, W. de40(3)
Gezondheidszorg in het bedrijf1961Mey, A.V.M.40(3)
Het staatstoezicht op de mijnen en het stofvraagstuk in de mijnen 1961Matla, W.P.M.40(3)
Het reddingswezen bij de Limburgse steenkolenmijnen1961Roos, G.40(3)
De veiligheid in het olie- en gaswinningsbedrijf1961Asselbergs, J.40(3)
Deep or not deep, fore-deep or "after-deep"1961Gillavry, H.J.M.40(4)This anniversary address discusses the history and situation of some geosynclines of intermediate type which do not fit into the standard Classification presented by Aubouin. Such intermediate geosynclines are not uncommon and their analysis leads to conclusions of more general significance. The discussion is primarily based upon the geology of the upper Paleozoic of the Baixo Alemtejo province (southern Portugal) and of the province of Huelva (southwest Spain). A comparison is made with the upper Paleozoic of the Rheinische Schiefergebirge, with the Cretaceous of Curaçao, and with the Ordovician-silurian of Wales and England. The acid rocks of the Alemtejo-HueIva area are initial volcanics of uppermost Devonian or lowermost Carboniferous age. They are not synorogenic intrusions as has often been thought. They are associated with radiolarites, and comprise rhyolitic rocks, keratophytes, spilites and diabases. The acid rocks predominate. and no serpentine has been found. The manganese and pyrite ores are thought to be primarily connected with the initial volcanism. It is suggested that the sea 'was shallow during the phase of submarine volcanism' This phase would thus not represent a periode de vacuité as conceived by Aubouin. During a later phase part of the original shallow basin would have subsided, another part would have been raised. Since volcanism has ceased by this time, it is thought that these movements are caused by compressional forces, whereas tensional forces would have reigned during the phase of volcanism' In the subsiding part of the area greywacke deposition took place; the phase of graywacke deposition is thus a phase of subsidence and not a période de comblement. The detritus in the graywackes is not derived from a pre-existing ridge or borderland, but from the rising part of the previous basin, and consists largely of rocks deposited during the preceding phase (radiolarite, rhyolite, keratophyre and spilite). This implies a flank supply, as also suggested by the presence of slump channels and intercalated conglomerates. The frequently observed occurrence of the radiolarite-ophiolite association as detritus in subsequent graywackes is an additional argument for a shallow-water deposition of this association in such cases. Disposition, facies distribution and direction of folding are the reverse of the situation usually considered as normal, and are not in favour of the theory of a continent growing through the successive addition of marginal geosynclines. The area contrasts sharply with the meseta to the north of it, the meseta proper. It is thought that the meseta proper is separated from the Alemtejo-Huelva province by a tectonic contact of the first order. An attempt to determine a minimum depth for graywacke deposition by means of a sequential analysis upwards from a reputed erosional hiatus of Tournaisian age fails, because such a hiatus could not be found. Conodonts found near Mertola suggest that Tournaisian sediments are present.
The skew frequency-curve of some ore minerals1961Agterberg, F.P.40(4)This paper deals with the following subjects: A - The theoretical meaning of the lognormal distribution of some ore minerals. B- The connection between sampling distance and frequency-curve, C - A discussion of the theory of de Wijs on the skew frequency-curves in ore assays. D - The variation of the mean concentration within an ore deposit, A - In statistics normal distribution often occurs. If x represents the concentration of a component in a certain rock, z = In x is sometimes normally distributed for this component. If we assume that the gradual addition of a certain constituent to a rock is proportional to its existing concentration, this lognormal distribution of x is to be expected. B - The mutual dependence of adjacent samples can be determined in an exact way by the determination of correlation coefficients. As this dependence gradually diminishes with the distance we can introduce the concept of the independent cell distance. The size of an independent cell is defined in such a way that its deviation from the mean concentration of all samples together is only negligibly dependent on the concentration of the adjacent cells. If the ratio between independent ceil distance and sampling distance is called a, we find that in the case a ≥ 1 the histogram resembles the curve of the lognormal distribution. In the case of stoping units with a < 1 another frequency-curve appears the shape of which can be approximated by a lognormal frequency-curve with a smaller dispersion, as found by Krige. C - It is demonstrated that de Wijs's theory of repeating division into halves of an ore deposit, while the parameter d remains constant, is not an explanation for the skew frequency-curves of ore minerals. If this d was constant, it would not mean that the distribution of the samples equals a lognormal or a logarithmic binomial curve, but only that the curve showing the variation of the mean concentration within the deposit would have a logarithmic binomial shape. The parameter d is used for an analysis of the logarithmic binomial distribution. D- Gramberg called attention to the variations of the mean concentration within an ore deposit. We propose to find this variation by, means of Fourier analysis after a preliminary drawing of the variation curve by approximation. In this way the principle of a probably gradually varying mean is maintained. When the variations of the mean are great, the skewness of the frequency-curve may be caused by the positive correlation between the mean concentration and the dispersion in a certain place. For the correlation coefficient (r) probably holds r = 1. When the dispersion around the mean is about the same in ail places of the deposit, we show that a lognormal distribution of the varying men concentration is sometimes probable.
Nordic boulders in Pre-Holtstein sediments in the netherlands (Complex of Hattem)1961Lüttig, G.W.; Maarleveld, G.C.40(4)In the region of Hattem, Nijverdal and Lemele (southeast of the IJssel-sea) coarse sands have been found in a buckled position. These sands are without bedding and carry Nordic boulders. With certainty they are older than the Holstein Interglacial, they belong to the formation of the ,,white sands" – probably to the sediments of the type Noord-Nederland (zone of Enschede) - which are assigned by many research workers at least to the Elster-age. The material of the gravel fraction as far as there is no influence of the river Rhine, comes from the Weser basin. Extraordinary is that the composition of the nordic boulder mass has values that the opposite to those hitherto stated for sediments of the pre-Saale glacial epoch. Not the east fennoskandian province of the key boulders is strongly represented but the south suedish. In connection with this determination attention is drawn to the fact that, up to the present, the assignment of the Netherland glacial sediments to the pre-Saale (Riss) is based solely on the predominance of the east fennoskandian boulders. The bedding complex did not allow to classify these sediments stratigraphically. We nominate these newly discovered boulder horizons in which, for the first time in the Netherlands, coarse, nordic material has been proved before the Hoistein stage, the ,,Complex of Hattem".
Het voorkomen van schuifstenen in de duinen196140(4)
Late Cretaceous and Tertiary stratigraphy and tectogenesis of the Colombian Andes. 1961Hammen, T. van der 40(5)This article deals with the general results of a study of the Upper Cretaceous and Tertiary of the Colombian Andes. A number (maximum 10) of rather constant and important sandstone (or conglomerate) horizons may be-distinguished, which are often excellent guide horizons. The bases of these sandstones approximately coincide with the limits of periods and epochs, but are situated in general at least several metres higher than the palynological time-limits (based on climatic changes), The constant sandstones are related to tectonic-orogenetic phases. A group of pre-andean phases (Lower and Middle Eocene), a- proto-andean phase (Upper Oligocene) and a group of eu-andean phases (Miocene and Pliocene) can be-distinguished. The Tertiary (mainly terrestrial) sedimentation as a whole representing the continuation and termination of the (mainly marine) Cretaceous geosynclinal sedimentation, may be defined as synorogenetic.
Late Cretaceous and Tertiary stratigraphy and tectogenesis of the Colombian Andes. 1961Hammen, T. van der 40(5)Plate (I)
Late Cretaceous and Tertiary stratigraphy and tectogenesis of the Colombian Andes. 1961Hammen, T. van der 40(5)Plate (II)
Late Cretaceous and Tertiary stratigraphy and tectogenesis of the Colombian Andes. 1961Hammen, T. van der 40(5)Plate (III)
Viridine, a rare constituent of Pleistocene sands1961Crommelin, R.D.; Plas, L. van der40(5)The heavy fraction of some sandy deposits in the Netherlands contains conspicuous crystals of a remarkable pleochroism ranging from golden yellow to emerald green. The optical properties might indicate at first sight the presence of a member of the epidote group. In all of 9 cases observed, however, this mineral has proved to be viridine, a manganian andalusite. Its optical properties are described and the X-ray powder pattern is given. Possible source localities are indicated.
Barnsteen1961Faber, F.J.40(5)
#REF!196140(5)Jaarverslag KNGMG 1960
The occurrence of Betic of Málaga in the Sierras de Almagro, Cabrera and Alhamilla (SE Spain)1961Booy, T. de; Egeler, C.G.40(6)In the Sierras de Almagro, Cabrera and Alhamilla a considerable number of isolated outcrops occur of rocks belonging to the Betic of Málaga. The various elements distinguished tectonically overlie low-grade metamorphic rocks of the Alpujarrides. In the western part of the Sierra de Almagro (southeast of Huércal-Overa) distinction was made between: (1) a Graywacke Formation (Devono-Carboniferous); (2) sandstones and conglomerates (presumably Permo-Triassic); and (3) limestones (Mesozoic (post-Triassic) and early Tertiary).
On the contribution of the Amazon river to accretion of the coast of the Guianas1961Reyne, A.40(6)Arguments are adduced to support Lyell's view, that the recent marine alluvium of the Guianas is mainly derived from the Amazon River. Samples of surfacewater were taken in the Atlantìc Ocean off the coast of Surinam on voyages from Paramaribo to Amsterdam in 1922 and 1924,These samples showed a strip of low salinity at a distance of 85-170 km from the coast, which is almost certainly due to Amazon-water. The sediment of a sample, taken 37 km offshore, was examined by means of an X-ray diffraction diagram; its composition was similar to that of the clay-soils on the coast of Surinam. Some data are reported about the yearly accretion or erosion of the coast of the Guianas, especially of the district Coronie in Surinam (see fig. 1).
in memoriam prof. dr. Jozef Zwierzycki1961Westerveld, J.40(6)
Complementary wrench faults and related structures in the crystalline rockso of the Belledonne Massif (French Alps)1961Kalsbeek, F.; Koning, H.; Tex, E. den40(7)Recent work in the central portion of the Belledonne Massif, French Alps, has established the presence of two sets of wrench faults - one dextral, the other sinistral – with corresponding shear joints, strike-slip cleavages and microfabric S-planes, the latter virtually restricted to the main Sept-Laux granite. It is pointed out that megascopic ,,fish" structures, phyllonites and tension joints, observed in the same general area, are compatible with the movements on these wrench fault systems and fit in with a flattening deformation due to WNW-ESE compression having developed a subvertical B-axis. The age relations of the flattening phenomena with regard to folding, metamorphism and plutonic activity in the ,,Hercynian" basement of Belledonne are discussed and it is concluded that folding and progressive metamorphism are older than the flattening deformation, and that emplacement of the main Sept-Iaux granite is pene-contemporaneous with it. A brief comparison is made with similar features in other parts of the Alps and the possible occurence of more than one phase of flattening is explored.
Notes on continuous parallel slope retreat1961Ruxton, B.P.; Landewijk, J.E.J.M. van40(7)Continuous parallel slope retreat is defined as a continuous translation of all the slope facets above a plain resulting in a constant slope pattern. In the eastcentral Sudan the clay plain may be taken as a plane and the granite hills rising from this are best explained on the theory of continuous parallel slope retreat. Detailed measurements on one small hill, Jebel Qasim, give support for this theory. Continuous parallel slope retreat cannot occur unless the footslope retreats as rapidly as the slope facets above it. In the translation theory we have an inspace-consant velocity of retreat along the translation vector, the rate. Most theories of slope retreat- assume that the footslope retreats at a slower rate than the slope facets above because it is protected by a migtatory layer of rock-waste. In general, footslopes retreat in three ways, by lateral planation, by gradual incorporation of the sedentary weathered rock into the migratory layer, and by subsurface erosion. At Jebel Qasim subsurface erosion, including-mechanical eluviation, is the main agent responsible for continuous parallel slope retreat.
Geologische bibliografie van Nederland196140(7)
Stratigrafische ontwikkeling en correlatie van de koollagen van de Baarlo Groep, Onder-Westfalien A, in Zuid-Limburg met een vergelijking tot die in omliggende gebieden.1961Kimpe, W.F.M.40(8)
Stratigrafische ontwikkeling en correlatie van de koollagen van de Baarlo Groep, Onder-Westfalien A, in Zuid-Limburg met een vergelijking tot die in omliggende gebieden.1961Kimpe, W.F.M.40(8)Large enclosure B1
Stratigrafische ontwikkeling en correlatie van de koollagen van de Baarlo Groep, Onder-Westfalien A, in Zuid-Limburg met een vergelijking tot die in omliggende gebieden.1961Kimpe, W.F.M.40(8)Large enclosure B2
Stratigrafische ontwikkeling en correlatie van de koollagen van de Baarlo Groep, Onder-Westfalien A, in Zuid-Limburg met een vergelijking tot die in omliggende gebieden.1961Kimpe, W.F.M.40(8)Large enclosure B3
Stratigrafische ontwikkeling en correlatie van de koollagen van de Baarlo Groep, Onder-Westfalien A, in Zuid-Limburg met een vergelijking tot die in omliggende gebieden.1961Kimpe, W.F.M.40(8)Large enclosure B4
Geologisch en mijnbouwkundig nieuws196140(8)
Applied science in the mining industry in Great Britain1961Metcalf, B.L.40(9)
Preliminary note on the geology of the Cordillera Vilcabamba (SE Peru), with ephasis on the essentially Pre-Andean origin of the structure1961Egeler, C.G.; Booy, T. de40(9)The stratigraphic column and the tectonic evolution of the Cordillera Vilcabamba in south-eastern Peru are discussed. New data are given on the pre-Carboniferous stratigraphy. Attention is drawn to the pre-Carboniferous age of the widespread volcanic rocks of acid to intermediate character, hitherto assumed to be Permian. The Vilcabamba batholith is proved to be of Paleozoic age (post-Middle Devonian and pre-Middle Permian); it is assumed that the batholitic invasion is related to the major orogeny which marked the close of the Lower Paleozoic. The Mitu volcanic rocks (Permian) prove to be exclusively of intermediate to basic character. Six important orogenic phases are inferred and an estimation is made of their role in the development of the present structure pattern of the Cordillera. This leads to the conclusion that the structural evolution was largely completed prior to the deposition of the Cretaceous sequence. It is clear that the influence of the Andean movements in south-eastern Peru has been unduly stressed in the past.
Geologie and mining in the Netherlands1961Schieferdecker, A.A.G.40(10)
Directional effects of winds, waves and currents along the Dutch North Sea Coast1961Straaten, L.M.J.U. van40(10)As yet very little is known about the movements of sediment along the Dutch North Sea coast. In this paper new data are presented regarding the directions in which sediment transport seems to take place. Some of the main conclusions are as follows. The directions of Dutch coastal dunes appear to vary with a) the primary orientation of the foredunes and b) the relative effect of winds of moderate strength blowing from angles that differ from those of the stronger but less frequent winds. The magnitude of this effect depends on the width of the wind-formed depressions in the dune areas. Wave observations show that sand drift must be strong along the northern barrier islands (from west to east), but that its importance must be small along the more south-north directed part of the coast between Katwijk and Texel. This conclusion seems to agree with direct sedimentological evidence. Comparison of meteorological data with beach measurements between Scheveningen and Bergen reveals that the relatively frequent westerly and southwesterly winds in the second half of the 19th century resulted in an important (temporary) landward shift of the low tide line.
In memoriam, Dr. Ir. P. Tesch m.i.1961Thiadens, A.A.40(10)
Het booreiland Triton196140(10)
Geologisch en mijnbouwkundig nieuws196140(10)
Coal mining section section steinkohlenbergbau Heerlen1961Schieferdecker, A.A.G.40(11)
Directional effects of winds, waves and currents along the Dutch North Sea Coast1961Straaten, L.M.J.U. van40(11)
Preliminary note on the geology of the Cordillera Vilcabamba (SE Peru), with ephasis on the essentially Pre-Andean origin of the structure1961Egeler, C.G.; Booy, T. de40(11)
Jubilee convention - Geology and mining in the Netherlands1961Schieferdecker, A.A.G.40(12)
Volcanology and geology of ignimbrites in Indonesia, North Italy and the U.S.A.1961Bemmelen, R.W. van40(12)(1) An analysis of the orogenic and plutono-volcanic evolution of the Sumatra - Java arc of Indonesia, shows that three impulses of orogenic uplift occurred after its mesozoic geosynclinal subsidence. All three were accompanied by the rise and occasional ignimbritic eruptions of acid magma. Volcanic activity, producing igneous rocks of intermediary composition, developed during the intervening periods (Table I and fig. 1); the latter is the normal type of orogenic volcanism. The ignimbritic type of eruptions differs from the normal orogenic volcanism (Table II). The former produce extensive and voluminous sheets of acid "floodtuffs", which bury the landscape and which are partly welded and recrystallized during their cooling' These ignimbrite deposits are the synorogenic acid counterpart of the post-orogenic, basic plateau basalts, or "flood' basalts", as they were termed by Tyrrell. This ignimbrite type of eruptions may not be compared with "nuée ardente" eruptions. They represent different groups in the classification of volcanic eruptions according to viscosity and gas content of the magma (Table III). However, transitions will occur between ladu's and ignimbrites, between pumiceous air all tuffs produced by Plinian outbursts and ignimbrites, as well as between lava flows and ignimbrites (tufolavas, foam or froth lavas). (2) The quartz-latitic ignimbrites of the Bolzano province in North Italy are related with a cauldron, about 65 km in diameter. From this basin ignimbrite flows of over 100 km length radiate in various directions. These ignimbrites erupted during an acme of volcanism of relative short duration, after an initial phase of volcanism, which had an intermediary composition. The total volume of the Bolzano ignimbrites amounts to several thousands of cubic kilometres. This volcanism was the final act of the hercynic era of orogenesis. (3) The cenozoic ignimbrites of the Cordilleran system have their greatest development in the Great Basin District. Their total volume is estimated at 140.000-200.000 These ignimbrite deposits are probably related with crustal stretching in the crestal part of the Cordilleran tumor as is schematically indicated in a section (fig.2).
On the geology and petrology of the Cape Smith - Wakeham Bay belt, Ungava, Quebec1961Stam, J.C.40(12)The geology and petrology of an area in the western part of the Cape Smith-Wakeham Bay Belt, Quebec is described. A comparison of the various formations and their metamorphic characteristics is made and a cross-section is given, indicating the tectonic structure of the Belt.
Geologisch en mijnbouwkundig nieuws196140(12)
Jubilee convention - Geology and mining in the Netherlands1962Schieferdecker, A.A.G.41(1)
Beachrock at Limani Chersonisos, Crete1962Boekschoten, G.J.41(1)Recent beachrock from Crete is described. The origin of the cementation here is thought to be caused by upwelling calciferous fresh ground water. Aquafacts have been modelled from the pebbles fixed firmly in the rock.
Autoradiographic ore analyses1962Hermans, J.M.A.41(1)Quantitative analyses of uranium- and thorium ores by nuclear emulsion methods is a simple statistical procedure. A. thin nuclear emulsion coating exposed to a mixture of uranium and thorium ore with plaster of Paris, provides an alpha track pattern that is measured. Poisson's distribution is applied to this track pattern.
The emplacement of the Late Hercynian granites in Portugal: a reply1962Schermerhorn, L.J.G.41(1)A recent explanation of the emplacement of the late Hercynian granites of North and Central Portugal in terms of ring intrusions, cauldron subsidence and major stoping caused by tensional fracturing of the crust is discussed. It is argued that the tin-tungsten granite province of Portugal is not comparable to ring-complex provinces elsewhere that wrench-faulting took place, that granite emplacement here can be explained by uplift of the roof with subordinate forceful intrusion and piecemeal stoping, not wholesale crustal collapse, and that the vertical foliation in the porphyritic granites was caused by oriented growth in situ, not by magmatic flow.
Jubilee convention - Geology and mining in the Netherlands196241(2)
Het voorkomen van mijngas en de strijd tegen te hoge concentraties bij de staatsmijnen in Limburg1962Arets, L.A.G.L.; Maas, W.; Muysken, P.J.; Stuffken, J.; Wijffels, F.C.M.41(2)The first part describes the laboratory experiments carried out to determine the amounts of gas that can be adsorbed to the various Dutch coals (as characterized by their volatile matter contents) as a function of pressure and temperature. It further deals with experiments performed to measure the amounts of gas actually adsorbed to coal extracted underground. Whenever in these experiments coal was used that had been subjected to great mechanical pressure variations, whether during extraction or in the stages preparatory to extraction, very low values were found. However, with coal obtained from deep drillings and consequently virtually uninfluenced, the amount of adsorped gas could immediately be measured with fairly great accuracy. The second part gives data on firedamp release during extraction, collected over years, and on the influence on seams under and over the coal seam worked. These data are used for determining the maximum amount of firedamp to be expected in the coal seams of the Dutch mines. By the use of all this information (including the curve relating to the influence on neighbouring seams) it was possible to develop a method of predicting gas release during coalgetting. This part closes with a discussion of some instances in which firedamp had leaked away through breakages in the surrounding rock before extraction starred. The third part describes the efforts made to reduce the firedamp hazard by means of gas drainage. A discussion is given of the various methods employed, and of their merits and limitations. It goes on to deal with the difficulties encountered at the start and at the termination of extraction in a panel. Finally there follows a survey of results obtained with firedamp drainage from various types of face and under various conditions of ventilation. The fourth part is concerned with the variation of the firedamp concentration in the ventilation air during extraction by various methods, both with and without application of firedamp drainage. Then follows a section devoted to the difficulties arising at the place where the firedamp enters the air stream, if the air speed is too low, and a discussion of the solution indicated by S.M.R.E. A table shows how often unduly low air speeds are involved in firedamp explosions. Finally this part deals with the grounds on which requests to be allowed to raise the maximum firedamp concentration in the main ventilation current to 2% were made and granted, and describes some of the experience gained under this condition. The fifth part discusses firedamp release at development and preparation points, particularly at those points where shotfiring is carried out. The sixth and final pair gives, a discussion of some uncommon cases of firedamp release, and deals with possible causes and with the safety measures used.
Le captage et la valorisation du Grisou en Belgique1962Vandeloise, R.; Rosen-Meyer, P. de41(2)
Enige technische aspecten van recente ontwikkelingen in de gasindustrie1962Theron-Mulder, J.C.41(2)Beside the gases based on coal, which have been distributed for many years, a number of gases originating from the oil industry have come forward of late. Their combustion properties often show a strong deviation from those of the classical town gases. Several requirements are mentioned to be met by the combustion when the gas type is changed in a distribution grid. An explanation is given of the way in which a flame is stabilized on the burner mouth. A final exposition shows how burners can be adapted to other gas types by changing the orifice, provided the pressure and the Wobbe number of the gases are related
On joint-patterns in domes1962Schuiling, D.D.41(2)
Enige gedachten over het onderwijs op de mijnschool te Heerlen1962Haverschmidt, R.41(3)
Structural development of the Arabian shield in Palestine1962Ulbo de Sitter, L.41(3)The Palestine region occupies the western, and part of the northern slope of the Arabian shield. Basement faults play a dominant role in its structural features often masked at the surface by warping of the Cretaceous rocks over the deeper seated fault throws. Typical are the monocline structures. The Jordan rift is perhaps originally a large wrench fault, the later subsidence of the Dead Sea is due to a tensional stress field causing normal faulting on the wester border. Superposed successive stress fields of pre-Cretaceous, Pre-Eocene- and Pre-Neogene age can explain the particular features of the fold and fault pattern.
A mixed Rhine-Meuse deposit of the Holsteinian age from the south-eastern part of the Netherlands1962Ridder, N.A. de; Zagwijn, W.H.41(3)This paper deals with a transitional mineralogical zone found intercalated between the zones of Sterksel and Veghel, which were deposited by the Rhine and the Meuse respectively in the S.E. Netherlands. This transitional zone, for which the name of "Zone of Rosmalen" is proposed, could be traced by means of heavy-mineral assemblages. Pollen-analytical investigations of a clay deposit, found near Rosmalen, prove this zone of mixed Rhine and Meuse sediments to be of Holsteinian (= Needian) age.
A mixed Rhine-Meuse deposit of the Holsteinian age from the south-eastern part of the Netherlands1962Ridder, N.A. de; Zagwijn, W.H.41(3)Enclosure
Un aspect de la végétation en espagne méridionale durant la derniére glaciation et l'holocène1962Menéndez Amor, J.; Florschütz, F.41(3)This paper deals with the results of a palynological analysis of a 20m layer of peat, calcareous mud and clay near Granada in southern Spain. Obviously, it has been formed during the whole last glaciation and a part of the Holocene
On the so-called "konglomeratische mergel" in the Sierra de Los Filabres (SE Spain)196241(3)
50 jaar Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 1912-19621962Sitter, L.U. de41(4)
A dive into the history of the Royal Geological and mining society of the Netherlands1962Wijs, H.J. de41(4)
Presentation of the Van Waterschoot van der Gracht medal to Doctor E. Anderheggen, Doctor E. Kündig, Professor F.B. Hinsley, Professor P. Pruvost.196241(4)
Past, present and future subsidence1962Faber, F.J.41(4)
Geological research at the universities of the Netherlands 1877-19621962Pannekoek, A.J.41(4)
Development of geo-hydrological knowledge and research in the Netherlands1962Krul, W.F.J.M.41(4)
#REF!196241(4)Veiligheid in kolenmijnen
Ansprache von Herrn A. Hellemans, generaldirektor der staatsmijnen196241(5)
Die neueste entwicklung der Technik des Streckenvortriebes in den Limburgischen Steinkohlenbergwerken1962Debets, G.B.41(5)The development, the preparatory work and the coalgetting required per 1000 n.t. production, since 1958 the driving of about 15 m roadway in the rock and in the coal. The roadways are generally trapezoidal with a working face of ca 9 m2 in the rock and of 5-8 m2 in the coal seams. The driving of roadways in the seams before the coalgetting has started has increased owing to a more extensive application of the retreating or semi-retreating system. The driving of roadways in advance of the face has consequently diminished. In order to obtain a decrease of the cost of driving the roadways, an increase of both the daily advance of the roadhead and its advance per manshift has been aimed at. In driving horizontal stone drifts an average daily advance of circ. 300 cm and an output per manshift of 28 cm have been attained by the application of higher speed drills, simultaneous loading of the muck by 2 throw shovel loaders or of high capacity shovel loaders. The introduction of safety explosives, class II and III enabled the blasting in one round of the complete lift consisting of coal and stone in the roads. For mechanical loading in the non-horizontal straight gate roads the scraper loader is mostly used. In these roadways, an average daily advance of 431 cm was obtained during the first half of 1961 with an output per manshift (all transportshifts included) of 30,5 cm. The corresponding results in gate roads in advance of the face were 298 and 29,2 cm. Machines suitable for breaking the coal and the stone and simultaneous loading are not yet applied in the Limburg coal district.
Der stand der Fördertechnik in den Nierderlanden1962Clercq, H. le41(5)
Forschung und entwicklung im Bergbau1962Braaf, W. de41(5)The fifty years that have elapsed since the establishment of the "Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap" have witnessed a considerable advance in mining techniques. The more complicated the techniques became the greater was the necessity carefully to make a quantitative analysis of the facts and to base the work of development on the results of this analysis. In the Netherlands, where somewhere about 1930 research work has begun to be carried out in a more organised and centralised form at Staatsmijnen, the interest went out especially to the improvement of coal preparation methods at first. Later the underground workings, too, were brought within the scope of the research work, which led amongst other things to the development of the Titan Servo-prop. Afterwards, about 1950, with a view to the flew shafts that had to be sunk, a large part of the available capacity was used to introduce improvements in the way of shaft linings and shaft sinking procedures. About 1957 the emphasis was placed on the increase of the productivity. Some characteristic aspects of the mining research work at Staatsmijnen are: 1) The necessity to make a choice from the great number of problems, which is due to the comparatively small size of the industry. The cost of research amount to half a guilder per ton as it is. 2) The close proximity of the mines to each other. I Coal face support After a fatal accident at Maurits Colliery in 1958 a jack ring (Fig. 1) was developed, permitting the Titan Servo-props to be put in piece with an initial load of 10 tons. Immediately after the introduction of hydraulic props in 1957 leakage of the relief pressure valve gave rise to difficulties. The design of this valve was therefore so changed, that it is now proof against polluted water (Fig.2). II. Mechanical getting of coal The idea that the coal getting machine should be as narrow as possible led to the construction of the multiplough. For a long time a considerable percentage of the coal mechanically won by Staatsmijnen has been produced by this plough, which in the last few years is, however, being superseded by the rapid plough. A more systematic investigation into the mechanics of the coal getting equipment was begun by studying the planing of coal and slate on a planing bench specially designed for this purpose. Afterwards measurements at the ploughing equipment in the underground workings were conducted. Several instruments were developed to this purpose (Figs. 3 and 4). A clearer insight into the phenomena was only obtained after the above measurements had been completed by model tests on a small scale (1 : 4) (Fig. 5) in the laboratory and by tests carried out with a full-scale test set-up on the surface (Fig. 6). Owing to these investigations several particulars regarding the action of the rapid plough could be explained (Figs. 7, 8, 9), and the design of the plough be improved (Fig. 10). The power consumption of thea conveyor and the plough was analysed (Fig. 11), so that the forces determinative of the power needed to drive the conveyor and the plough can be calculated. The properties of the system consisting in electric mains-motor-coupling-tool were also subjected to a quantitative analysis. III. Support of roadways and large spaces. In the last few years rather much time has been spent on an investigation, subsidised by the Coal and Steel Community, that has for its aim the improvement of the support of roadways, more in particular the reduction of maintenance costs in that respect. In a roadway which was divided into a number of test sections, all being supported in different ways, the movements of and the loads on the supports were measured (Figs. 12 to 17). For several years past investigations have been conducted into the influence of rock pressure on the concrete lining of shaft stations. Attempts are being made to draw conclusions from these measurements regarding the mechanical constants of the rock in situ (Fig. 21). lV. Communication; automation: signalling; transmission of measuring data. It is already some years ago that a duplex communication system was developed to maintain the communication between the control room and the engine drivers of a level (Fig. 22). A subsequent development is the electro-magnetic car detector (Fig 23). After these developments which are of a more incidental nature some larger projects are now in hand: 1) The automation of the disconnecting of mine cats, the tipping of the full cars in a tippler, the loading of a skip, and the connecting of the empty cats (Fig. 24, 25). 2) The automation of locomotive haulage at the shaft stations (Fig. 26). 3) The development of a control centre to be located at the district, showing and/or recording the principal data about the coal getting installation, so as to ensure the most efficient operation of this installation. V. Firedamp. The investigations made into the problems associated with firedamp were originally concerned with the forecasting of the quantities of methane that could be expected when new parts of a coalfield were to be worked (Fig. 27). With the assistance of the figures collected over a period of more than 30 years a method was developed permitting of calculating in advance, With sufficient accuracy for practical purposes, the quantities of CH4 that could be expected, provided the rank and the stratigraphic profile of the coal field in question be known. As a consequence of the ever more concentrated getting of coal the methane released threatened to impose a limit on the production of some district. This gave rise to the development of methane drainage installations at two mines. However, in recent years the production per district has risen to such an extent that, notwithstanding the drainage of methane, the regulation that the CH4 concentration in the air must not exceed 1½ % set a limit to the output of some districts. An extensive study of the nature of the gas emission in a district and the work already done in this field by the S.M.R.E. of Sheffield made it clear that no objections were attached to raising the allowed percentage to 2%, provided the air velocity is not lower than 2 m/sec. The emission of methane in places where preparatory works are going on is being studied, too. VI. Heat. For several years past investigations have been carried out into the question of how the climate in the underground workings comes about under influence of the various sources of heat and humidity. By recording temperature and humidity over a longer period of time (Fig. 33) heat balances can be drawn up for several airways, When these balances tally this means that the valuation of the sources of heat and humidity has been correct. A further study was made of the heat emitted by the rock round a roadway (Fig. 34). The investigation has now so fat progressed that the climate at new faces can be predicted with sufficient accuracy for practical purposes and the effect which certain measures have on the climate can be calculated in advance. Vll Concluding remarks. In this lecture an attempt has been made to give an idea of the contributions the largest Dutch mining company has made to the research and the development in mining. The above results could only be obtained thanks to services, this co-operation being strongly promoted by the fact that the research establishment is situated in the midst of the mines.
Der derzeitige stand in der mechanisierung der kohlengewinnung im Limburgischen steinkohlenrevier und ausblick auf die zukunft1962Snell, A.W.41(5)The present stage of the mechanization of coal getting in the Limburg mining district, and expected future developments. The rise inwages and social overheads, added to the shortage of labour, has necessitated the introduction of far-reaching mechanization programmes in the mining industry. The object of mechanization in coal getting can be described as: extracting the largest possible amount of coal per 24 hours and per working point by the use of mechanical means in an economically justified way with the employment of the smallest possible number of men. The various coal-getting installations used are discussed in succession. They include: the scraper box installation, the single standard plough, the multiplough, the rapid plough, and the Peissenberg ramming installation. A sketch describing the developments in face supporting makes it clear that excellent results are expected to be obtained With the hydraulic self-advancing support, which is now being introduced at an increased rate. The second part (Results obtained, and expected future developments) deals with the various aspects of the attainment of the object of mechanized coal getting stated above, viz. the degree of mechanization, the saving in manshifts, the concentration, and the improvement in the size variation. For each aspect a discussion is given of: - the results achieved so far; - the ways in which these results were obtained; - mining-technical and constructional problems, and the ways in which they are expected to be solved. Finally, some remarks are given on the signalling of operating troubles by remote control systems, the capacity of the conveyors for product removal, and the training of personnel.
60 jaren staatsmijnen in Limburg196241(5)
Anwendung von sintronic hartmetall im bergbau1962Berndt, F.41(5)
The inaugural session of the jubilee convention knight's hall (ridderzaal), the Hague, april 26th, 1962196241(6)
Igneous and structural features of Thailand1962Klompé, T.H.F.41(6)This paper presents a survey of the igneous and structural features of Thailand and their possible ages of emplacement and development. Three groups of igneous rocks are distinguished. Oldest are mafic to ultra-mafic rocks in North Thailand, intrusive in the Silurian-Lower-Carboniferous Kanchanaburi Series, they might represent the results of an initial geosynclinal magmatic activity. The Mesozoic granites are represented by an older, Upper Triassic granite in the eastern, and a younger tin-bearing granite in the western part of the country. The age of this last granite is considered to be post-Triassic. Recent age determinations on granites from Billiton .and Singkep have revealed that they were emplaced some 145-155 m.y.ago. The youngest representatives are various kinds of effusives and some dioritic intrusions of Upper Tertiary and Pleistocene age, they are related to important faulting features. Structurally Thailand can be divided in a western and northern mountainbelt, the Korat plateau in the east, and the depression of the Gulf of Thailand in between. The first unit consists of a conformable Paleozoic- sequence, locally conformably capped by Triassic deposits. The disconformities in the sequence are ascribed to epirogenic movements at times when in areas further east, important orogenic movements took place. The regularity of this sequence, the age of the granites and the unconformable contact between the folded layers and the overlying late Jurassic to early Cretaceous deposits in adjacent areas (Malaya, Borneo, Sumatra), favour an Upper Jurassic (young-cimmerian) phase of mountainbuilding. In the Korat Plateau the folded paleozoic sequence is unconformably overlain by the almost horizontal Rhaetic-Liassic and younger members of the Korat Series. This unconformity and the age of the granites favour an Upper Triassic (old-cimmerian) phase of diastrophism for the basement in the eastern part of the country. The depression of the Gulf of Thailand is the result of faulting. The northern part of this depression is gradually filled with alluvial deposits and the coastline is pushed southward approximately 4 to 5 meters per year. The structural features of Thailand and adjacent areas form an excellent example of zonal growth in this part of Asia.
Preliminary note on the origin of the so-called "Konglomeratische mergel" and associated "Rauhwackes", in the region of Menas de Serón, Sierra de los Filabres (SE Spain)1962Leine, L.; Egeler, C.G.41(7)The origin is discussed of the problematic rock types within the Triassic of the Sierra de los Filabres, that are usually referred to in the literature as "konglomeratische Mergel" (conglomeratic marls). An explanation is suggested for the considerable variation in character and the often heterogeneous composition of these rocks, which in the Menas region are represented as concordant discontinuous bands and masses in epimetamorphic as well mesometamorphic structural units. Arguments are provided for a tectonic origin, the rocks being interpreted as breccias resulting from differential movements within the rock sequence during intensive thrusting – a process in which the lithology of the initial sequence and especially the presence of highly incompetent beds of anhydrite or gypsum, perhaps in association with other salts has played an essential role. It is shown that the brecciation proceeded, at least for an important part, during a relatively advanced stage of the tectonic evolution, i.e. after the kinematic stage of the regional metamorphism, which is tentatively linked with overthrust movements leading towards the development of the nappe structures. These structures are considerably disturbed by late overthrusting and the provisional results seem to suggest that the provisional largely during these late movements. Special attention is drawn to a superimposed static metamorphism, which has a contributed in considerable measure to the ultimate character of the breccias by giving rise to the growth of a number of new minerals. The close relation between the heterogeneous type of breccias and the associated “Rauhwackes” is pointed out and it is suggested that the latter are tectonic breccias very poor in or devoid of fragments other than of dolomite, selective weathering having accentuated the breccia-structure.
The occurrence of gneissic amphibolites in southwest Puerto Rico1962Renz, O.; Verspyck, G.W.41(7)Quartz-bearing amphibolites and metamorphosed basic dyke rocks are described and are compared with amphibolites known from the literature concerning the area. The presence of sodic plagioclase and blue-green hornblende seems to indicate that medium-grade regional metamorphism occurred. The age of the rocks is briefly discussed and their relation with the surrounding serpentinites reviewed
Sur la genèse du dôme gneissique de l'agout (dépts. Tarn et Hérault)1962Schuiling, R.D.; Widt, M.J. de41(7)Tectonical and microtectonical data suggest that the emplacement of the gneissic dome de l’Agout took place under increase of volume, simultaneously with subsidence of the bordering schists. There can be no doubt that the gneisses possess a sedimentary frame, although their mineralogy shows a clear difference between schists and gneisses, which is also evident from a series of partial chemical analyses (Na, K, Cr). One is bound to suppose that here has been an important addition of mobile elements (in the order of 60-70%). These mobile elements, the “mobilisate” were expelled from the deeper levels of the micaschists (hence subsidence of these) along the planes of schistosity to higher structural levels, where they caused swelling of the schists in the places of deposition and their transformation into gneisses. The most mobile elements (Na, Si, B) were deposited in particular just below the schist-gneiss boundary (the front of migmatization). Chrome, a refractory element, is diluted beyond detectability in this particular outer zone; otherwise, compared to the schists, it is diluted 2-3 times in the normal gneissic succession. The rapid succession of metamorphic zones (biotite, garnet, andalusite, staurolite) surrounding the dome is indicative of a strong thermal gradient, i.e. a kind of contact-metamorphism. It is impossible to say whether this thermal metamorphism is mainly due to the tectonical emplacement of hot deep-level rocks in colder epizonal schists, with concomitant stretching and thinning of the limbs of the dome, or whether it was the hot “mobilisate” that was the principal cause of this metamorphism.
Geologisch en mijnbouwkundig nieuws196241(7)Terugtrekken van de gletschers in het Carstenszgebergte (Nederlands Nieuw-Guinea)
Palynological and sedimentary petrological data of a section in ice pushed deposits (Southern Veluwe, Netherlands)1962Polak, B.; Maarleveld, G.C.; Nota, D.J.G.41(8)A section of ice-pushed deposits in the southern Veluwe area was investigated. It was possible to ascertain its stratigraphical position by means of a combined palynological and sedimentary petrological study. The palynological data agree rather well with those of the warm-temperate section of the Cromer interglacial period, but show some similarity with Saalian (Eucomnia, Carya type). The results of the sedimentary petrological study have been summarised in Table 3.
Cinérites of the Mont Dore, Central France1962Rutten, M.G.41(8)Cinérite is a local name for acid ash and tephra deposits of the mid- to late Tertiary volcanic region of the southeastern Massif Central, France. The two varieties distinguished, viz. fine grained cinérite and cinérite à blocs, are generically different. The former represent ash falls on a low, waterlogged peneplain, outside the actual volcanoes. The other is a laharic breccia formed on the cones of stratovolcanoes.
Cleavage-Boudinage in Precambrian rocks at Jasper, Alberta1962Charlesworth, H.A.K.; Evans, C.R.41(8)Slaty cleavage in the argillaceous strata of the Precambrian Old Fort Point formation is arranged in a fan-like manner about the axial planes of folds. The origin of the cleavage-fan may result from the tendency of cleavage to lag behind folding or from that of the maximum principal stress-axis trajectories to be refracted towards bedding. Deviation from the regular cleavage-fan may be caused by variation in competency of the argillaceous layers and by the effect of interbedded competent strata. Cleavage-boudinage, restricted to thin siltstones surrounded by cleaved argillaceous rocks, is present in the steep limbs of asymmetrical folds. An analysis of the extension involved in the development of the boudinage suggests that shear parallel to cleavage occurred during at least part of the fold-history. On the other hand, rotation of the boudins into the plane of slaty cleavage indicates that considerable shortening perpendicular to cleavage may also have taken place.
Geologische bibliografie van Nederland196241(8)
Gegenwärtiger stand und entwicklungstendenzen der mechanisierung der abbaubetriebe im Ruhrgebiet bei verschiedenen lagerungsverhältnissen1962Brandi, K.41(9)
Geology of West Amberbaken (New Guinea)1962Valk, W.41(9)In West Amberbaken andesitic rocks prevail. They are propylitized and mineralized, but no ore deposits of economic value have been formed. After andesitic vulcanism had come to an end, tilting and faulting in late Tertiary time created a bold relief. Then followed the deposition of a sedimentary series starting with coarse conglomerates. Folding of the sedimentary basin took place during the Mio-pliocene or Pliocene.
A survey of the Efar-Sidoas mountain ridge in Northern Netherlands New Guinea1962Dun, F.W.P. van41(9)Data obtained during earlier surveys (Zwierzycki, 1921) rendered it necessary to renew the geological explorarion of the hinterland of Sarmi, where the central part of the Efar-Sidoas anticline was reported to consist mainly of basement (igneous rocks and crystalline schists). It appeared, however, that the Efar-Sidoas mountain ridge is made up almost entirely of Neogene folded sediments; the crystalline core occurring only in a few isolated areas. Consequently the attached sketchmap differs considerably from Zwier zycki's map. No mineralizations were detected neither in the basement nor in the Neogene sediments.
Indrukken van het derde I.M.A.-congres, Washington, 17-20 April 19621962Uytenbogaardt, W.41(9)Indrukken van het derde I.M.A.-congres, Washington, 17-20 April 1962
Geologisch en mijnbouwkundig nieuws196241(9)
in memoriam Prof. Dr. Ir. J. Westerveld1962Roever, W.P. de41(10)
Some applications of Faber's method for grain size analysis by counting1962Mabesoone, J.M.41(10)The method for the determination of size frequency distribution of sands by counting individual quartz grains, as developed by Faber, is compared with other methods in which either sieving or counting techniques are used. It appears that the results obtained by Faber's method have no ¡elation to those obtained by the other methods, because the approach is fundamentally different. Faber's method is applied to determine roundness, spread, and median grain diameter of various fluvial deposits. Then a number of samples from the Netherlands is compared with the former. It appears that these Dutch sediments are much better rounded. It is presumed that they were derived from rocks which contained already rounded grains. Finally the method is applied to deposits of the marshy coastal plain of the Guadalete river in S.Spain. It is concluded that the former estuary of the river has been filled up by this river itself, and not by the sea.
Preliminary note on the presence of distinct tectonic units in the Betic of Málaga of the Vélez Rubio region (SE Spain)1962Roep, T.B.; Gillavry, H.J.M.41(10)The Betic of Málaga is considered to be complex and to consist of a number of distinct tectonic units. These are from north to south: the Salud, Castillos, Cerro Colorado, and Casolidad units. The northernmost (uppermost) Salud unit is characterised by the presence of Oligocene transgressively overlying Triassic or Permo-Triassic. The Castillos unit, directly to the south of the former, is characterised by Eocene transgressively overlying Cretaceous or Upper Jurassic; its Mesozoic stratigraphy corresponds with that described from the region of Málaga (Azéma, 1961) and from the Sierra de Espuña (N. & Y. Peyre, 1960); Novakia- limestone intercalations in the Upper Paleozoic, and Carboniferous conglomerates of the Marbella-conglomerate type, seem to be restricted to this unit. The Cerro Colorado unit contains Paleozoic, Permo-Triassic sandy formations and Triassic dolomite. The Casolidad unit, situated furthest south, contains only Paleozoic and Permo-Triassic, the latter being characterised by the occurrence of thick, coarse quartz conglomerate intercalations; it shows some Alpine metamorphism. The separation of the two last-named units is still tentative. The stratigraphic and tectonic implications are discussed. It is suggested that the Betic of MáIaga was imbricated by thrust movements after deposition of the Salud Oligocene, prior to the first nappe-movements of the Betic of MáIaga complex as a whole.
Lead isotope studies of the lead-zinc deposits in southern Limburg, The Netherlands1962Priem, H.N.A.; Boelrijk, N.A.I.M.; Boerboom, A.J.H.41(10)Among the galenas of the lead-zinc ores in southern Limburg two groups of lead model ages can be distinguished, one averaging 430.106 years (Upper Ordovician-Lower Gothlandian) and the other averaging 345.106 years (Lower Carboniferous). This points to Caledonian and early Hercynian ages of generation of the lead ore. The ore deposits were emplaced in post-Westphalian time, at least in part during the Upper Cretaceous, so that we are dealing with B-type anomalous lead. This supports the hypothesis of a genesis of the ore by regeneration from older deposits. The calculation methods and some geochemical implications are discussed.
Geologisch en mijnbouwkundig nieuws196241(10)
Stofgrenzen1962Matla, W.P.M.41(11)The first part, an introduction, gives an indication of changing opinions on dust limits which may be expressed in terms of weight, surface or number of dust particles, or in other parameters. The second part mentions foreign limits, adopted, recommended or derived. It is not always possible to give the motivation or the origin of the limits since, in many cases, this has not been published. 'the third part treats the dust limits adopted by the Netherlands Coal Mines on the advice of the Stofinstituut van de Gezamenlijke Steenkolenmijnen in Limburg (Dust Institute of the Association of the Netherlands Coal Mines); other dutch opinions on dust limits are given too. The fourth part gives, on the basis of available data, comparisons between different dust limits, in the first place comparisons between foreign dust limits and those recommended by the Stofinstituut. The fifth part considers the re-employment of pneumoconiosis cases. The sixth part is a list of references. To avoid possible misunderstandings the author makes ample use of literal foreign texts. Commentary is not given, and the report does not close with a conclusion by the author.
Geologie en geofysica (werkwijze en enige resultaten)1962Bemmelen, R.W. van41(12)The stages of cosmic evolution are characterized by leading principles of development. During the stellar evolution nuclear reactions , producing the chemical elements, were the leading principle. During the planetary evolution the energy production is chiefly based on molecular integrations (reactions of the electronic shells of the elements) and nuclear desintegrations (natural radioactivity). The successive stages of the universal of evolution with emergent principles of development are: galactic, stellar, planetary, biotic, and psychic (van Bemmelen, 1948; Teilhard de Chardin, 1958). For the scientific research of these stages the prognosis-diagnosis method can be applied (Fig.2). For instance, the model of a layered earth leads to the expectation that the earth will have a specific spectrum of vibrations, when struck like a bell by a heavy earthquake. The frequencies calculated by Pekeris and others are a prognosis which has been verified by the diagnostic observations at the observations at the occasion of the Chili-earthquake of May 1960. A fair correspondence between prognosis and diagnosis has been found up to the 38th overtone. This means a check of the correctness of our mental picture about the structure and physical of the inner part of the earth. Paleomagnetism is a new method of measuring geophysical properties, which provides the geologist with diagnostic observations for testing geotectonic concepts. It appears that indeed polar wandering and continental drift, as suggested by Wegener half a century ago, did occur on a grand scale during the geological evolution. A synthesis of our concepts concerning the geological evolution can be based on two leading principles: (A) Physico-chemical processes are the source of the endogenic energy of the earth (plutonism sensu largo); (B) these processes are accompanied by changes of density, which cause accumulations of potential energy. The resulting stress fields will give rise to flow-circuits of matter of various dimensions (gravity tectonics sensu largo) (van Bemmelen, 1958). Thus the prognosos-diagnosis method leads us to the insight that the geotectonic evolution does not occur solely according to the fixistic concept or the mobilistic concept; but rather according to a combination of both, fixism and mobilism.
Memorandum betreffende het energiebeleid196241(12)
In memoriam Dr. G. Zijlstra196342(1)
De geologie van het eiland Waigeo1963Wegen, G. van der42(1)Waigeo, Batanta, Salawati and numerous smaller islets of the western tip of the mainland of New Guinea form the Radja Ampat archipelago. Waigeo and its surrounding islands were visited for the first time by Verbeek in 1908, during his geological reconnaissance of the eastern part of the former Dutch East-Indies. Neither Verbeek nor subsequent visiting geologists (Brouwer, Molengraaff, oil geologists a.o.) penetrated deeply into the island's interior. We have, nevertheless, a reasonable clear insight into its geology, which is mainly due to Verstappen's geological interpretations of aerial photographs. Ultrabasic rocks are present in a narrow belt along the north and west coasts of Waigeo and on some of th islets in the inmediate vicinity. They were followed by other basic and intermediate rocks, among which such charateristic effusiva as spilites and keratophyres. These ingneous rocks accompany the initial geosynclinals subsidence and present its simatic magmatism to a high degree of completeness. Together with pelagic limestones, pelites, radiolarites and chert they were strongly folded. Deposition of graywackes, conglomerates, volcanic breccias, quartz-) andesites and tuffs, cut by basalt dikes followed the folding. According to the oil geologists who visited some of the coastal areas of Waigeo the above mentioned rocks, with the exception of the ultrabasic rocks, belong to the so-called Batanta-formation and are of Oligocene to early-Miocene age. There are reasons to assume an uncomformity within the Batanta-formation. This intraformational uncomformity points to synorogentic conditions of sedimentation which, although of limited extent, led to the flysch sedimentation during early Miocene time. In a fully developed eugeosynclinal cycle the initial magmatic phase is followed by a synorogenetic or sialic and a final, simatic or basaltic phase. There are some indications of magmatic actvities during the Lower-Miocene. Limestones and marls of the Waigeo-formation (Upper-Miocene and Pliocene) indicate a very extensive transgression during the Upper Tertiary of Western New-Guinea.
#REF!196342(1)KNGMG Jaarverslag 1961
Coastal sediments and coastal development near Cádiz (Spain)1963Mabesoone, J.M.42(2)The coastal area of the W part of the province of Cádiz (Spain) shows various beaches alternating with some cliffs; near the city of Cádiz the Guadalete river flows into the sea. This coast can be divided into three parts: (1) the part N of Sta. Catalina, (2) the part S of Cádiz, and (3) the inner part of the bay. Recent beach sands point to a supply from the adjacent land, particularly where cliffs are exposed. The south-easterly longshore current had only a minor influence. These features are presented by means of socalled historiograms. The dunes received their material from the adjacent beaches by the action of onshore winds. Bottom dedosits of the bay show a Pliocene sediment, sometimes mixed with younger material. Beach and dune sands can be distinguished by means of the skewness values of their grain size distribution, following indications provided by Mason & Folk. By means of this method a distinction between beach rock and eolianite could also be made with respect to the cemented deposits found alongside the modern shore. From ancient beach and dune sediments at various levels and the height of the cliffs, four stages of Quaternary coasts could be mapped. The oldest coast from the Milazzian time survives at present only in some isles in the investigated area, During later stages the coasts approached the site of the present one, although this latter, which is in retreat, lies somewhat landward from that presumed in the Tyrrhenian II and III periods.
Europa und die Energie196342(2)
10e Leobener Bergmannstag - 12-16 spetember 19621963Martens, A.H.W.42(2)
Indications for large scale grabenformation along the continental margin of the eastern United States1963Engelen, G.B.42(3)Geophysical, geological and topographical data about the continental margins of the northern Atlantic and the Arctic Ocean, collected by Heezen, Holtedahl and others, were studied by applying various working hypotheses to these primary data. In this way the picture of a big graben structure under these continental margins, parallel to the coast, was deduced. This riftzone fully developed during the Miocene in a sedimentary deltaic sequence, that was deposited from the early Cretaceous to the middle Tertiary as a long "ribbon" on the continental margins along the coasts. The adjacent continents seem to have been elevated temporarily at the end of the Tertiary. In the emerged continental slope (the limiting faultplane on the continental side of the graben) canyons could be formed by subaerial erosion. The continents should have sunken back again during the Pliocene with almost the same vertical amount and thus the canyons got drowned. Isostatic readjustment to compensate for the erosion on the continents and sedimentation in the continental margins seems to be one of the causes for the inferred sequence of events. The continental margin along the western side of the North Atlantic Ocean is treated in some detail as an example.
Het vierde internationale kolenwasserijcongres1963Baerts, J.W.R.42(3)
De slikverwerking1963Bitter, J.H.42(3)
Note on geological developments in southeast Asia1963Valk, W.42(3)
Geologisch en mijnbouwkundig nieuws196342(3)
Geologisch begrip1963D'Arnaud Gerkens, J.C.42(4)
Comment varient dans l'Espace les structures geologiques1963Pruvost, P.42(4)
Een vulkanisch sediment in de ondergrond van de Betuwe1963Crommelin, R.D.42(4)
Some time relations of movement and metamorphism in the Scottish Highlands1963Johnson, M.R.W.42(5)The paper attempts to summarise recent work on time relationships of deformation and crystallisation in the Moine and Dalradian rocks of the Caledonian orogenic belt in Scotland. Three or four deformation episodes, each accompanied by some kind of metamorphism, have been detected. Crystallisations of metamorphic minerals can be shown to have accompanied and, more especially, followed a particular episode of deformation and so the observed metamorphic fabrics result from a complex interplay of deformations and crystallisations. Rocks may contain disequilibrium assemblages, with the metastable survival of early crystallised minerals. In the Dalradians, and probably the Moines also, the earliest known movements, which caused great thickening of the sedimentary pile, were accompanied by only low-grade, dynamic, metamorphism. The main episodes of crystallisation occurred before, during and after the second deformation. The three episodes are part of a continuous, perhaps progressive, metamorphic process, which possibly embraced some local oscillations in P/T conditions. The third, final, episode of crystallization - an important and extended static period between the second and third fold movements - often marks the climax of the crystallisation and grain growth resulting in the build-up of schistose or gneissose fabrics. During this episode in the Dalradians there were regional crystallisations of kyanite-sillimanite ("Barrovian type") and andalusite-sillimanite ("Buchan type") sequences. The occurrence of these sequences at different structural levels is thought to have been controlled by orogenic P/T gradients. An account is included on current work on problems of dating the migmatites in the Scottish Highlands. A separation in time between migmatitic and regional metamorphism has been proposed at various times by different workers. Recently it has been suggested that the Dalradian migmatites and associated sillimanite have been superimposed upon the pattern of andalusite/kyanite metamorphism. The available evidence bearing on this problem is discussed. The migmatites appear to show a different, perhaps more prolonged history of crystallisation than do the non-migmatitic rocks. T/P oscillations may have played an important part in the evolution of the migmatite fabric and the climax of crystallisation in the migmatite zones may not have have been attained at the same time as elsewhere. Although the history of crystallisation in relation to deformation in the Moines follows a broadly similar pattern to that in the Dalradians it has yet to be established that the regional metamorphism Moine and Dalradian tracts are coeval. Indeed, recent geochronological work, to which brief reference is made, suggests they may not be coeval.
Some examples of the relations between deformation and metamorphism from the Central Pyrenees1963Zwart, H.J.42(5)Four examples of relations between deformation and metamorphism are discussed. In the Bosost area a folding phase with N-S axes is accompanied by uniform rotation of minerals, indicating that the schistosity is a plane of shear and that the folds are shearfolds. Another phase of deformation consists of two sets of folds perpendicular to each other. Their shearfold character and contemporaneity cannot be proved in steeply dipping slates, but in the schists of the Hospitalet massif rotation of minerals again is demonstrative of this type of folding. A detailed scheme of the metamorphic history of the Bosost area can be established by dating the minerals with four phases of deformation. The order of crystallization shows increase in temperature during a large part of the metamorphic history. The mineral assemblages are formed under low confining pressure. Two types of gneisses occur in the Pyrenees, gneisses with regular schistosity and lineations and migmatitic gneisses with strongly folded schistosiry. The relationships between these gneisses and their metamorphic grade indicate that metamorphism of the first group took place under drier conditions.
Ablauf und Altersverhältnis der Postvaristischen tektonik und metamorphose im Westalpenbogen1963Wunderlich, H.G.42(5)The tectonic and metamorphic processes in the western Alps are characterized, by a regular chronological sequence of activities encompassing thrusting, folding and formation of secondary fabric elements. Alpine metamorphic crystallization and magmatism; all these events occurred in course of the deformation of the geosynclinal prism. Thrusting, folding and penetrative movements set in at the innermost parts of the Alpine chain and become successively younger when proceeding to the northern and western edges of the depositional basin. Folding and penetrative movements, giving birth to schistosity and lineation (in N-S and E-W direction), are always younger than the thrusting, when considering the individual and successively deformed sectors of the mountain chain. The Alpine regional metamorphism has been found to be restricted to certain areas within the internal, most strongly deformed parts of the area, where the metamorphic crystallization goes hand-in-hand with the penetrative movements, ultimately post-dating the same. A certain time-place relationship between the metamorphism and Alpine magmatism (Traversella, Biella, Iorio, Bergell, Adamello) is obviously present, pointing to a genetic relationship between the two. The depositional basins, filled up by orogenic sediments, are shifted slowly towards the outer edge of the Alpine chain and are themselves followed by thrusting and folding movements. All these events, however, were brought to an end with the late thrustings in the external parts of the mountain and folding of the sub-Alpine chain. Thereupon the regional uplift followed.
A commentary on the correlation of the metamorphism and deformation in space and time1963Tex, E. den 42(5)
Some remarks concerning the scarcity of retrograde vs. progressive metamorphism1963Schuiling, R.D.42(5)
Aspects of the genesis of bituminous rock sequences1963Bitterli, P.42(6)From the investigation of some 150 W. European, primary-bituminous rock sequences of Cambrian to younger Tertiary age, it is concluded that bituminous material occurs in a great variety of sediments (shales, carbonates, clays, siltstones, etc.), though predominantly in fine-grained and laminated rocks. Favourable situations for the formation of bituminous sequences seem to be often created at palaeogeographic turning points (orogeneses; epeirogenic or eustatic oscillations) which resulted in either transgressions or regressions and were followed by stagnation and anaerobic conditions. As regards environments of deposition of the sequences studied, a, great many occurrences are of a transitional or an alternating facies; brackish and mainly limnic deposits often show higher concentrations of organic matter and thicker beds than marine deposits. As regards the genesis of bituminous rock sequences, the interplay of various climatic, physico-chemical and other factors, governing or influencing type and amount of organic matter, inorganic components, anaerobic conditions, etc., is of great importance. Depending on whether these conditions continue more or less uniformly for a certain time, or alternate periodically, there will result: a) continuous (homogeneous) or b) cyclic (rhythmic) sequences; unsettled conditions and irregular repetitions will end in c) complex sequences. In an attempt to subdivide the many bituminous sequences studied. according to the original depositional environment, various types of basins and other aquatic realms are recognized, which can be groupel in: 1) open marine, 2) transitional, and 3) continental.
A peat-layer of Early Würm glacial age1963Polak, B.; Hamming, C.42(6)A deposit, representing a zone of the Brørup Interstadial of the Würm glaciation is described. This deposit was found in the north-eastern part of the province of Overijssel. So far sediments of the Brørup Interstadial were only known to be present at Amersfoort and this find thus represents a second occurrence in the Netherlands.
Erfahrungen mit 865 V-Niederspannungsanlagen im Holländischen Grubenbetrieb1963Kempen, W.; Reyen, C. van42(6)
Ontwikkeling van de diepte-injectie op de mijn Julia1963Bianchi, M.; Hooijdonk, J. van 42(7)
Henry Clifton Sorby and the sedimentary structures of sands and sandstones in relation to flow conditions1963Allen, J.R.L.42(7)The scheme of sandstone facies in relation to increasing intensity of fluid flow developed by Sorby is modified in the light of recent experimental studies, as follows: small scale cross-stratification + large scale cross-stratification (cosets) + flat-bedding with primary current lineation. A. cyclothem probably of fluviatile origin from the Lower Old Red Sandstone (Lower Devonian) of the Anglo-Welsh Basin is analysed to demonstrate the practical value of the scheme in the interpretation of facies.
Geologische bibliografie van Nederland196342(7)
Some geological observations on the coast of Crete1963Boekschoten, G.J.42(8)Several features of Cretan beaches are described. Some instances of the influence of recent tectonic movement are given. The advent of volcanic material from Santorini on Cretan beaches must have happened quite recently. Beachrock formation is due to mixing of calciferous fresh-water with alkaline sea-water in beach sands. Density currents create a suitable hydrological background for beach sand cementation. Solution basins of 50 cm diameter and 5 cm depth are formed in limestones within a period of 1500 years. Aquafacts and ventifacts from the Cretan coasts are described.
Conodonts of Upper Devonian and Lower Carboniferous age from Southern Portugal1963Boogaard, M. van den42(8)Conodonts were found in samples from limestone outcrops in the Baixo Alentejo, southern Portugal; five samples from outcrops in the Pomarão region and two samples from a limestone-quarry near Carvoeiro, north of Mertola. (See maps fig. 1). The conodonts from the limestones of the Pomarão area belong to the uppermost Platyclymenia- and lowermost Gonioclymenia-stage, Upper Devonian; those from the Carvoeiro limestone to the Pericyclus-stagg Lower Carboniferous. Some new forms are described.
Twee zeventigjarigen en hun gedenkboek196342(8)
In memoriam Prof. Dr. Th. H.F. Klompé196342(8)
Gouden Doctoraat Dr Schurmann196342(8)
De losvloer van schacht IV van Staatsmijn Hendrik - Algemene richtlijnen voor het ontwerpen van losvloeren, leidende gedachten bij het ontwerp voor Staatsmijn Hendrik. Bijzonderheden over de uitvoering, speciaal wat betreft de automatisering1963Clercq, H. le42(9)
De toepassing van gesloten radio-actieve bronnen voor bedrijfscontrole in mijnen en bovengrondse werken1963Dijkstra, H.; Steur, C.42(9)A survey is given of the background-knowledge, necessary for the application of closed radio-active sources in the mining-industry. Several methods of measurement and control in use at the Staatsmijnen collieries are mentioned and shown by diagram or photograph. A suggestion is made of a method for sorting tubs, loaded with stone, loaded with coal, or empty.
Elektronische rekenmachines in het mijnbedrijf1963Knoester, C.J.42(9)
In memoriam Prof Dr. Ir. C. Schouten1963Engelbert; van Bevervoorde, W.F.C.42(9)
Observations on sedimentology and geomorphology of the Guadalete drainage area (Cádiz, Spain)1963Mabesoone, J.M.42(10)The W part of the Subbetic region in the province of Cádiz is drained by the Guadalete river. The area consists of sediments ranging in age from Triassic to Recent. The chief alpine orogenic phase which affected this region took place after the deposition of the Oligocene sediments. The Miocene shows only slight undulations, and in the younger deposits only evidence of tilting towards the W could be demonstrated. The river Guadalete flows through a mountain area as for as Puerto Serrano; from there it winds through a syncline in the Miocene deposits almost to the Loma del Torno. Finally, it flows towards the sea through a wide valley which was drowned several times during the Pleistocene transgression stages. The first river terraces begin to appear S of Puerto Serrano. Three levels (30-40, 15-20, and 2-5 m) can be distinguished. Sedimentological analysis of their deposits point to: (1) a shaping of limestone pebbles strongly influenced by a local supply of fresh material; (2) a content of rounded-brilliant quarz sand grains determined by the content of these grains in the underlying deposits; (3) a grain size of the finer part of the terrace material that also depends on the underlying sediments. The modern river-bed has the same characteristics with one exception: the grain size of the river-bed sands becomes generally finer downstream, but coarser particles are mixed with the finer type where the river passes through a gorge in the lower valley area. Furthermore, the deposits have a bi-phasic character with a fairly high silt-content. Heavy mineral distributions in the terrace as well as in the river-bed sediments show that the Guadalere supplied a characteristic association to the area. The older deposits, those of the Villafranchian included, have an EGA-distribution (epidote-garnet-andalusite) but the river deposits show an EZG-distribution (epidote-zircon-garnet). The latter association must thus be due to a supply from the source area, upstream from Puerto Serrano. The heights of the terrace remnants above river level and their situation permit the drawing of the following conclusions: (1) during its HT-time the river had a somewhat more easterly course than it has at present; (2) a slow tilting of the area caused the slipoff towards the W; (3) the length slopes of the Pleistocene river courses are steeper than the present one, causing a dipping of the terraces below the modern river plain. Some special features are also discussed, such as the gorge near Bornos, the intrenched meander of Arcos, and the cut-off meander near Jerez. The recent filling-up of the estuary is briefly explained. It appears that the Guadalete filled up the northern marsh part, that the sea filled the southern part with reworked deposits from the adjacent land, and that the environment has always been marine to brackish.
Permian near Wadi Araba eastern desert of Egypt1963Schürmann, H.M.E.; Burger, D.; Dijkstra, S.J.42(10)
Het carboon in de ondergrond van Nederland en de oorsprong van het massief van Brabant 1963Patijn, R.J.H.42(11)
De vorming van aardgas ten gevolge van nainkoling in het noordoosten van Nederland1963Patijn, R.J.H.42(11)
A recent dicovery of Itaberite in southern Surinam1963Ornstein, M.A.M.; Haug, G.M.W.42(11)
Convolute lamination, metadepositional ruptures and slumping in an exposure near Pobla de Segur (Spain)1963Nagtegaal, P.J.C.42(11)This paper presents the results of a comparative study of convolute lamination, metadepositional rupture, and slumping. The observations concern one exposure near Pobla de Segur (Spain), where these three types of sedimentary structures are equally well developed. The exposed rocks consist of a regular alternation of Upper Cretaceous, mostly graded, carbonate-rich siltstones and shales. The type of grading and the presence of a certain percentage of allochtonous material point to deposition of the siltstones by turbidity currents. Field observations, laboratory analyses, and mutual comparison of the structures suggest that in this exposure the convolute lamination, metadepositional rupture, and slumping have a common origin. Strongly dependent on the mineralogical composition and grainsize of the sediment as well as the various states due to differences of moisture content, these structures are the diverse results of gravity-induced, Iateral movements during and shortly after deposition. Many samples from the exposure were ground in order to approximate the original sediment. Thixotropy tests of these powders support the conclusions.
In memoriam Prof. ir. C.L. van Nes1963Seldenrath, T.R.42(11)
Einleitung zur informationstagung auf dem gebiete der Grubengasbekaempfung1963Hellwig, F.42(12)
Het ontstaan en het vrijkomen van mijngas1963Linsel, E.42(12)
Mijngas en ventilatie1963Maas, W.42(12)
Strahlausbreitung vor ort bei blasenden Sonderbewetterungsanlagen1963Renner, K.42(12)
Grubengasbekaempfung durch aufspueren1963Vergeron, M. de42(12)
Bestrijding van gasuitbarstingen1963Stassen, P.; Vandeloise, R.42(12)
Three examples of periglacial solifluction in the southeastern plateau Central France1964Rutten, M.G.43(1)Three examples of periglacial solifluction in the Velay (France) are described. The difference between primary basaltic scoria and the same material resedimented through solifluction; the difference between phonolitic periglacial block fields and present day phonolitic block scree; and the difference between older and younger solifluction deposits at the Issarlès Maar are studied.
Evidence of "Late" Alpine overthrusting, in the region NW of Lijar, Sierra de Los Filabres (SE Spain)1964Voet, H.W.43(1)To the north-west of Lijar "abnormal" tectonic successions are exposed, caused by relatively late thrusting. Elements of a Nevado-Filabride unit with a medium grade of alpine metamorphism are found overlying Alpuiarride elements showing a low grade of alpine metamorphism, the separating thrust planes being subhorizontal. Within a restricted area the following succession is found (from bottom to top): Nevado-Filabride mica schists and marbles – Alpujarride phyllites - Nevado-Filabride "older schists", mica schists and marbles - Alpujarride phyllites - Nevado-Filabride marbles.
Stichting voor isotopen-geologisch onderzoek1964Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.43(1)
Ter herdenking Ir. L. W. Leyds1964Schieferdecker, A.A.G.43(1)
In memoriam Prof. Dr. G.L. Smit Sibinga1964Simons, A.L.43(1)
Notulen Ledenvergadering Dec 1963 Genootschapszaken196443(1)
Zur tektonischen synthese der Ost- und Westalpen nach 60 jahren Ostalpiner Deckentheorie1964Wunderlich, H.G.43(2)
The function of geology in petroleum production1964Dikkers, A.J.43(2)
Voorwoord, speciale uitgave professor Dr. Mr. F. Florschütz1964Vlerk, I.M. van der; Hammen, T. van der; Zagwijn, W.H.; Heyst, F.J.J. van43(3)
Bibliografie professor Dr. Mr. F. Florschütz196443(3)
Un gisement du pléistocène inférieur aux environs de Bordeaux les Argilles de Bruges (Gironde)1964Balland, R.43(3)
Étude stratigraphique et paleogéographique du gisement de Mammiferes fossiles Pléistocène moyen de Solilhac près le Puy-en-Velay (Haute-Loire), France1964Bout, P.43(3)
Results of a pollenanalytic investigation in the untersee near Lunz in Austria1964Burger, D.43(3)The Untersee pollen diagram was derived from a boring in the Untersee near Lunz. The geomorphological features of the area are briefly described. The pollen diagram pictures the vegetational history of an epoch that covers a good deal of the Lateglacial and nearly all of the Holocene. The section begins with a sterile glacial clay, that changes into stratified (varved?) clay at the beginning of what we assume to be the Bölling interstadial. During the Alleröd interstadial a brown organic calcareous mud was laid down. The boundary with the Holocene is marked by an abrupt change of the sediment into a lime gyttja. The formation of peat in the upper part of the section commenced some 3000 years ago during the Subatlantic. The Younger Dryas and possibly the lowermost part of the Holocene are missing because of a disturbance in the sedimentation. Palynologically the Holocene is developed quite traditional, and the Alleröd (established by radiocarbon dating GRN 2406) and the preceding Older Dryas are clearly discernable. The assumed Bölling oscillation shows a double-topped curve, and the corresponding part of the section exists of some 600-700 (varve) stratifications. This could point to a passage of an equal number of years, which is in agreement with the duration of the Bölling time.
Results of a pollenanalytic investigation in the untersee near Lunz in Austria1964Burger, D.43(3)Enclosure B
Grèzes, litées et bancs de neige1964Guillien, Y.43(3)
A pollen diagram from the Quaternary of the Sabana de Bogotá (Colombia) and its significance for the geology of the Northern Andes1964Hammen, T. van der; Gonzalez, E.43(3)A provisional pollen diagram is presented from 200 m of lake deposits and peat from the Sabana de Bogotá (Colombia, South America), at an elevation of about 2600 m. It represents the major part of the Quaternary (fig. 3). The sedimentation must have started shortly after the upheaval of the Northern Andes. In the lower part the vegetation is poor in species, but gradually new types appear. Part of them (Alnus, Quercus etc.) entered this part of the Andes from the North (fig. 2). A clear zonation can be established (fig. 1), giving a clue for the dating and correlation of terraces in the region. A partly tentative correlation is given of the glacials and interglacials with those of Europe (fig. 1). The upheaval of this part of the Andes must have taken place at the very beginning of the Pleistocene or somewhat earlier, in the Pliocene.
Estudio palinológico de la turbera de estany (Olotm Gerona)1964Menéndez Amor, J.; Amorós, J.L.; Galván, J.43(3)
A pollen diagram from equatorial Africa Cherangani, Kenya1964Zinderen Bakker, E.M. van43(3)The pollen diagram of a swamp, 3.70 m deep, and situated at an altitude of 2900 m in Kenya has been studied. The swamp is at present surrounded by the uppermost montane forest. The diagram shows that the tree-line was much lower down in former times and a number of climatic zones could be inferred from the diagram. A C-14 date of 12,650 ± 100 B.P. (GRN 3048) obtained from the 2.85-3.00 m level enabled the author to calculate the age of these climatic zones. At the dated level, which is contemporaneous with the Oldest Dryas time (compare: Radiocarbon dates K-544, K-545,K-546), the climate has been cold and dry. All the zones correspond remarkably well in age and temperature characteristics with those of the European chronology from the Pleniglacial B of the Würm onward. Only the Bölling Interstadial has not yet been recognized. The close correspondence with the study of v. d. Hammen and Gonzalez in Colombia (1960 a,b) is apparent (Table I). The results prove again that the temperature fluctuations during the Quaternary were of cosmic origin. The Pluvial theory for Africa as well as the ecology of plants, animals and man will have to be studied in this continent against the background of the European temperature chronology. The Gamblian Pluvial was contemporaneous with the Würm Glacial and represented a hypothermal period in Africa. The objection that movements connected with the Rift valley could have caused the climatic changes can be ruled out as the climatic correlation with Europe is too convincing in detail to be casual.
Problemen van de geotektoniek1964Sitter, L. U. de43(4)
Uitreiking van de van Waterschoot van der Gracht Penning aan Dr. Ir. W. P. van Leckwijck196443(4)
Palynologial data on the age of the bauxite in British Guiana and Surinam1964Wijmstra, T.A.; Hammen, T. van der43(4)
On the tectonics of the Sulcis area, S. Sardinia1964Poll, J.J.K.; Zwart, H.J.43(4)
KNGMG Jaarverslag 1963196443(4)
Geomorphology of the surroundings of Kuantan (Eastern Malaya)1964Nossin, J.J.43(5)The area discussed is located in eastern MaIaya, bordering the China Sea (fig. 1). The morphological aspects are shown in fig. 2. Under the hot and humid climate with strong monsoonal influence, rocks undergo a deep and intense weathering. A biotite granite and an olivine basalt from the majority of the country rock. The granite weathers into an unsorted mass of sand and clay which is subjected to strong mass movements in spite of the dense vegetation. During colluviation, silt is washed out leaving the colluvium as a bimodal deposit. The granite landscape exhibits lateral planation from the base, resulting in comparatively flat piedmonts surrounding steep hills. Both carry a thick residual cover. Granitic colluvium occurs on the piedmonts as well, and also occupies large parts of the surrounding sedimentary flats. The basalt weathers into a heavy homogeneous clay which undergoes little or no mass displacement and produces a basically different landscape. It is lower and flatter than the granite zone and densely dissected by a dentritic network of insequent streams with steep valley-sides and heads. Other rocks and their weathering products are of subordinate consequence in this area. The coast is lined by a series of beach ridges which are Holocene of age. Between the higher land and these beach ridges large flats were filled in with fluvial and swamp deposits after the closure of the bars. The drainage on these flats is largely impeded and frequent shifts have occurred in the fluvial pattern. The beach ridges blocking the drainage system force rivers to converge upon common outlets; parts of the swamps have thick peat layers. The fluvial deposits have a remarkably high silt contents, much of which is supplied by washing-out from the granite colluvium. Seasonal changes in transportive capacity of the rivers cause bimodal grain size distribution in many of the fluvial sediments. Earlier workers postulated a Holocene tectonic uplift of eastern Malaya. A discussion of evidence points out that no such uplift has taken place, but that the relative fall of sea level during the Holocene has been eustatically caused. An examination of ancient maps may support the submission that the southern part of this area was only converted into land after 1800 A.D.
Paleomagnetic research in the Netherlands1964Rutten, M.G.; Veldkamp, J.43(5)Since 1956 paleomagnetic research is carried out in co-operation between geologists of Utrecht university and geophysicists of the Royal Netherlands MeteoroIogical Institute in De Bilt. A number of studies on rock magnetism has been published on Iceland (Rutten and Wensink, 1959, 1960, a, b), Norway (van Everdingen, 1960), Germany (Nijenhuis, 1961; As and Zijderveld, in press), France (Den Boer, 1957; As and Zijderveld, 1958; Kruseman, 1962), Spain (van der Lingen, 1960; Schwarz, 1962, 1963) and Italy (Rutten, 1959; Dietzel, 1960; van Hilten, 1960, 1961, 1962b; de Boer, 1961). The position of the magnetic pole for these countries has been studied from rock samples of Paleozoic to Quarternary age. Special attention has been paid to the magnetic cleaning of the samples. A method of cleaning was developed by As and Zijderveld (As and Zijderveld, 1958; As, 1960), in which the remanent magnetization is observed after exposing the sample to alternating fields of increasing strength. This makes it possible in many cases to remove the unstable part of the magnetization, while saving a good deal of the more stable remanent magnetism which is supposed to have been induced during the geneses of the rocks. The special point in this method is that not only the intensity but also the direction of the magnetization is studied. It is found that the behaviour of the direction of the remanent magnetism during stepwise demagnetization is of greater importance than its intensity. To test the secular variation in the geologic past, Wensink and collaborators and Hantelman are studying continuous sections of lava flows in Iceland, respectively from the Plio-Pleistocene and from the earlier Tertiary. The variation is as large as in recent times; the magnetic dipole axis is found to be wandering up to 30° of the axis of rotation. In Permian ignimbrites, both from the Oslo Graben and from northern ltaly, the secular variation seems, however, to have been much smaller, a difference requiring more research. Paleomagnetism is used as a tool in many geologic field studies. In Iceland in this way a detailed stratigraphy of basalt flows and intercalated tillites has been built up. This leads to an analysis of the tectonics of the Central Graben, whilst it also proves the existence of widespread glaciation already during the Pliocene. In southern Europe the pole positions belonging to the Permian of the Alpine foldbelt are found to be consistently aberrant from those of "Meso-Europe". Large scale crustal drift must have occurred in the Tethys during the Mesozoic. Movements of up to about 5000 km have been postulated, far exceeding those needed by the most nappist of alpine tectonicians.
Rejuvenation of Pre-Cambrian rocks under epirogenetical conditions during old Palaeozoic times in Africa1964Schürmann, H.M.E.43(5)An international team produced 30 isotope age determinations of various Pre-Cambrian rocks and minerals from the Northern part of the Eastern Desert of Egypt, surprisingly showing - With a few exceptions of about 650 m.y. - Palaeozoic ages (500-550 m.y.). Fortunately fossil-bearing Lower Cambrian has been established lying flat and unconformably over Pre-Cambrian. As two major unconformities exist between the Pre-Cambrian proper and the Lower Cambrian (firstly, Hammamat series with boulder beds composed of Pre-Cambrian igneous and secondly Lower Cambrian unconformably above Hammamat series) one had expected an isotopic age of 600-1000 m.y. for the igneous of the Pre-Cambrian. In the Red Sea area no folded Cambrian and no cambrian orogeny has been proven; only epirogenetic tectonics exist. This also holds good for East and South Africa, where no fossil-bearing Cambrian has been established as yet, but where similar yound isotope ages if igneous rocks are available. As explanation one could take into consideration the possibility of rejuvenation of young Pre-Cambrian rocks of the crust in Palaeozoic times due to rising convection currents increase in temperature, tension and epirogeny (taphrogeny), the major tectonic feature along the Red Sea and in East Africa.
Enkele opmerkingen over kalkzandsteenbanken in het preglaciaal van Midden-Nederland1964Crommelin, R.D.43(5)
Interpretation of the wandering paths of ancient magnetic poles1964Hilten, D. van43(6)Polar wandering paths have been constructed for imaginary continents performing simple drifting movements. The effect of both continental drift and polar wandering upon the shape of the polar wandering paths are analysed. The results have been compiled in the final section of this paper. The often-heard assumption that polar wandering paths should coincide when the corresponding continents are replaced in their original, pre-drifting configuration is only partly correct. A method is given to determine besides the ancient latitude also the relative longitudinal positions of continents from their paleomagnetic data.
The method of statistical structural analysis (as applied to the crystalline basement of the Dolomites in North italy)1964Agterberg, F.P.43(6)The structure of the crystalline basement of the Dolomites can be divided in (1) a more regional Hercynian structure including almost all major and minor folds, and (2) a number of local Alpine structures which are disturbing the Hercynian strucure. The Alpine deformations consist of lateral compression structures in the S. Stefano and Pusteria areas, respectively northeast and north of the Dolomites, and probably some rapid increments in thickness of the crystalline rocks in the Cima d'Asta and Gosaldo areas south of the Dolomites. The Hercynian minor folds in the S. Stefano area have been refolded into an anticlinal structure with a southeast directed Alpine axis. The limbs of this anticline have been rotated with respect to each other along the axial plane. The amount of rotation is locally as high as 63°. This large shearing movement took place during Alpine orogeny. The Alpine deformation is also found in the adjacent permian beds overlying the prepermian erosion plane. Similar conclusions can be drawn with respect to the Pusteria area. The regional schistosity of the Cima d'Asta and Gosaldo areas is probably subparallel to the prepermian erosion plane. Variations in the mean strike of this schistosity demonstrate that there are locally rapid increments in thickness in the crystalline rocks south of the Dolomites. A new explanation for this phenomenon is proposed. The regional schistosity in the Gosaldo area is generally a secondary schistosity. Distinction between primary and secondary schistosity cannot be made in many localities. However, the undefined schistosity planes show a mean attitude that, in terms of Student's t-test, cannot be distinguished from the mean attitude of the well-defined secondary S-planes in other localities. The combined groups of S-planes are thus homogeneous from a statistical point of view. This conclusion is not in disagreement with the fact that the stratification in the crystalline rocks and the enveloping contour of many Hercynian minor folds (equivalent to D'Amico's S1) make different angles with the regional schistosity.
Petrography and tectonics in the Agordo-Cereda region (Crystalline of the Southern Alps)1964D'Amico, C.43(6)A stratigraphic series of epizonal metamorphic rocks can be recognized in the Agordo-Cereda region (crystalline of the Southern Alps); the metamorphic grade increases toward the deepest portions of this series. Tectonically, two sets of different S-surfaces are to be distinguished (S1 and S2). Agterberg's tectonic interpretation of the region is discussed and rejected. Some large changes of volume are postulated by that author as a consequence of the alpine movements: however, they are not supported by petrographic evidences. Some assumption are implicit in the statistics of the tectonic measures as considered by Agterberg i.e.: Hercynian deformation was homogeneous all over in the region; S1 and S2 are parallel; S of the metamorphic rock and S of the Permo-trias are parallel. These assumptions are not correct. The tectonic interpretation of other crystalline regions in the eastern Southern Alps, as made by Agterberg, is also called in question.
The Hexhlet instrument for dust determinations1964Matla, W.P.M.43(6)
In memoriam Prof. Dr. Ir. C.H. Edelman, M.I.1964Doeglas, D.J.43(6)
Internationale hydrologische bibliografie1964Tromp, N.W.43(6)
Hypothèses concernant la position des unités structurales et paléogéographiques de la transversale Jaén-Grenade (Andalousie)1964Busnardo, R.43(7)
Sur les rapports entre les zones Prébétiques et subbétiques entre Cazorla (Prov. De Jaén) et Huéscar (Prov. De Grenade, Espagne)1964Foucault, A.43(7)
Mise au point sur l'âge des phenomènes tectoniques majeurs dans les Cordillères Bétiques occidentales1964Chauve, P.; Didon, J.; Magne, J.; Peyre, Y.43(7)
Problemes structuraux dans le domaine Alpujarride au sud-ouest de la Sierra Nevada1964Boulin, J.43(7)
Ein Querschnitt durch die Betischen Kordilleren bei Ronda (SW Spanien)1964Hoeppener, R.; Hoppe, P.; Dürr, S.; Mollat, H.43(7)In fünf Abschnitten wird ein Querschnitt durch die westlichen Betischen Kordilleren beschrieben2. In der "Einführung" geben wir einen Überblick über die verschiedenen Einheiten, die in diesem Raume unterschieden werden können und weisen auf ihre Beziehungen zu Einheiten der zentralen und östlichen Betischen Kordilleren en sowie zu den Einheiten des Rifs in N-Afrika hin. Im zweiten Abschnitt, "Der Norden", steht die stratigraphisch-fazielle Entwicklung im Subbetikum und im Penibetikum im Vordergrund der Betrachtung. Das gegenseitige Verhältnis dieser beiden Einheiten wird diskutiert. "Die Mitte" umfasst die Front der Betischen Decken mit ihrer Vielfalt von Einheiten z.T. filabridisch-alpujarridischen Charakters. Die Beziehungen dieser Decken zu ihrem Vorland legen die Deutung nahe, dass die Sedimentationsräume der Decken südlich an die des Vorlandes anschlossen. Der Bereich der Mittelmeerküste, "Der Süden", erfährt eine neue Aufgliederung. Die stratigraphische Stellung der z.T. hochmetamorphen Gesteine und ihr Verband mit den basisch-ultrabasischen Massiven wird untersucht. Im "Ausblick" werden die wichtigsten Ergebnisse zusammengefasst und die Deurungen diskutiert, die die geologische Situation den Bearbeitern nahelegte.
Speculations based upon a comparison of the stratigraphies of the different tectonic units between Vélez Rubio and Moratalla1964Gillavry, H.J.M.43(7)A comparison of stratigraphic successions of different tectonic units along the meridian Vélez Rubio to Moratalla has failed to disclose obvious indications for a tectonic reversal of the original geographic arrangement. The hypothesis of deposition of Betic of Málaga upon the South flank of a Subbetic basin is considered and the logic consequences are examined. The zone of outcrops of the Betic of Málaga, from Sierra de Espuña through Vélez Rubio and perhaps to Málaga, would be subautochthonous. The proved extent of the Betic of Mãlaga nappe would be restricted. At least three major phases of movement are envisaged: 1) an early Oligo-Miocene nonhward thrust of the Alpujarrides, 2) a later Oligo-Miocene southward nappe-movement of the Betic of Málaga, and 3) a Miocene northwest thrust of northern Subbetic over Prebetic. The main axis of compression would have moved episodically northward.
Zur Gliederung des Jungtertiärs im Becken von Vera, Südostspanien1964Völk, H.R.; Rondeel, H.E.43(7)Eine jungtertiäre Schichtfolge wird lithologisch gegliedert und kurz beschrieben. Dabei wird vor allem ein älterer und ein jüngerer Anteil unterschieden; beide sind durch Lithologie und tektonischen Stil gut charakterisiert.
Distinct phases of Alpine overthrusting and subsequent thrusting in the Eastern part of the Betic zone of Spain1964Egeler, C.G.; Bodenhausen, J.W.A.43(7)The large scale horizontal translations in the eastern part of the Betic zone are ascribed to at least two distinct phases of overthrusting. It is emphasized that the later of these phases has been responsible for important changes in the original superposition of the major units in the deeper part of the orogene. This is illustrated by the widespread occurrence of "abnormal" tectonic successions, especially in the northern parts of the Sierra de los Filabres. The effects of subsequent folding and steep thrusting can be seen throughout the Betic zone to be superimposed on the overthrust structures. Cross-sections through the Sierra de las Estancias clearly illustrate the resulting imbricate patern.
On the stratigraphy of the Nevado-Filabride units as exposed in the eastern Sierra de Los Filabres (SE Spain)1964Nijhuis, H.J.43(7)
Essai de corrélations des unités Bétique dus la transversale de Lorca - Aguilas1964Fernex, F.43(7)
The Almagro unit: a new structural element in the betic zone?1964Simon, O.J.43(7)Recent investigations in the Sierras de Almagro and de Enmedio, situated in the south-eastern part of the Betic Cordilleras, have revealed the presence of a unit - named the Almagro unit - which tectonically underlies rocks of the Alpujarride complex and the Betic of Málaga. Several hypotheses are discussed-with regard to the zone of deposition of the rocks of this Almagro unit. At this stage of investigations the author favours the view that they were deposited to the north of the Nevado-Filabride complex. According to this line of thought the Almagro unit would represent a new structural element in the Betic Zone s.s. It is stressed, however, that further detailed investigations will be necessary to check this working-hypothesis.
Schatting van de maximale diepte van de bron van een warmtestroomanomalie1964Collette, B.J.43(7)
Experimentele metamorfose1964Schuiling, R.D.43(7)
Activiteiten in 1963 van de "commission on new minerals and mineral names" van de "International mineralogical association" 1964Roever, W.P. de43(7)
De vlekken in de vlekleien van steige (Vogezen) en Vogtland (Saksen)1964Bosma, W.43(7)
On the establishment and activity of the provisional commision on the genesis of ore deposits1964Kutina, J.43(7)
De veiligheidscongressen Aix-les-Bains 1963 en Salzburg 19631964Maas, W.43(8)
An interesting pegmatite deposit in Northeastern Surinam1964Montagne, D.G.43(8)A description is given of a small complex Li-Ta-Sn pegmatite in heavily weathered prae-Cambrian rocks near the Marowijne River in Northeastern Surinam. Detailed exploration was carried out during a pilot exploitation of amblygonite and tantalite/cassiterite. The often enormous masses of amblygonite are conspicuous (up to at least 8 m). The absence of lepidolite and the great uncertainty about the presence of spodumene are also remarkable. The geological setting is mainly controlled by faulting. Heavy chemical weathering severely hampered the study of the internal structure. A two-staged genesis of the pegmatite is tentatively suggested
Ancient and recent turbidites1964Bouma, A.H.43(8)Ancient turbidites are characterized by a single facies model which is composed of five intervals in a fixed succession. Each interval contains one dominant sedimentary structure. The intervals are from bottom to top: graded interval, Iower interval of parallel lamination, interval of current tipple lamination, upper interval of parallel lamination and pelitic interval. Most of the turbidite layers do not have this complete succession of intervals, but only part of them without changing the order of the intervals. Investigations by means of radiography in deep-sea sands from submarine canyons and adjacent troughs have been carried out so as to compare these sands with the facies model of ancient turbidites. It appears that recent turbidites containing the turbidite facies model, can only be found on the outer part of the canyon fans and in the throughs.
Graptolites in the "Tibetan zone" of the Nepalese Himalayas1964Strachan, I.; Bodenhausen, J.W.A.; Booy, T. de; Egeler, C.G.43(8)
A contribution to the sedimentary petrolohy and provenance of young Pleistocene cover sand in the Netherlands1964Crommelin, R.D.43(9)The aim of the investigation was to examine the mineralogy of Young Pleistocene cover sands as related to their depositional environment and more specifically to study the interrelationship between subsurface, Older and Younger cover sand in terms of heavy mineral composition. 75 profiles over the total cover sand area of the Netherlands were sampled in pairs. Heavy mineral analysis was confined to the 210-150 micron fraction so as to minimize confounding provenance and grain size effects. The results permit a subdivision into three distinct regions, each showing a characteristic heavy mineral composition which moreover appeared to be closely related to the mineralogy of the subsurface. Hence a more or less local provenance of the cover sand formation is advocated, "local" being taken in the opposite meaning to "conveyed over a long distance" as would be the case if the North Sea Basin for example, was taken as the source area. The relation between Older and Younger coversand was tested by the two-way analysis of variance method' It was found that within the three cover sand regions there is often a very significant locality contrast, whereas the stratum contrast is usually not significant. This brings us to the concept that local reworking of Older cover sand gave rise to Younger cover sand, whereas the absence in most cases of significant mineralogical changes when passing from Older cover sand to Younger cover sand usually indicates that no systematic agents were active in this process. Finally some remarks are made on the effect of the "closed-array system" on variables of constant sum, a frequent condition in sedimentary petrology to which Chayes has recently called attention and which is indirectly connected with the present problem.
Secular variation of Earth magnetism in Plio-Pleistocene basalts of Eastern Iceland1964Wensink, H.43(9)Oriented samples of Plio-Pleistocene basalts were collected in Eastern Iceland for a paleomagnetic investigation. Pole positions were determined for successive individual flows. These show an irregular course which can be explained as a result of the secular variation of the earth magnetism. The stratigraphical succession consists of the paleomagnetic series N2 and R1. In both series a maximum of three basalt flows is intercalated with an inverted direction of. magnetization. These flows, nearly always accompanied by tillites and also by tuff breccias and globular basalts, have a wide distribution E of the Central Icelandic Graben, but were not found at its western side. The remanent magnetization of these flows may be explained either as a result of self-reversal or of induction from older lavas.
Netherlands Mesozoic committee196443(9)
Secundair vervoer in een kolenmijn1964Goderbauer, L.43(10)In dit artikel worden behandeld de verschillende aspecten die met het ondergrondse materiaalvervoer samenhangen. - Allereerst wordt het begrip secundair materiaalvervoer omschreven, als zijnde het materiaalvervoer in de kolenafdeling. - Vervolgens wordt het belang van het secundair materiaaltransport nader toegeÌicht, waarbij blijkt dat de kosten van het totaal vervoer ondergronds op circa 8-11 gld per ton neerkomen, terwijl de kosten van het materiaalvervoer circa. 4 à 5 gld per ton bedragen. - Daarna worden enige belangrijke aspecten van het vervoer belicht, zoals de economische kant, de wijze van aanlevering der materialen en de naar de tijd geregelde voorziening van de pijlers. - De verschillende vervoersmethodieken, zoals: sleepbak, monorail, bandvervoer enz. worden bezien naar hun systematiek, de inzetcondities en de transportmogelijkheden. - De vervoersorganisatie wordt qua opzet, beoordeling en haar mogelijkheden in ogenschouw genomen. - Tenslotte worden enige resultaten en gevonden betrekkingen weergegeven die op de mijnzetel Oranje-Nassau II zijn gevonden. Als conclusie kan worden vermeld: - dat het materiaaltransport in relatie tot de kostprijs, van dusdanige importantie is, dat hieraan ruime aandacht moet worden geschonken; - dat de keuze der middelen bepalend kan zijn voor de te bereiken mogelijkheden; - dat tijdige planning en ingepaste werkvoorbereiding der ondergrondse werken eveneens van doorslaggevend belang kan zijn t.a.v. de later te bereiken resultaten; - dat de organisatie wel het belangrijkste aspect is ter bereiking van optimale resultaten; - dat een regelmatige beoordeling van de resultaten enerzijds en het beschikken over een groep arbeidsanalysten anderzijds noodzakelijk is om steeds bij te blijven. Verder zij opgemerkt dat de monorailinstallatie niet alleen als vervoermiddel, maar ook als hulpmiddel bij het verplaatsen over korte afstanden van allerlei materiaal, bij de voorbereiding en bij de winning van groot belang is en dat zij ook daar haar nut heeft bewezen. Tenslotte moet nog worden opgemerkt dat niet uit het oog mag worden verloren dat de resultaten bereikt met de invoering van het monorailtransport of een verbeterd sleepbakvervoer niet uitsluitend ziin terug te vinden in de cijfers van het vervoer als zodanig. Het hele bedrijf vormt uiteraard een harmonisch geheel, waardoor de verbeteringen op andere plaatsen ten goede komen aan het monorailvervoer, terwijl anderzijds verbeteringen die bijv. het monorailvervoer mogelijk maken, eveneens doorwerken in andere sectoren van het bedrijf. Hierdoor is het noodzakelijk dat het vervolg van de harmonisering van de rationalisatie-aanpak ook in de komende jaren met gelijke interesse, belangstelling en daadkracht wordt voortgezet ter verkrijging van een optimaal rendement ondergronds.
Cross-stratified units, some with silt bands, in the Folkestone beds (Lower Greensand) of Southeast England1964Allen, J.R.L.; Narayan, J.43(10)Cross-stratified units in the Folkestone Beds (Lower Albian) of the English Weald have foresets, graded from fine up into coarse, showing either abrupt or tangential contacts with the bases of the units. When the contact is tangential, thin silt bands may occur between groups of sandy foresets and bottomsets. The bottomsets then commonly show small-scale asymmetrical ripples and cross-stratification indicating currents in directions opposite to those which formed the larger foresets. Studies in a laboratory flume show that these features are consistent with the interpretation of the crossstratified units in terms of the migration of large-scale ripples in a shallow sea, under tidal conditions. Those units with silt bands could represent ripples moved only during storm conditions, when the normal tidal flows were enhanced by wind-induced currents.
Modderkogels, mergelconcreties of askogels van Krakatau1964Faber, F.J.43(11)Some volcanoes, although they are by no means "mud volcanoes", have erupted "mud balls", usually with a diameter of 0.5 to 1.5 cm, but there are specimens known of 7 cm. They are almost perfect spheres. Mud balls, found in and near the Indonesian volcanoes of Tankuban Prahu and Kawah ldjen, were described by Stehn (1932). Smaller mud pellets are also collected near many other volcanoes. The large mud balls (sometimes called ash balls) are also known as accretionary lapilli or -pellets, as they have a composition of concentric layers. The smaller pellets may have been formed by isolated raindrops on dry ash, as already Poulett Scrope (1829) pointed out, and recently again Miura (1959) in Japan, but for the bigger specimens Miura (1959) in Japan, but for the bigger specimen this explanation is not applicable. For them the hypothesis presented by Stehn (1932) is accepted, summarized in the Nomenclature (Schieferdecker, 1959), under number 4225. The spherical mud balls, composed of concenric sheils of volcanic ash are formed around a grain of sand or a lapillo and originated during prolongated rotation in whirling eruption clouds. In the literature the occurence of mud balls with a diameter of more than one or two centimeter is rarely mentioned, which indicates that they must be rather scarce. A number of them is included in the Verbeek-Collection (Museum of the Technological University at Delft). Verbeek assembled them soon after the catastrophic eruption of 1883 at the Krakatao, the island volcano situated between the islands of Java and Sumatra in Indonesia. Also Escher collected many specimens; they are at present in the Rijksmuseum in Leiden. Verbeek (1885) in his famous treatise on Krakatao pays some attention to these remarkable products, and called them calcitic "concretions". Now in Verbeek's collection, there are indeed true concretions of a more or less spheric shape, and with dimensions of more than ore centimetre, but there are also other bodies, in the present treatise called mud balls. The true concretions show a layering parallel to a flat plane. They contain much CaCO3; this was also mentioned by Verbeek, see table. It is remarkable that the other bodies from Krakatao also have a high CaCO3-content, but they have indications of a concentric shell structure, and resemble very closely' the mud balls described by Stehn. The chemical composition of the Krakatao mud balls, however, is different from other mud balls, mentioned in the literature. The high CaCO3-content of the concretions may have augmented gradually arid they may have been formed (as Verbeek and also Escher suggested) in the sedimentary basement of the volcano. The occurrence, together with the mud balls with a high CaCO3-content, is a remarkable coincidence. Originally the concentric mud balls must have been in a position of accumulating a high CaCO3-content. They were formed during an eruption prior to that of 1883. It is assumed that at this time there has been a crater below the sealevel that may have been partly filled with CaCO3 containing mud. Finally, although there is a difference in chemical composition between Krakatao mud balls and those described by Stehn, I think they have the same genesis which may be sustained by the remarkable similarity in shape of some of the balls and tectites. This also points to an origin of the shape in the air, and not as a concretion.
The spots in spotted slates of Steige (Vosges) and Vogtland (Saxony)1964Bosma, W.43(11)New data are submitted about the genesis and the mineralogical composition of the spots in the spotted slates belonging to the well-known contact aureole in the Steiger Schiefer (Vosges). They are based on a comparative study of the spots in the spotted slates of Steige and of Vogtland (Saxony). The spots have been studied macroscopically as well as with the microscope and X-rays. The results indicate that the spots in the slates of both regions are pseudomorphs after cordierite. In the Vogtland slates relics of the characteristic twinning structure are often seen. Unaltered cordierite is generally only present in the hornfelses. The effects of contact metamorphism are discussed in relation with the theoretical temperature distribution around a cooling intrusive body.
De ,,Zone van Rosmalen"1964Zonneveld, J.I.S.43(11)De Ridder and Zagwijn (1962) described the "Zone of Rosmalen", a mixed Rhine and Meuse sediment of Holsteinian age in Eastern North Brabant. They supposed that this zone represents a gradual transition of the Formations of Sterksel and Veghel. In the course of the Holsteinian the influence of the river Rhine should have decreased gradually, the river Meuse gaining in importance. It is shown that this reconstruction cannot be in accordance with the reality: the Rhine did not flow continuous in the region under consideration ,the "Zone of Rosmalen" is merely the lower part of the Formation of Veghel in which sediments derived from the subsoil (consisting of older augite free Rhine sand) have been contaminated.
Geologische bibliografie van Nederland196443(11)
New facts on the geology of the "Young" unconsolidated sediments of Northern Surinam1964Montagne, D.G.43(12)A short synopsis is given of the most important data on the stratigraphy of the "young", unconsolidated sediments in Central Northern Surinam, as collected in recent years in and around the Billiton bauxite mines. Some information on heavy minerals, clay mineralogy and grain size distribution is added. A "standard Section" for the area is constructed and a new stratigraphical table is presented. Attention is called to the possible regional importance of some of the data presented.
New facts on the geology of the "Young" unconsolidated sediments of Northern Surinam1964Montagne, D.G.43(12)Plate II
The development of successive structures in the Devonian and Carboniferous of Devon and Cornwall1964Zwart, H.J.43(12)The structures in the Devonian and Carboniferous along the west coast of Devon and North Cornwall are described. The Devonian north of the Culm synclinorium contains steep cleavage-folds with E-W axes. In the northern part of the Culm measures vertical accordion folds occur. Farther south a second set, with E-W directed recumbent folds, deforms the first folds with a consistent southward overthrusting movement. South of Rusey Beach another kind of recumbent folding with N-S axes was found and on these, E-W recumbent folds are superposed. Here the first set constitutes the upper part of a metamorphic infrastructure and is accompanied by schistosity and extension in B. A possible link between the two sets of folds is proposed.
Gravimetrische stofgrenzen van het stofinstituut en Amerikaanse stofgrenzen1964Matla, W.P.M.; Terpstra, J.43(12)The gravimetrically-determined dust-limit values of the "Stofinstituut" and the .American dust limits published at the end of 1962 are first described. Both limit values can be represented by hyperbolic functions. With the aid of 133 dust measurements by gravimetric means and also by the American method with the midget impinger, carried out by the "Institut d'Hygiène des Mines" of the Belgian mining industry, it has been possible to compare the dust-limit values. It was found that for the given dust conditions both limits are the same.
Relatie tussen het kwartsgehalte en het asgehalte van pijlerstof1964Matla, W.P.M.; Terpstra, J.43(12)A large number of dust samples were taken in the various working operations in mining and the quartz and ash contents determined. The results of the analyses have been processed statistically. A clear relationship was found between the quartz and ash contents of the dust, so that the ash content is a good measure of the quartz content.
Coastal geomorphology of Eastern Nigeria: Beach ridge barrier islands and vegetated tidal flats1965Allen, J.R.L.44(1)The visible portion of the Niger delta consists, in eastern Nigeria, of three geomorphological units. Behind a chain of barrier islands formed of sand ridges of two types, occurs a broad tidal flat colonised by mangroves and marked by a reticulate drainage pattern. The tidal flat is succeeded inland by a forested river floodplain. The tidal flat is also partly in contact with a low terrace formed on Late Tertiary and possibly Pleistocene sediments. The nature of the barrier islands and the tidal flat is related to the forces at work in the region. The mangrove swamp of the eastern delta is growing at the expense of the barrier islands, the floodplain, and the terrace because of erosion in tidal channels. It is suggested that the reticulate drainage pattern of the tidal flat is due to the stabilizing of deposited sediment by the mangroves and the manner in which these plants grow collectively. The Nigerian barrier complex, situated in the tropics, is compared with the temperate tidal flats of the Dutch coast. The main differences depend on the contrasted role of plants in the two areas, and thus finally on climate.
Value of experiments in Geology1965Kuenen, P.H.44(1)
Palynological study of a very thick peat section in Greece, and the Würm-glacial vegetation in the Mediterranean region1965Hammen, T. van der; Wijmstra, T.A.; Molen, W.H. van der44(1)A pollen diagram from Macedonia, partly dated with C14, suggests dense oak-forests during the early Holocene and a steppe-like open vegetation during the Würm-glacial. As similar conditions were found elsewhere in the northern Mediterranean, we think no proper pluvial conditions prevailed in that area during the last glacial.
Recente mogelijkheden voor geologische luchtverkenning1965Poley, J.T.44(1)
The buried bauxite deposit of onverdacht, Surinam, South-America1965Aleva, G.J.J.44(2)Data arc presented about the buried bauxite deposit at Onverdacht, Surinam (in the Guiana Lowlands). The upper boundary of the bauxite layer is an old topographic surface with a consequent drainage pattern. The lower boundary shows many features of a sedimentary nature, indicating the contact between two sedimentary beds of different physical composition. Statistical work on SiO2 and Fe2O3 analyses of borehole samples is reported. The bauxite layer is formed by the bauxitization of a presumably arkosic or silty sedimentary bed, with a continued bauxitization at lower levels that attacked the underlying or intercalated kaolin. After having been buried by younger sediments, silica-rich solutions partly destroyed the top part of the bauxite bed. In principle, the bauxitization here was not different from that of most other bauxite deposits, viz. the extreme weathering and leaching of a pre-existing rock, the nature of this rock (igneous, metamorphic or sedimentary) being of no genetic importance.
Preliminary palynological study of hydrocarbons in Israel1965Horowitz, A.; Langozky, Y.44(2)
Thin sections for determination the composition of the light-mineral fraction of the unconsolidated sediments1965Vogel, D.E.44(2)Several ways exist for determining the composition of the light-mineral fraction of unconsolidated sediments. For not mounted samples: separation by heavy liquids, x-ray analysis, and the use of different immersion liquids; and for mounted samples staining with an organic dye, etching with HF and the use of the universal stage, These methods were investigated as to their suitability for exact sedimentpetrographical work but all were found to have limitations. A technique for making thin sections of unconsolidated sediments as described by Mamourofski and Samsonof was modified slightly and adapted to our needs. In the resulting slides the distinction of quartz from oligoclaseandesine proved to be quite easy. Moreover, the carbonate content of the sample can be retained because no treatment with HCI is necessary; if needed, subdivisions in the quartz- and rock-fragment groups can be made.
#REF!1965Harsveldt, H.M.44(2)
The curvature of the Antilles1965North, F.K.44(3)Geosynclinal belts of mid-Mesozoic, pre-Cretaceous age form much of the western edge of the Americas from Alaska to Baja California, and from coastal Peru to a point far south in Chile. They also appear in the curvilinear belt of the Greater Antilles, and in the row of islands off the north coast of South America. It is suggested that these orogenic sectors arose out of a compound geosyncline originally more or less straight, and that the violently convolute portion, from Guatemala to Puerto Rico and thence back to the Goajira Peninsula, has undergone progressively increasing northeasterly curvatute as a consequence of tangential migration. The migration is envisaged as being due tot the tangential "squeezing out" of a segment of the crust and subcrust, between the opposed rotations of two plates of continental dimensions: that of South America (rotating clockwise), and that of the North Pacific (rotating anticlockwise). Acting as a moving agent behind the migrating orogenic arc was a prong of old rock, still recognizable at the surface. This moving agent is compared with similarly recognizable prongs behind similarly arcuate orogens in the Himalaya and in the Alps. The tangential migration reached a limit with the impingement of the migrating arc against a stable foreland. The foreland is the old crystalline platform on which the Bahama Banks and the Lesser Antilles now stand. From the time of this impingement onward, deformation has been taken up by other means, developing on the one hand large sttike-slip fauits, and on the other great arcuate or linear downtucks of the oceanic crust. It is to these latter that the famous negative gravity anomalies are due. It is concluded that the ophiolitic belts on the two sides of the Caribbean are not likely to join in an arc around the eastern end. As both belts have undergone deformation in the same sense (from the south towards the north), they are more probably the dismembered halves of a single belt originally more or less straight.
Carboniferous (Westphalian) foraminifera from Abu Darag eastern desert, Egypt1965Omara, S.; Vangerow, E.F.44(3)Foraminifera from marine Carboniferous shales, intercalating the Nubian-type sandstones at Abu Darag, Eastern Desert, Egypt, fix the age of this section as Westphalian, viz. stratigraphically lower than the Wadi Araba section of Lower Stephanian age. The Abu Darag section occupies thus, an intermediate stratigraphic position between the Lower Carboniferous (Tournaisian-Visean) of southwestern Sinai, and the Lower Stephanian of Wadi Araba.
Hand-drilling tools for geological investigation1965Lammers, J.44(3)ln a flat country like the Netherlands field geologists have to rely largely on data derived from borings. As nearly the whole surface of unconsolidated sediments is of Quaternary age, geologists have to work with hand-drilling tools adapted to these special circumstances. A synopsis is given of these tools, and their use by the Geological Surrey.
Committee Du Neogene Mediterraneen1965Rutsch, R.F.44(3)
Metamorphic lineages of the orogenic plutonism1965Tex, E. den44(4)Firstly a tripartition of the orogenic plutonites based on their geological association and on the nature of their mafic minerals is proposed. Genesis of the micaceous and hornblendic granite-syenite-diorite-lamprophyre series through anatexis of water-saturated or slightly undersarurated rocks of suitable composition is discussed in the light of melting behaviour in the haplogranitic and wet basaltic systems. A similar derivation is argued for the orthopyroxenic charnockite-anorthosite-norite-pyroxenite series found to occupy deeper levels of the older orogenes especially. Here anatexis and palingenesis are presumed to operate in virtually water-free rocks in the granulite facies. The garnetiferous. Charnockite-eclogite-"alpine-type” peridolite series is believed to have suffered less anatexis and virtually no palingenesis. It is subdivided into a peripheral, low-temperature, ophiolitic suite of glaucophane-schist facies affiliation and a hight-temperature eclogite-facies suite situated in the very root zones of mainly precambrian and caledonian orogenic terrains. Secondly an artempt is made to trace the origin of the three series of orogenic plutonites through their alleged meramorphic lineages. A high-temperature, an intermediate, and a high-pressure lineage are discerned on the basis of so-called persister-minerals characteristic of the subfacies-series concerned. The high-temperature lineage leading towards the granitic series of plutonites is defined by the quasi-isochemical pairs: andalusite-sillimanite and biotite-cordierite. Its Iimiting geothermal gradients are discussed in the light of the stability field of "wet" Mg-Cordierite. The high-pressure lineage is shown to have many characteristic "persisters", but the low-pressure boundary curves of kyanite, zoisite + kyanite, pyrope, aragonite and jadeite + quartz are approached by geothermal gradients varying from 10 to 23°C/km and an average is struck at 18°C/km. This lineage is wide enough provide for at least two subfacies-suites ending up in the eclogite facies: a low-temperature plagioclase-free sequence from glaucophane-schist to eclogite and a higher temperature greenschist/prasinite/"alpine” amphibolite/garnet-clinopyroxene granulite suite characterized by the stable association of an epidote-group mineral and an increasingly sodic plagioclase. The intermediate lineage is less well-defined but it leads via the calcic plagioclase-orthopyroxene granulite subfacies to charnockitic, anorthositic, noritic, pyroxenitic, and related plutonites. Natural metamorphic series are not necessarrily confined to the artificial boundaries of the lineages here proposed, although the latter may aid in defining the former. Thirdly the probability in terms of density requirements is shown for having the "intermediate” zone of the orogenic crust, below the Conrad discontinuity, constituted by weighted assemblages of granulite and eclogite facies rocks instead of the usually postulated homogeneous basalt of gabbro layer. Also the water economy of the various regional metamorphic lineages is speculated upon against the background of a frequency analysis of water contents in regional metamorphic rocks grouped according to facies and silica-content.
Beschouwingen over het economisch meest gunstige ontginningssysteem in een kolenmijn in verband met de mijngasbestrijding1965Stuffken, J.44(4)The paper deals with a study undertaken to determine what combination of mining method and ventilation system will give the lowest costprice per ton of coal output under conditions where the production level of the longwall face is limited by the release of methane. In these considerations attention was given to the following three non-related factors. 1. the cost per ton of coal as a function of the rate of the daily advance of the face; 2. the volume of methane released per ton of coal produced; 3. the possibilities with regard to supplying the air volume needed and mixing the released gas. On the basis of these data a calculation programme has been developed which often permits of choosing the preferable system. The choice frequently turns out to be a combination of an advancing-and-retreating method with downcast ventilation.
Toekenning van de waterschoot van der gracht penning aan prof. dr. mr. F. Florschütz196544(4)
Jaarverslag 1964196544(4)
Aandrijvingen voor kolenschaafinstallaties1965Clercq, H. le44(5)
Directe aandrijving met draaistroommotoren voor kolenschaafinstallaties1965Zeegers, J.J.44(5)
Hydrostatische aandrijvingen bij ondergrondse pijlerinstallaties1965Stalman, M.E.44(5)
Aanbouwploeg met gelijkstroomaandrijving voor snelheidsregeling1965Omers, H.L.44(5)
International assocciation for the genesis of ore deposits1965Uytenbogaardt, W.; Tex, E. den44(5)
Geologie en bodemkunde1965Bennema, J.44(6)The differences between geology and pedology may be expressed as differences in depth scale and in rime scale. Pedology is studying only the uppermost part of the earth's crust, and is in the first place interested in recent and present changes induced by environmental forces in the geologic material. It is less than geology a historic science. There is, notwithstanding these differences, a strong relationship between geology and pedology, of which the following three aspects are considered: 1) Many soils are under the influence of the soil forming processes gradually developing into more mature or senile stages till the moment they are buried by sedimentation or destructed by erosion. Other soils are found in a steady state, the soil forming processes being in equilibrium with either sedimentation or erosion. The geologic phenomena of erosion and sedimentation are thus, to a great extent, governing the distribution of the soils of different stages of development 2) These different stages may, especially in the tropics, often be expressed as differences in weathering phases of the soil material. The knowledge of weathering is an important point of contact between geology and pedology. 3) Soils are mainly formed from geologic materials. Many characteristics of the soils are directly or indirectly related to the kind of geologic materials from which they are derived.
Fieldwork in the Charnockitic Precambrian of Rogaland (SW Norway)1965Tobi, A.C.44(6)In the "southern tip of Norway" a charnockitic type of Precambrian is found in two regions, a smaller one around Arendal in the east and a larger one in Rogaland in the west. In Rogaland, a complex of intrusive masses, chiefly consisting of anorthosites and of rocks varying from monzonites to norites, is surrounded by charnockitic migmatites. Outside of the Egersund Border Fault, which follows the boundary of the intrusive masses at some distance, the charnockitic migmatites are accompanied by garnet-rich migmatites perhaps comparable to the khondalites of peninsular India. The charnockitic character of the region is due to granulite facies conditions. Probably, we are dealing here with a sillimanite-cordierite subfacies. An interesting feature of this high-grade metamorphism is the blurring of the difference between magmatic and metamorphic phenomena. Another point for further study will be the gradual transition to rocks to amphibolite facies beIonging to the Telemark Precambrian in the east.
Symposium kool- en gasuitbarstingen gehouden te Nimes van 24 tot 28 november 19641965Maas, W.44(6)
Composition and origin of "Pedra Canga" and related ironstones in Northeastern Brazil1965Mabesoone, J.M.44(7)In tropical Brazil various types of ironstones occur. They have been sampled in the northeastern part of the country, observed in hand specimens and thin sections, and analyzed by X-ray, DTA, and chemically. From the data thus obtained two principal types of ironstones, occurring on top and in sedimentary rocks, could be distinguished. The first type, - conglomeratic ironstones crusts -, is of lateritic origin; however, the process of its formation remained unfinished. The other type, - iron-cemented conglomerates -, found in Cenozoic deposits, is a reworked and redeposited erosion product of the first type. The ironstone crusts occur in two levels. Their formation in closely related to the development of these levels. The crusts are fossil, and their age is presumed to be Middle Tertiary and Plio-Pleistocene, respectively.
De Krumbein-Tukey methode toegepast op de onderlinge vergelijking van Pleistocene zanden1965Crommelin, R.D.44(7)A. versatile method for analysing and testing various kinds of differences in rock bodies was published by W.C. Krumbein and J.W. Tukey in 1956 but did not receive due attention outside the United States. The present paper aims at reintroducing the method in a Netherlands journal by discussing and elaborating the general trend of thought and then applying it to a current sedimentary petrological problem. The method is based on a sampling design at various areal levels (multistage or nested sampling design) by means of which the overall variability in, for instance, the mineral composition of a region studied can be split up into separate components each of which is characteristic of one of the various levels distinguished (e.g. formations, exposures within formations, samples within exposures, etc.). The variability at a certain level is expressed as an interaction-effect between the unities at that level and the mineral species which constitute the analysis. The significance of these interaction-effects is subsequently tested by analysis of variance technique. The principle of the Krumbein-Tukey method is illustrated by two imaginary examples and some concepts related to the model are discussed. The arrangement of data and computations are shown in the Appendix. The method was next applied to the problem of differentiating between several sandy deposits in the Netherlands ranging from Old Pleistocene to Middle Pleistocene which for the rest are very similar. The sampling design was planned at three levels, viz. regions, exposures within regions and samples within exposures. The 150-105 micron fraction was examined for heavy minerals. The highest level was formed by the Emmen, Sibculo and Hattem regions representing different stratigraphical formations. The fourth region, Bergen op Zoom, was shown to be so different from each of the other three regions that it could be excluded from statistical testing. It could be shown that the difference between Sibculo and Hattem and also the difference between Sibculo and Emmen was very significant, whereas the difference between Emmen and Hattem was less distinct. Differences between the exposures in the three regions were always found to be very significant. Some evidence is given that under present conditions no reliable conclusions can be expected from correlation by means of mineralogical characteristics (correlation taken in the sense of determining stratigraphic position). The opinion expressed in a previous paper that the cover sands in the northern part of the Netherlands may be derived from the underlying proglacial deposits is supported by some results of this investigation.
On the tectonics of the Sierra de Carrascoy (Province of Murcia, Spain)1965Bodenhausen, J.W.A.; Simon, O.J.44(7)Recent reconnaissance in the Sierra de Carrascoy has revealed the presence of at least four major tectonic units. These units show strong resemblances with the four major tectonic units distinguished in the Sierra de Almagro - viz., from below to above, the Almagro, Ballabona-Cucharón, Variegato and Betic of Málaga units, - and also occur in the same tectonic order as in the last-mentioned mountain range. The presence of a counterpart of the Almago unit in the Sierra de Carrascoy in a similar position as in the Sierra de Almagro substantiates a recent view that this unit - which now has been found in various ranges a considerable distance apart - constitutes a separate structural element in the Betic Cordilleras.
A palynological study on the age of some borehole samples from the Amazonas Delta Area, NW Brazil1965Boer, N.P.; Hammen, T. van der; Wymstra, T.A.44(7)In the first part of this paper the results of a palynological investigation of borehole samples from the Amazonas Delta Area are discussed. The samples of one of the holes showed a typical Lower to Middle Cretaceous age; the samples from the two others had a Lower Tertiary to Upper Cretaceous flora. In the second part of this paper the tectonical and stratigraphical consequences of these results are discussed and a comparison is made between the Marajó and Guiana Basins.
International Mineralogical Association196544(7)
Winning en conditionering van het aardgas van Slochteren1965Bongaerts, J.M.P.44(8)After the discovery of Slochteren gasfield on 14th August, 1959 further appraisal, organisation, development and production succeeded and overlapped each other in a rather rapid succession. At this moment the field is already in production and producing ± 3,5 x 166 m3/day from one cluster. The system followed is rather simple. the permeability of the field and consequently the productivity of the wells allows withdrawal of gas in large quantities at only a few drainage points, called "clusters". At each cluster a unit is installed to treat the gas and condition it to pipeline specifications i.e. a water and hydrocarbon dewpoint of -2°C at pressures varying from 74 to 1 kg/cm2. This is necessary to prevent hydrate troubles and condensation of hydrocarbons in the pipeline system. The dehydration method followed is adiabatic expansion of the gas across a bean thereby using the Joule-Kelvin effect. This expansion results in a sharp temperature drop because of which water and heavier hydrocarbon condens and the gas gets a dewpoint of -12° C at 74 kg/cm2. This low temperature is required because of possible retrograde conditions. After this the gas is measured with the orifice method which uses as "a first" the gas density instead of static pressure, static temperature and compressibility in the flow computation. Also instead of multiple orifice meter system "one orifice meterrun" is used with a number of DP cells of a varying range. The whole plant and wells are highly automated and the complete operation is unattended, being run and watched from one central point. Numerous safety measures are incorporated one of which is the "bottom hole safety valve" in the well which again is a new development.
Een nieuwe methode voor de bevestiging van de schachtuitrusting aan de wand van een hoofdschacht1965Stuffken, J.; Amstel, J.A. van44(8)Fixing brackets to an existing concrete wall by means of anchor bolts provides a quick and simple method of mounting in place parts of a shaft installation, for instance the cage guides. This method saves much time in that it does away with the necessity of cutting holes in which beams have to be fixed with concrete. Neither is it necessary in the case of new shafts being planned to determine beforehand the places where recesses have to be made in the shaft wall, so that the choice of a particular type of shaft equipment can be postponed to a later stage.
Geological sketch of Svalbard Islands (Spitsbergen)1965Escher, E.F.44(8)A summary is given of the geology of the arctic archipelago of Svalbard, mainly on the base of publications. A geologically attractive feature of the Svalbard Islands, which cover in total about 64,400 km2, is the presence of a sedimentary sequence which belongs to the long time span from pre-Cambrian to Lower Tertiary inclusive; only few gaps exist. Probable pre-Cambrian basement, which is exposed in Northeast Land, is followed by the partly geosynclinal Hecla Hoek Group of formations, pre-Cambrian to Ordovician in age and up to 15,000 m thick. The lower part of the Hecla Hoek succession is metamorphosed. The sequence is strongly affected by the Caledonian orogeny and intruded by granites of which the youngest are Caledonian in age. Devonian sediments, which are developed in Old Red facies, are chiefly preserved in a downfaulted region in northern West Spitsbergen where their total thickness is estimated to be more than 5,000 m. They rest unconformably on Hecla Hoek and probably were eroded away in large areas in pre-Carboniferous time. From Carboniferous to Lower Tertiary Svalbard belonged to a shelf on which a predominantly marine sequence of clastic and, subordinate, carbonate rocks was laid down, interrupted by some intervals in freshwater or mixed facies. The principal region of exposure of post-Devonian sediments is central and southern west Spitsbergen. Formation thicknesses are variable; in the Isfjord region in West Spitsbergen approximate thicknesses are: Carboniferous-Permian 1,100-1,500 m; Mesozoic 1,300-2,000 m; Lower Tertiary 2,000 m. In Svalbard the dominant tectonic event is the Caledonian orogenetic phase already mentioned. There followed the Svalbard phase in Upper Devonian time, which mainly caused faulting. Variscan movements are proved on Bear Island, where Permian beds onlap unconformably on slightly folded older strata. Probably in Upper Cretaceous time West Spitsbergen and Northeast Land were tilted to the south. Alpine movements are assumed to have occurred in Upper Tertiary time. Their exact dating is not possible because of the absence of Upper Tertiary deposits. They resulted in the formation of a broad, flat syncline in southern West Spitsbergen and, along its western border, a zone of pronounced faulting and folding. Caledonian, Devonian and Tertiary structures and faults mostly are directed north-and-south to NNW-SSE; the younger structures obviously are influenced by the Caledonian direction, which generally is north-and-south. in Svalbard, between Upper Devonian and Lower Tertiary, coal seams were formed at various times. In recent years, in West Spitsbergen five mines exploited coal for export, one of them working Lower Carboniferous, the others Lower Tertiary seams.
Over de verspreiding van mammoetfossielen in noordelijk Nederland1965Boekschoten, G.J.44(8)Tentative explanations are given for the almost complete absence of mammoth fossils in the sediments of Saalian and Weichselian age of the Northern Netherlands. The northeastern provenance of the older fluviatile strata is thought to account for the absence of reworked skeletal elements. The Weichselian finds are restricted to the valley of the only larger river this could be due to ecological factors.
Exploration for oil and gas by emanometric methods1965Thomeer, J.H.M.A.44(9)Since the early twenties the occurrence was observed of hydrocarbon traces in the soil over oil and gas accumulations. These traces appear to form a halo pattern above the oil-water-boundary of the accumulation. Similar observations were made in respect to salt concentration and radioactivity. It would appear that these complex phenomena can be satisfactorily explained on the basis of rock load, subsequent fluid expulsion and capillary barrier effects. Whether, however, these halo's could satisfactorily be utilised for the explorarion and localisation of subsurface accumulations, seems rather doubtful. There are too many factors that rend to displace the halo or render its formation impossible. At best, emanometric surveys might supply supplementary information to orthodox geological and geophysical observations, and even this under locally favourable conditions only.
Paleomagnetic investigation in the Vänern district (Sweden)1965Mulder, F.G.44(9)Orientated samples of dolerite and limestone were collected in Sweden for a paleomagnetic investigation. The limestone samples are of Ordovician age and the dolerite samples are from two sills intruded in Silurian shales. At demagnetization with the use of A.C. fields up to 900 Oe, the limestone samples show only a little decrement of magnetization. Therefore, only the magnetization of the non 'cleaned' samples is given, The average magnetic direction of the limestone samples is: decl. 198°; incl. -4°; with a cone of confidence α95=11° and a pole position of 31° N; 173° E. All the dolerite samples, also demagnetised with the use of A.C. fields up to 900 Oe, show a total loss of magnetism. Samples from the sill NW of Skövde (Billingen) gave the following results: decl. 198°; incl. -2°; with a cone of confidence α95=3° and a pole position of 31° N; 172° E. Samples from the sill E of Trollhättan (Hunneberg) gave the following results: decl. 203°; incl. with a cone of confidence α95=3° and a pole position of 38° N; 162° E.
De ontwikkeling van een slagwalsbreker1965Minkhorst, J.H.K.; Muysken, P.J.44(9)The raw coal from a long-wall face often contains large lumps of coal and stone, which may cause spilling and stoppages in the outbye conveyorbelts and transfer points. "Beien" coal crushers, comprising a single slow-speed toothed roll mounted in a swinging frame on the stageloader, have been used for many years. Dutch State Mines have developed an impact roll for the same of a similar frame. It consists of a heavy roil with one breaking ridge, which is excentrically suspended by compound leaf springs between two circular disks carried on the horizontal shaft driven at a speed of 240 r.p.m. Mass and speed give the roll sufficient kinetic energy to break hard material without slowing down. Fitted with this impact roll the crusher has satisfactorily handled large lumps of hard stone, which used to pass unbroken. Due to low cost this small unit may also compete against hand sledging of large lumps in a small crushing plant.
Tectonics of the late Precambrian ignimbrites in western Rajasthan (India)1965Rutten, M.G.44(9)The Late Precambrian Malani Rhyolites of western Rajasthan, India, are formed predominantly by ignimbrites. Several of the isolated outcrops of the Malani Rhyolites show extremely strong westward tilting. This is thought to be an effect accompanying transcurrent faulting inherent upon the northward drift of the Indian subcontinent.
Mega-undations as cause of continental drift1965Bemmelen, R.W. van44(9)After a short review of newer acquisitions of our geonomic knowledge, a mechanical model is conceived for the explanation of mega- and geotectonic processes. The motor, providing the gravitational energy, is sought in the lower mantle (turbulent or laminar flowcircuits in material with a Newtonian viscosity). The outer spheres (upper mantle and crust) are elevated and depressed by these deep-seated flowsystems, forming extensive deformations of the geoid, measuring thousands of kilometers across, called megaundations. The upwarps spread under gravity and the downwarps contract by means of a composite gravity flow of matter which is largely in a crystalline state. This flow is characterized by (hot-) creep deformations (Andradean viscosity), and it is accompanied by continental drift.
Coccoliths and discoasters1965Cohen, C.L.D.44(10)A short review is given of the principal biological characteristics of the little known group of the Coccolithophorids. The related Discoasters are shortly mentioned. Some of the technical details are described that are to be used when working with these very small forms. Their rôle as rockbuilders is briefly mentioned and some aspects are described of their use in stratigraphic paleontology. A few examples are given of their application in biostratigraphic zonation and correlation. Their advantages and disadvantages are shortly reviewed
Een vondst van marien icenien in de achterhoek1965Rees Vellinga, E. van; Ridder, N.A. de44(10)
An approximation to the genetic classification of non-organic sedimentary structures1965Nagtegaal, P.J.C.44(10)Non-organic sedimentary strucures are divided into three major groups according to the time and site of their formation. The three groups are: 1) syndepositional structures, 2) metadepositional structures and 3) postdepositional structures. The moment of final deposition of a sedimentary grain is taken as time reference and the depositional interface is used as spatial reference. On the basis of this threefold division a classification is developed which, to a limited degree, makes it possible to group together genetically related structures.
Isotopic ages of two granites on the Iberian continental margin: the Traba granite (Spain) and the Berlenga Granite (Portugal)1965Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H.44(10)
De gravimetrische stofgrenzen van het stofinstituut1965Malta, W.P.M.; Terpstra, J.44(10)The dust concentration limits I/II, Il/III and III/IV of the "stofinstituut van de Gezamenlijke Steenkolenmijnen in Limburg" approximately can be described by the hyperbolic function G=x/A+11 mg/m3, in which: G= dust concentration in mg/m3; A = ash content of the dust in % and x = respectively 1170,1750 and 2620. This holds for ash percentages between 10 and 100 %. The dust concentration limits of dust with ash percentages between 0 and 10 % ate equal to those of dust with 10 % ash. Die Staubgrenzwerte Staubstuten l/II, II/III und III/IV des "stofinstituut van de Gezamenlijke Steenkolenmijnen in Limburg" werden annähernd durch die hyperbolische Funktion G=x/A+11 mg/m3 dargestellt; hierin ist G= die Staubkonzentration in mg/m3 A = Aschegehalt des Staubes in % und x= bezw. 1170, 1750 und 2620. Diese hyperbolischen Funktionen sind annähernd gültig für Aschegehälte zwischen 10 und 100%. Die Staubgrenzwerte von Stäuben mit Aschegehälten zwischen 0 und 10 % sind deren mit einem Aschegehalt von 10 % gleich.
On the estimation of relative grain frequencies in heavy mineral slides1965Harten, D. van44(10)Counting methods, applied in order to obtain information on grain frequency in heavy mineral residues are critically reviewed. The method of line counting is discussed in some detail from a theoretical point of view, the conclusion being that this method should not be used as a means of obtaining relative grain frequencies in instances where mineralogical character and grain size are correlated. The technique of ribbon sampling, being insensitive to particle size, is proposed instead. Line and ribbon counting methods are tested in some artificial two-component slides of known composition. Finally, the results of comparative counts in slides prepared from a natural sediment are discussed.
In memoriam prof. dr. mr. F. Florschütz1965Hammen, T. van der44(10)
Hercynian and alpine orogenies in Northern Spain1965Ulbo de Sitter, L.44(11)In northern Spain many different orogenes have developed since the Pre-Cambrian and lasting into the Alpine period. In the western part a N-S strike predominates, in the central and eastern part an E-W trend. The intensity of both the Hercynian and the Alpine E-W striking tectonic deformation, increases eastwards. The Pyrenees are separated from the Cantabrian Mts and the Celtiberic chain by the Ebro block. Both the basin development and the tectonic deformation is largely dependent on fundamental faults and ridges of which the North-Pyrenean fault and the León line are the most important ones. Cross folding and divergent fold trends are partly due to successive N-S and E-W stress fields, partly to the block boundaries formed by these fault lines and their splays.
The age of the Mondoñedo formation and the mastodon fauna of Mosquera (Sabana de Bogotá)1965Hammen, T. van der44(11)The Mondoñedo Formation is found at the edges of the Sabana de Bogotá (Colombia), that was formerly a pluvial lake. The formation, known for its fossil Mastodon.fauna, is here provisionally subdivided into Upper, Middle and Lower Mondoñedo Formation, The Upper Mondoñedo Formation consists of an upper recent soil, a series of sandy loams often with angular gravel, and a lower soil-complex. This soil-complex contains charcoal which was C14-dated on two places, as resp.10,760 ± 160 and 10,840 ± 110 yrs. The charcoal from the Alleröd soil-layer of Europe has the same age. It corresponds there to the time that certain tree-species died as a result of the deterioration of the climate at the very end of the Alleröd-Interstadial, becoming an easy prey for natural forest-fires. Near the base of this soil-complex, or just below it, angular gravel is present together with fragments of "Limonitic Crust" (derived from erosion of the Lower Mondoñedo Formation). The Middle Mondoñedo Formation consists apparently mainly of the sandy "Brown Loams" and equivalents, and at its base (just on top of the "Limonitic Crust") the Mastodon-fauna is found. A molar of Mastodon was analysed for its fluorinecontent by C. J. Overweel. The percentage (0.90 %), suggests an approximate age of Early Würm-Glacial to Late Riss-Würm-Interglacial. The Lower Mondoñedo Formation consists of the "Red Loams" and equivalents, covered locally at the top by a "Limonitic Crust". This part of the formation may eventually be as old as, or perhaps even older than Riss-Würm-Interglacial
De kolenproductie en energievoorziening van West-Europa1965Muysken, P.J.44(11)
Chamosite in recent sediments of the Niger and Orinoco deltas1965Porrenga, D.H.44(11)The mineralised faecal pellets in Recent shallowwater sediments of the Niger and Orinoco deltas contain mainly authigenic poorly ordered chamosite with a fairly high magnesium content. Photographs, chemical- and X-ray data of these chamositic pellets are given and their origin and occurrence are discussed.
A dip comparator for routine geological investigations of aerial photographs1965Rondeel, H.E.44(11)
Tilt-compensating compass1965Bouma, A.H.; Mutti, E.; Maarschalkerweerd, M.H.44(11)A light weight tilt-compensating compass has been constructed, It enables the investigation to measure the pretectonic directions of linear sedimentary structures of a folded series. The compass can also be used to mark the orientation of samples before they will be collected.
Hot ontwerp van de nieuwe losvloer van staatsmijn Emma1965Clercq, H. le44(12)The top landing mine car circuits at four "Staatsmiinen" collieries were replaced or reconstructed in the period 1955-1965. The last renovation, that of the hang bench circuit at the "Emma" colliery was finished in 1965.Its design is the most advanced as it was based on the experiences gained in the previous reconstructions. Operations on the "Emma" landing stage, serving a four cage shaft with a capacity of 340 mine cars of 2500 litres or 1000 tons gross per hour, are full automatic and supervised by two bankmen only. The track scheme was kept as simple as possible; for reversing the cars turn-tables are used. There are two tipplers, each for three products and no provision was made for a stand-by tippler. Full automation was obtained by regarding the car circuit as a whole from the functial point of view. Descriptions are given of the principle of automation as well as of some examples,
Zyklischer bewegungsablauf beim vorrücken orogener fronten und der mechanismus des Deckschollentransports nach dem surf riding-prinzip1965Wunderlich, H.G.44(12)A characteristic of advancing orogenic fronts is a phase shift in successive movements, which expresses itself in a retardation of the movement maxima and a lateral shift in the zones of strongest movement with respect to the region in which activity takes place at present. In this connection, it is possible to consider the movements at the orogenic fronts as cycles that bear a formal resemblance to the propagation of an impulse in the form of waves. Vertical and horizontal crustal movements are interrelated like the orbital movements of point masses. The horizontal and vertical movements as well as the sum of the elevation and depression and the sum of the compression and stretching of the crust during the passage of the front can be described by curves of trigonometrical functions. The maxima and minima of these curves form clues as to the location of gravitational anomalies in the orogen, the region of most severe crustal shortening or stretching, local steepening of the temperature gradient and the paths ascending plutonics and volcanics are most likely to take. Comparing the undulatory propagation of the zone of maximum horizontal movement towards the foredeep with the motion of water waves provides a simple explanation of the long-distance transport of tabular crustal fragments: they are carried forward like surf broads. This assumption makes superfluous both the expulsion of such crustal fragments from distant steeply dipping root zones and the long slopes required by gravitational sliding. Kennzeichen vorrückender Orogenfronten ist die Phasenverschiebung der Bewegungsvorgänge, die sich in einer Verzögerung der Bewegungsmaxima und einer seitlichen Verschiebung der Zonen stärkster Effektivbewegungen gegenüber den Bereichen gegenwärtiger Aktivität äussert. Die Bewegungsvorgänge an orogenen Fronten lassen sich dabei deskriptiv als zyklische Abläufe auffassen, die eine formelle Ähnlichkeit mit der Fortpflanzung des Impulses bei Wellenbewegungen besitzen. Horizontal- und Vertikalbewegungen der Kruste greifen dabei im Sinne einer Orbitalbewegung der Massenpunkte ineinander. Als beschreibende Funktion für diesen Bewegungsablauf ergeben sich Kurven von 'Winkelfunktionen, und zwar für Horizontal- und Vertikalbewegungen sowie für die Summe der Hebung bzw. Senkung und der Einengung bzw. Dehnung der Kruste im Laufe des Frontdurchganges. Die Maxima und Minima dieser Kurven ergeben Anhaltspunkte für die Iage der Schwereanomalien im Orogen, für Bereiche stärkster Einengung oder Krustendehnung, örtliche Versteilung des Temperaturgradienten sowie für günstige Aufstiegswege der Plutonite und Vulkanite. Aus der wellenartigen Fortpflanzung des Bereiches maximaler Horizontalbewegung in Richtung zur Vortiefe ergibt sich in Parallele zum Bewegungsablauf von Wasserwellen eine einfache Erklärung für weitreichenden Horizontaltransport flacher Deckschollen ähnlich dem Vorgang beim Wellenreiten (surf-riding), welche die Annahme sowohl einer Auspressung dieser Deckschollen aus ferngelegener, steiler Wurzelzone als auch der für gravitative Freigleitung erforderlichen entsprechend langen Böschungsreege überflüssig macht.
De relatie tussen katteklei, pyriet en gips in de Luxemburgse Trias1965Sijperda, W.S.44(12)During a field-trip the yellow parts in variegated clay lenticles in a triassic pebble deposit near Reichlingen, Luxemburg, were recognised as cat's clay, a basic ferric sulphate, comparable to the car's clay occurrences in certain holocene soils in The Netherlands. Cat's clay originates by oxidation of pyrite in the absence of calcium carbonate. If calcium carbonate is present gypsum is formed. At Reichlingen the pyrite left cubic holes after oxidation. The pebble deposit is likely to belong to the same time - stratigraphic unit as the variegated marls near Diekirch. These marls contain bands of gypsum and cubic pseudomorphs, known as halite pseudomorphs. It is argued that the pseudomorphs at Diekirch and the cubic holes at Reichlingen are similar: in both cases pyrite cubes were oxidized. This oxidation gave rise to the development of cat's clay in the near-shore facies (no presence of calcium carbonate), and to the formation of gypsum in the "normal" facies where calcium carbonate was present. The cubic pseudomorphs in the triassic marls, therefore, are not halite pseudomorphs but pyrite pseudomorphs. The gypsum did not originate by primary sedimentation but by weathering of pyrite.
Der meteorit von Kangean (Indonesien) (Ein olivin-bronzit-chondrit)1966Niggli, E.45(1)The Meteorite of Kangean (an island of Indonesia, NE of Java) felI on September 27th, 1908; it is described here for the first time. The original weight is not known, as the meteorite was broken up by the people who found it. A mass of 1632.973 g could be recovered, certainly more than half the original stone. This meteorite is deposited in the Mineralogical-geological Museum in Delft (Technical Institute), Netherlands. The surface of the meteorite is covered with a black fusion crust; the front face of the lenticular body shows well developed piezoglypts. The structure is chondritic. The meteorite is rather strongly weathered. The mineralogical composition is: olivine (Fo80-82), bronzite (~ En82), nickel-iron, troilite, chromite, ? plagioclase, glass and secondary iron hydroxydes. The meteorite is an olivine-bronzite-chondritre. The nickel-iron bodies of the meteorite were investigated with the electron microprobe. Profile analyses were made for Fe, Ni and Co. Most of the bodies (type A) consist mainly of kamacite with few inclusions of taenite grains; we found also however bodies (type B) of which the main mass is taenite with regularly distributed small inclusions of kamacite. In the taenite grains in bodies of type A the Ni-content is higher at the borders than in the middle parts of the grains. The distribution of the cobalt in the nickel iron bodies coincides roughly with that of iron and not with that of nickel.
Probleemstelling bij het ontwerp van de nieuwe losvloer van staatsmijn Emma1966Antkowiak, W.A.45(1)The forty years old pithead of Emma Colliery, Dutch State Mines, was designed for one type of coal only. Gradually, more types of coal had to be handled, involving a number of complications that acted as a check on the pithead capacity and stood in the way of technical developments, such as automation. Consequently technical adaptation of the excisting pithead was not a sufficient answer to the problems associated with the introduction of larger mine cars, but demanded a more fundamental approach.
Isotopic age determinations on Surinam rocks1966Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H.45(1)
#REF!1966Thiadens, A.A.; Plas, L. van der; Snell, A.W.45(1)
Depositional environment and provenance of the sediments in the Guadalete Estuary (Spain)1966Mabesoone, J.M.45(2)The river Guadalete in SW. Spain has excavated a 8-10 m deep estuary of which. two thirds have been filled up with almost clayey deposits mainly in postroman times. Many samples were taken with a hand auger. The amount of material thus obtained was only small. This made some special investigation techniques necessary. The grain size of the thin sand layers was determined by a counting method in which at the same time roundness is measured. It appears that the centre of the northern estuary part was filled up by the Guadalete, whereas the lateral parts are derived from recent and subrecent beaches. The southern estuary part, however, got its few sand layers chiefly from reworked older marine deposits exposed in the valley slopes. By means of geochemical methods, furthermore the environment has been reconstructed in which the clay was deposited. The ratio calculated from exchangeable K, Na, Ca, and Mg indicates that this environment has always been marine to brackish. Only the uppermost clays at the beginning of the northern marsh part show some fresh water influence. Boron and lithium, which occur in a greater quantity in marine clays than in fresh-water clays, confirm these results.
The Susaća-interstadial and the subdivision of the late-glacial1966Hammen, T. van der; Vogel, J.C.45(2)During a recent pollen analytical study of a Holocene and Late-Glacial section from Cienaga del Visitador (Susaća, Eastern Cordillera of Colombia; van der Hammen & Gonzalez, 1961), an "interstadial" was recognized, earlier than Allerød and Bølling s.s.. A C 14 date showed that this interstadial must be somewhat older than 12,770 + 130 B.P. (GRN 3053), a clate for the cold phase between Bølling and the above mentioned ínterstadial. This fact led us to reinvestigate a number of dated pollen diagrams from different parts of the world. Several facts seemed to confirm the existence of a pre-Bølling Late-Glacial interstadial, and we therefore think it justified to introduce a name for it: the Susaća -Interstadial. It lasted from about 13,700 to 13,100 B.P. The pertinent data from various parts of the world relevant to the dating of the interstadial are presented, as well as a more complete subdivision of Late-Glacial time resulting from this work.
Isotopic evidence for Upper-Cambrian or Lower-Ordovician granite emplacement in the Vigo area, North-Western Spain1966Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H.; Floor, P.45(2)
Structural observations in the bude to tintagel area of the coast of North Cornwall, England1966Freshney, E.C.; McKeown, M.C.; Williams, M.; Dearman, W.R.45(2)
Tectonics of the North Cornish coast England1966Mackintosh, D.M.45(2)
Structural observations in the bude to tintagel area of the coast of North Cornwall, England and Tectonics of the North Cornish coast, England, a reply1966Zwart, H.J.45(2)
Sedimentatie in de zuidelijke bocht van de Noordzee - Tektonische consequenties van het paleomagnetische onderzoek aan de permische porfieren van Lugano, Noord-Italië1966Houbolt, J.J.H.C.; Hilten, D. van; Zijderveld, J.D.A.45(2)
#REF!1966Plas, L. van der45(2)
Reversal of air flow by a fire 1966Maas, W.; Sadée, C.45(3)The calculations given in this paper show that the temperature of the gases in the return airways behind a fire greatly influences the chance of a reversal of the ventilating air in parallel districts. A method to predict these temperatures behind a fire is given. The temperature in the fire has to be known. Calculations give this temperature for a fully developed timber fire. Some general conclusions which are important for fire-fighting are drawn.
Rotated magnetite crystals from the Rocroi massif (Ardennes)1966Zwart, H.J.; Oele, J.A.45(3)The rotation about the B-axis of magnetite crystals in Cambrian phyilites from the Rocroi massif is described. A possible explanation for this rotation in connection with the folds is given.
De mijnwetgeving op de Noordzee1966Driessen, C.F.45(3)
Cosmos and the Evolution of Life196645(3)
Rationalisatie in het ondergronds bedrijf van een kolenmijn - organisatie en techniek1966Kraak, J.45(4)
The pliocene and quarternary of the Sabana de Bogotá (the Tilatá- and Sabana formations)1966Hammen, T. van der45(4)The age and the correlation of the Pliocene and Quaternary formations of the Sabana de Bogotá (Colombia) are discussed. New data of pollen analysis, C14 dating etc. lead to the differentiation of two postfolding formations: one of Pliocene age, containing a tropical pollen flora, and one representing the Quaternary, containing an upland pollen flora. It is argued that the first one probably corresponds to the type Tilatá Formation, and the second one to the Sabana Formation as basically proposed by Hubach. An attempt was made to date the morphological units distinguished by JuIivert (1961) in the Southern Sabana de Bogotá. His "high-terrace" of the Tunjuelo Valley was cut into Würm-Glacial sediments. The "cone" of the Tunjuelo Valley is most probably a fluviogiacial deposit of Riss-Glacial time. The altered, often kaolinitic, marginal sediments, found above the proper level of the flat part of the Sabana, correspond only partly to the "high-terrace". They are eroded sediments of different (Quaternary) ages, deposited when the lake-level was high, and eroded when it was low, a cyclic phenomenon that reccured at least 12 times.
Uitreiking van de Waterschoot van der Gracht penning aan Ir. A. Hellemans196645(4)
Note préliminaire sur l'âge des roches de l' "unité cucharón" dans la Sierra de Carrascoy (Province de Murcie, Espagne)1966Simon, O.J.45(4)
Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap - Jaarverslag 1965196645(4)
The Siljan ring of Paleozoic, Central Sweden: A posthumous ringcomplex of a late Precambrian Dala porphyries caldera1966Rutten, M.G.45(5)The Dala Porphyries, recently mapped by Hjelmquist, from a volcanic province of late Precambrian age in central Sweden, attaining a minimum volume of volcanics of 150 km3. The Siljan ring of eaily paleozoics, distinguished from the early Paleozoic epicontinental cover of the Fennoskandian Shield by its thicker facies, with reef limestones, and by its peculiar, strong tectonization, occupies a ring 45 km in diameter and 5 km to 10 km wide, to the east of the Dala Porphyries. It is postulated that the Siljan ring structure developed as a result of posthumous movements at the site of the ring-complex surrounding a caldera from which the Dala Porphyries had erupted earlier.
Versterking van een gietijzeren schachtbekleding door middel van een deformeerbare manchet1966Bruens, F.P.; Moonen, J.G.D.; Weehuizen, J.M.45(5)
De invloed van de inclinatiefout bij paleomagnetische waarnemingen op continentverschuivingen en aardexpansie1966Hilten, D. van45(5)
Fouten in palaeomagnetische poolposities ten gevolge van systematische fouten in de palaeomagnetische inclinatie1966Hospers, J.45(5)
Lower Cretaceous planktonic foraminifera from the subbetic of Southern Spain1966Hermes, J.J.45(5)A fauna of planktonic Foraminifera from the Subbetic near Caravaca contains GIobigerineIIoides bIowi (Bolli), Globigerina graysonensis Tappan and some other species, probably including Hedbergella infracretacea (Glaessner). This association is believed to indicate an early Aptian, possibly a late Barremian, age. The succession of planktonic foraminiferal faunas of the early Cretaceous is discussed and shown to be far from settled.
Internationaal congres van directeuren van mijnbouwkundige veiligheidsinstituten - Sheffield 19651966Maas, W.; Sadée, C.45(6)
Aspects techniques et economiques de l'energie geothermique1966Dam, A. ten45(6)This paper gives a very general summary of the presently known distribution of geothermal fields; geology and mechanism of such fields, exploration methods and technical means are discussed. In the last chapter the economic aspects of geothermal energy are discussed. Geothermal exploration has much in common with petroleum prospection and should interest any country where on geological grounds this new form of energy could be present. Taking into account the risk factor involved in any exploratory operation, electricity can be generated with natural steam at lower cost than with other sources of energy.
Isotopic age determinations on tourmaline granite-gneisses and a metagranite in the eastern Betic Cordilleras (South-Eastern Sierra de Los Filabres), S.E. Spain1966Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verschure, R.H.45(6)
isotopic age of the Quartz-diorite batholith on the island of Aruba, Netherlands Antilles1966Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H.; Lagaay, R.A.45(6)
Isotopic age of tin granites in Rondônia, N.W. Brazil1966Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verschure, R.H.; Bon, E.H.45(6)
Tectonics of Late Precambrian ignimbrites in western Rajasthan (india) - Discussion1966Mukherjee, A.45(6)
Considérations sur la composition, la genèse et la classification de la Tourbe, du lignite et de la houille1966Kreulen, D.J.W.45(7)Considerations on the composition, the origin and the classification of peat, lignite and coal. In this paper it is attempted to bring under one common denomenator certain specialized, professional views on the composition and genesis of peat. lignite and hard coal. The chemical part starts with the conception rank and ends with information about aromaticy, ringcondensation index and molecular size of the mean structural unit. The H/C versus O/C diagram (fig. 3) is noticed. Thereupon the conditions which control the formation of peat, lignite and hard coal are discussed. The objections made by W. Gothan and R. KräuseI against the swamp theory of H. Potonié are mentioned and appreciated. The transformation of plant débris is conceived as the result of biochemical transformation together with oxidation and reduction phenomenae. It is stressed that humic acids ate often improperly considered as intermediate stage during coalification. Their structure points clearly to a formation by oxidation. Consequently it is supposed that the transformation of plant débris resulted in lignite or hard coal respectively accordingly to predominance of oxidation or reduction reactions. This idea is on the root of a new classification scheme (fig. 6) in which all immature coals have an appropriate place. The author fails to see pressure as a controlling factor of rank. Experiments are mentioned (fig. 4, A and B) in which the appearance of an earthy brown coal (brown and dull) changed to black and glossy under a pressure which was equivalent to that of a normal, average, overburden. During this treatment the ultimate analysis, however, did not change. Other experiments are mentioned which demonstrate an increase in carbon content of cellulose and lignine when exposed to relatively low temperatures (130 °C) for long periods of time (up to 3200 h). It was established that the transformation under these conditions is accelerated by water. Finally reference is made to a booklet in the german language in which the subject is treated more amply.
Palaeomagnetism of some central European mineral deposits and its geophysical significance1966Krs, M.45(7)Palaeomagnetic research conducted on several types of Central European mineral deposits (pneumatolytic, cata - to epithermal), distributed throughout metallogenic regions of various tectonic development, has fully bore out the view that under certain conditions palaeomagnetism can be used for dating epigenetic mineralization. New palaeomagnetic data, supplemented by an extensive laboratory study of palaeomagnetic stability, provide new interpretation aspects for palaeomagnetism concerning the reconstruction of tectonic development, and thermal history of mineral deposits, as compared with earlier results (V. Flanus and M. Krs, 1963a). The polar windering path derived from the palaeomagnetism of products of various mineralization processes coincides remarkably with the polar wandering path for the Eurasian continent as derived from the palaeomagnetism of biostratigraphically dated rocks (ranging from the Carboniferous to the Quaternary). A discussion is presented concerning the possibility of tentatively determining the intensity of the geomagnetic field in the geologic past, based on investigating thermoremanent magnetization of cassiterite (SnO2) with Fe-ions attached to its lattice. A study of the "thermal memory" of cassiterite yielded data strongly contradicting the regeneration of cassiterite deposits in the past. A similar conclusion was reached previously (M. Krs, 1964b) for hydrothermal deposits where haematite acts as carrier of palaeomagnetism.
Using quantitative methods in geology1966Kauffman, M.E.45(7)
Contribution of the bureau of mines to the geology of the central mountains of West New Guinea1966Wegen, G. van der45(8)In 1960 the Bureau of Mines in former Netherlands New Guinea took up the investigations in those areas of the southern part of the territory, where-a-private enterprise explored for alluvial gold deposits before the Second World War. The gold finds were not of largescale mining importance. The investigations, renewed by the Bureau of Mines, intended to trace the possibility of exploitation on minor scale. The problem of the origin of the alluvial gold is of academic importance, since the investigations of 1960 and 1961 led to negative results. The area in question must be sought on the south flank of the crestal part of the Central Mountains. The Bureau of Mines commenced the survey of the geologically most unknown region of the Central Mountains in 1961. The survey was restricted to several reconnaissances and ended with the transfer of the administration of West New Guinea to the United Nations Temporary Executive Authority on the first of October,1962.
Antidune bedding in the Namurian of Derbyshire, England1966Collinson, J.D.45(8)Massive beds from a channel fill sequence in the Namurian of Derbyshire are described. From a comparison with modern, flume-produced, structures and from a hydrodynamic interpretation of the sequence of sedimentary structures, it is concluded that the massive beds were deposited in the upper part of the upper flow regime and therefore represent the first recognised antidune deposits in ancient sediments.
A continuous reflection profile along the Netherlands coast from Walcheren to Den Helder1966Collette, B.J.; Lagaay, R.A.45(8)A reflection profile along the Netherlands coast from Walcheren to Den Helder is presented, obtained with the so-called air gun profiler. The penetration was one second. The downdipping of the layers from the Brabant massif, the extension of the Saxonic 'anticlinal' zone Rotterdam- The Hague, and the thickening of the sediments towards the North are recognized. The base Quaternary and the base Tertiary are tentatively identified.
Note on the formation of stylolites1966Manten, A.A.45(8)Described here are a number of observations on stylolites, found in Silurian limestones in the island of Gotland (Sweden). The three current theories on stylolite formation are briefly summarized. Only the solution-pressure theory of Stockdale can satisfactorily explain the origin of the stylolites in Gotland.
Mineral analysis by means of thin layer chromatography using liquid iion exchangers1966Vries, G. de; Sijperda, W.S.45(8)A rapid chromatographic technique using a thin layer of silica gel impregnated with liquid anion exchangers on small glass plates is introduced in mineral analysis. The principles of the ion exchange process and the practical application are outlined.
In memoriam - Professor Dr. Ir. Felix Andries Vening Meinesz1966Colette, B.J.45(9)
Glaucophanitic stone implements from West New guinea (West Irian)1966Verhofstad, J.45(9)A collection of hand polished stone adzes and other stone implements in use by native tribes in the Central Highlands of West New Guinea (West Irian) is described. All the specimens are glaucophanites containing epidote, glaucophane and lawsonite as principal minerals. Glaucophane-bearing rocks have not been described earlier from New Guinea. No field data are available but there is evidence that the rocks come from a zone of low-grade metamorphic and basic to ultrabasic igneous rocks existing along the northern edge of the Central Ranges. The blue to green rocks are very fine grained and many show a fine undulating banding. Mineralogical aspects include the occurrence of several members of the glaucophane-riebeckite series, of lawsonite in subradiating “sheaves” and of colourless pumpellyite; the last mineral however was not identified with certainty. It is concluded that these glaucophanitic rocks from New Guinea belong to the lawsonite-pumpellyite-epidote-glaucophane sub-facies as defined by Miyashiro and Seki (1958) from Japanese metamorphic terrains.
On the occurrence of oolitic limestones, intercalated in pelagic Aptian-Albian marls in the subbetic WNW of lorca (Prov. Murcia - Spain)1966Dekker, L.; Rooijen, P. van; Soediono, H.45(9)Evidence has been found that layers of oolitic limestones and other calcarenites, intercalated in Aptian-Albian marls rich in Radiolaria and planktonic Foraminifera, consist largely of redeposited ooliths and rock fragments carried into the marl basin by gravitational transport. This proves the existence, during Aptian-Albian times, of an eroded area, probably within the Subbetic paleogeographic realm. As shown by the age of redeposited material in the oolites, the hiatus involved covers a sequence from Upper Dogger or Lower Malm to Aptian-Albian age
Diaklaasvorming in de diepte (t.g.v. de lithologische druk), als oorzaak van open trekscheuren in de hogere gesteentelagen1966Gramberg, J.45(9)
Mineral analysis by means of thin layer chromatography using liquid ion-exchangers. Part III Data on non-sulphidic minerals. Part II: Qualitative analysis of sulphide ore minerals1966Sijperda, W.S.; Vries, G. de45(9)Thirty sulphide minerals have been analysed using the rapid thin layer technique described in part I. After preparation of the test solution chromatograms were run using 2, 6 and 10 N HCI as eluants. Then the constituents were visualized with the aid of suitable reagents. Combination of Rf value and mode of detection reveals the identity of the constituents. The results are discussed.
Chemical procedures for the praparation of rubidium and strontium samples for isotopic age determination1966Boelrijk, N.A.I.M.45(9)
Het aardgastransportnet in Nederland1966Walkate, H.J.45(10)
Scour-and-fill structures from a fluvial piedmond environment1966Nagtegaal, P.J.C.45(10)Conglomerate-filled scour-and-fill structures are of frequent occurrence in Eo-Oligocene fluvial piedmont deposits in the Southern Pyrenees (Spain). Many scour-and-fills occur at the erosive bases of conglomeratic sheetflood deposits which alternate with sandy siltstones; others are found both within the conglomerates and isolated in the sandy siltstones. The latter type develops out of the downstream terminations of the conglomerate sheets. Of 376 scour-and-fills eroded into sandy silt, 35% shows load deformation. The most frequently deformed structures are those having an estimated initial width/depth ratio of about 2. diagrams show that the scour-and-fills, which were locally found to occur in a braided pattern, are very nearly parallel to each other in restricted areas. The general orientation pattern is related to an underlying unconformity surface carrying a pronounced relief. The width/depth ratio of the scour-and-fills eroded into sandy silt tends to increase in the downstream direction. In the Pobla de Segur area the downstream increase of the width/depth ratio is accompanied by a decrease of the cross-sectional area of the scour-and-fills.
Prallhammermessungen im steinkohlenbergwerk Emma-Hendrik der Staatsmijnen in Limburg1966Beuken, H.; Absil, P.45(10)Until recently, the crushing strength of rock adjacent to coal seams was measured by means of hydraulic jacks. The crushing strength of coal could not be determined underground owing to the required vertical positioning of the jack. The use of the "Betonprüfgerät Type N" (Testhammer) was known from German mining practice. This hammer has now been tested at Emma-Hendrik colliery. It was found to be a simple and handy appliance for measuring the crushing strength of rock and coal in situ. Its low weight and small dimensions, added to the circumstance that the measurements can be performed both easily and at low cost, have contributed towards making the "Testhammer" a widely used tool in mining practice. The crushing strength figures obtained with the Testhammer have proved to be very reliable.
interrelation of metamorphism and deformation in Central Singhbhum, Eastern India1966Baran Roy, A.45(11)The metamorphic rocks in central Singhbhum show two periods of metamorphism, the earlier progressive regional metamorphism having been followed by retrogressive metamorphism in zones of shearing. The isograds of the progressive regional metamorphism are roughly parallel to the trends of the sub-horizontal fold axes and the index minerals formed during this metamorphism form a progressive series in time. The metamorphism is broadly coeval with the folding movements and predates the shearing movements which initiated the retrogressive metamorphism. No cause-and-effect relationship exists between the regional metamorphism and the granites of the region.
Biostratigraphy of Upper Jurassic and Cretaceous sediments near Caravaca (SE Spain) with special emphasis on Tintinnina and Nannoconus1966Geel, T.45(11)The Nannoconus zones recognized by Brönnimann in Cuba and by Baldi Beke in Hungary and the Tintinnina zones found by Remane near Grenoble are reported from a section near Caravaca in southern Spain. In the same section planktonic Foraminifera and ammonites occur. The correlation and the age of the various biozones is discussed.
Report on the discovery of a rudist in Upper Cretaceous pelagic limestones near La Parroquia (Prov. Murcia - SE. Spain)1966Dekker, L.45(11)Attention is drawn to the discovery of a rudist which surprisingly was found embedded in limestones, developed in the "Couches Rouges" facies. The "Couches Rouges" are usually assumed to have been deposited in relatively deep water, while this rudist must have been derived from a reef, and thus from relatively shallow water. Rudist and sediment are both of Late Cretaceous age.
Note on a Jurassic-Cretaceous section in the subbetic SW of Carvaca (Prov. Murcia, Spain)1966Veen, G.W. van45(11)In the Subbetic, south-west of the town of Caravaca, a relatively undisturbed sequence of Jurassic and Cretaceous calcareous sediments has been found. A number of rock- stratigraphic units have been distinguished in this sequence. Their lithology is described and their ages are discussed.
Further data on oolitic limestones, intercalated in the pelagic sequence of the Subbetic, WNW of Lorca (Prov. Murcia - Spain)1966Rooijen, P. van45(11)Dekker, van Rooijen and Soediono (1966) have demonstrated that during, Aptian-Albian times an area undergoing erosion existed, most probably situated in the Subbetic realm, which supplied detrital material of mainly Jurassic tocks. In the present note it is shown that this situation continued at least until late Albian or early Cenomanian times.
The structural evolution of the Southern Alps1966Bemmelen, R.W. van45(12)The present author has worked in the Southern Alps with students of the Geological Institute of the State University of Utrecht during the past fourteen years (1953-1966). The intent of this work was to test the author's concept of gravity tectonics by means of detailed geological studies of selected areas, statistical analyses of microtectonic elements, and paleomagnetic researches. This testing of the theoretical concept occurred by means of the scientific method of verification, called the "Prognosis-Diagnosis Method". A number of examples are presented as the diagnostic facts of observation, which all confirm the predictions (prognoses) of the concept of gravity tectonics. Therefore, this concept appears to provide an entirely satisfactory model for the mechanics of the structural deformations in this part of the Alps.
The Susacá - interstadial and the subdivision of the late-glacial discussion1966Dreimanis, A.45(12)Late-Glacial interstadials, contemporaneous with the recently introduced Susacá-Interstadial, have been recognized for some time in the Great Lakes Region of North America (the Cary-Port Huron, or Cary-Mankato, or Bowmanville, or Arkona, ending approximately 13,000 B.P.), and in Northern Europe (the Raunis Interstadial, 13,390 ± 500 B.P., and the correlative Plyusna Interstadial). It is suggested that the name Raunis Interstadial be used for the region affected by the North European continental glaciation.
Zircons from some gneisses and granites in the central and eastern Pyrenees1967Kalsbeek, F.; Zwart, H.J.46(1)The presence of many subrounded and irregular zircons in the leucocratic gneisses from the Aston-Hospitalet massif does not indicate a sedimentary origin of these rocks. The gneisses are probably orthogneisses, and the rounding of the zircons is the result of two phases of metamorphism which the rocks underwent. The zircons in the granites of Axles-Thermes and Lys-Caillouas resemble those of the Aston-Hospitalet gneisses, zircons in the granite of the Valle de Aran are different.
On the geology and tectonics of the lake Siljan area, central Sweden1967Stam, J.C.46(1)The tectonic picture of Paleozoic formations, occurring in a ring-shaped structure near Lake Siljan, Central Sweden, is discussed. Evidence, based on the surface geology and the logging of the cores from a number of drillholes, points to the existence of several thrustfaults, which indicates a more complicated structure than believed thus far.
Isotopic age determinations on Surinam rocks1967Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H.46(1)
Orogenfront - verlagerung in Alpen, Apennin und Dinariden und die einwurzelung strittiger deckencomplexe1967Wunderlich, H.G.46(2)The movement of orogenic zones in the Alps, the northern Apennines and the Dinarides and the insertion of rootless nappes. For the Alps, the notthern Apennines and the Dinarides a gradual shift can be demonstrated of the zone of active folding toward the foreland during Cretaceous and Tertiary times. By plotting the development of facies and tectonics in space-time diagrams it is easy to establish that the orogenic fronts were moved askew from the centre to the mariginal parts of the respective orogenic systems. The earlier the start of the synorogenic facies and, accordingly of the folding processes within an orogenic zone, the more central was the position of this zone within the whole orogenic belt. By applying this method it becomes possible to determine the original position of rootless nappe complexes.
The Permian climate in the basin of Lodève, Hérault, France1967Kruseman, G.P.46(2)South of Lodève (Dépt. Hérault) in the southern part of France Lower Permian (Rotliegendes) rocks crop out. Grey Autunian shaes are followed by red beds of the Saxonian. The latter arc generally fine sandy siltstones and claystones, however, in the western part of the region conglomerates and coarse sandstones are present. The sedimentary structures, the texture of the rocks and their mineralogical composition, as well as the remains of the Permian flora and fauna give us the clues necessary for a palaeoclimatic reconstruction. The Autunian was deposited in a swampy environment under a uniformly warm and humid, rain forest climate. The hematite, which provides the red pigmentation, and the detrital material which furthermore builds the Saxonian red beds, were formed in the erosional area under a warm and alternately wet and dry, savanne climate and deposited in the much drier depositional area of Lodève by river and, perhaps, wind action. The differences in climate between the erosional and depositional areas are due to differences in altitude which are a normal phenomenon in a continental environment. Finally, it is tentatively suggested that the wet and dry seasons of the Saxonian found their origin in a summer high pressure and a winter low pressure belt over the East European Permian sea which could have resulted in a wet eastern monsoon and a dry western monsoon, respectively.
Reversal of air flow by a fire - Verslag van de Viith Guiana geological conference 1967Stenuit, R.; Maas, W.; Hammen, T. van der46(2)
Stratigraphy, climatic succession and radiocarbon dating of the last glacial in the Netherlands1967Hammen, T. van der; Maarleveld, G.C.; Vogel, J.C.; Zagwijn, W.H.46(3)Field-data, pollen-analysis and some 30 radiocarbon dates have been the basis for the construction of a climatic curve for the Last Glacial in the Netherlands. The coldest part, the Pleniglacial (between more than 50.000 and 13-14,000 years ago). witnessed at least two phases of a rise in temperature: about 38,000 and 30,000 years ago, the Hengelo and Denekamp Interstadials; the period is classified as Middle pleniglacial. The maximum cold. with polar desert conditions, lasted from about 26,000 to 13.000 years ago. This phase is mainly characterized by the presence of a desert pavement associated with large frost-wedges on top of an arctic soil; organic remains are completely absent. In contrast to other parts of the Last Glacial sedimentation was almost at a standstill. The sequence in Holland is compared with the loess-area of Austria. The Paudorf soil complex can be correlated with the Middle pleniglacial. There is a close resemblance of the climatic curve with palaeotemperature curves obtained from deep-sea sediments.
The alteration of cordierite in spotted schists from the Central Pyrenees1967Bosma, W.46(3)Quantitative data are submitted about the mineral composition of the altered cordierite porphyroblasts appearing as black spots in contact rocks and regional metamorphic rocks from several places in the Central Pyrenees. These spots have pseudohexagonal forms. The combined results of quantitative microscopic and X-ray investigations indicate that the alteration products consist of roughly equal amounts of muscovite and chlorite. These minerals form micro- and cryptocrystalline aggregates, which may resemble the unaltered cordierite in optical properties.
Results and problems in diatom investigation at the geological survey in Haarlem1967Saar, A. du46(3)
Note on the history of a Jurassic turtle skull in the Teyler museum1967Regteren Altena, C.O. van46(3)
Entwicklung des schreitenden ausbaus durch die Bergbauforschungsanstalt1967Loonen, H.E.46(4)In the past five years Staatsmijnen/DSM have experimented, on the surface and underground, with two types of self-advancing support designed by their own staff. The object of the present paper is, on the one hand, to give an insight into the ideas underlying the development programme, and, on the other, to report on the experience obtained.
Bijdrage tot de kwartair-geologie van westelijk Noordbrabant1967Oosten, M.F. van46(4)The article describes certain aspects of the Pleistocene geology of the western part of the province of Noord-Brabant. An old Pleistocene clay layer is mostly present at a depth of a few metres. The surface of the clay consists of a very humic or peaty layer of Eemian age. In a deep erosion valley in the old clay near Breda, the Eemian is represented by a thick peat layer, resting on sand of unknown origin and age. A second peat layer reflecting a cold, arctic flora, probably of Riss- glacial age, has been found in this sand. Fluviatile sands, some with cross-lamination and solifluction phenomena and with thin intercalations of peat containing a subarctic parklandscape flora, arc overlying the Eemian or the old- pleistocene clay. They date from the Pleniglacial A-stage of the Würm-glacial. In the Breda valley this stage is represented by a humic loess also with a peat layer. A highly cryoturbatic loamlayer, called ,,Wouw-Loam" and a medium to slightly coarse-textured sand containing some gravel, on top of this loam, may be of Paudorf-interstadial age or somewhat older or younger, By solifluction and/or fluviatile influence reworked material of the latter is often present as a thin layer of coarse sand with much gravel. A second loess deposit, of the same age or more probably dating from the younger Pleniglacial-B stage, can be found in the Breda-valley. During the Pleniglacial-B stage, the eolian Older coversand was deposited. A thin gravel layer, being a deflation and/or washout horizon of the coarse sand with gravel, marks the sharp boundary between this Older coversand and the underlying horizons. A strongly Loamy coversand, which in many places covets the ,,typical" Older coversand, most probably dates from the end of the Pleniglacial B and perhaps from the transition to the late Glacial (Bølling interstadial) Younger coversand from the Older and Younger Dryas time may also be encountered. The former in a thin layer on top of the Older coversand; the latter only in some places as ridges, sometimes underlain by a formation dating from the Allerød interstadial.
KNGMG Jaarverslag 1966196746(4)
The Mahang formation: a Mid-Palaeozoic euxinic facies from Malaya - With notes on its conditions of deposition and palaeogeography1967Burton, C.K.46(5)The subject of this communication is a rock-stratigraphic unit from northwest Malaya comprised essentially of highly carbonaceous, more or less siliceous, shale and mudstone, with subsidiary arenite, minor chert and very limited calcareous argillite and limestone. The name "Mahang Formation" proposed by Courtier (in manuscript) is now formally adopted for this rock unit in accordance with the American Code of Stratigraphic Nomenclature. Fossil trilobites in the Mahang Formation are considered to be Ordovician, abundant graptolìtes are clearly Lower to Middle Silurian whilst the contained tentaculites appear to be Lower to Middle Devonian in age. Of singular interest is the intimate association of Silurian graptolites with Devonian tentaculites at 15 localities. It is evident that the Mahang Formation corresponds closely to the euxinic facies of Pettijohn (1957). The Mahang basin of deposition seems to have originated upon a platform in Upper Ordovician times with the development of a geanticlinal barrier to the east on the approximate site of the modern Main Range. Shelf conditions probably persisted to the west. Initially there was free communication with the open ocean across the submerged barrier and in the Lower Silurian a graptolitic plankton flourished in the surface waters. As the orogenic cycle developed however, the geanticline was progressively raised until external connections were effectively severed. This isolation is expressed in the apparent absence of Ludlow forms in the prolific Mahang plankton. In the Lower Devonian the geanticline is believed to have collapsed in a chain of islands, whereupon a tentaculite plankton invaded the Mahang basin. Associated orogenic movements may now have caused the surface to become polluted by toxic bottom water, with consequent annihilation of tentaculites. Their shells then sank to the bottom to join a minority of older graptolite and trilobite remains which had been disturbed by the same earth movements. A regional review shows that in the mid-Palaeozoic a geosynclinal tract extended throughout most of the length of Malaya and thence northwards into Thailand. ln Malaya the black shale facies is not known to occur to any considerable extent beyond the Mahang basin, but it reappears near Fang in northwest Thailand.
The Denekamp- and Paudorf interstadials1967Vogel, J.C.; Hammen, T. van der46(5)In this article the stratigraphical position, pollen diagrams and C 14 dates of the Denekamp Interstadial are discussed. The C 14 dates for the Paudorf Interstadial are evaluated, and the most reliable dates and data are compared with those of the Denekamp Interstadial. The conclusion is drawn, that the end of both interstadials is contemporaneous. It is possible, however, that the beginning of the Paudorf Interstadial corresponds to the beginning of the Hengelo Interstadial.
Over stenen-oriëntatie in het Nederlandse keileem1967Boekschoten, G.J.; Veenstra, H.J.46(5)Forty-seven measurements on groups of oriented pebbles in Dutch tills of the Saale Glaciation have been carried out at four localities. The tills possess a variable composition according to their source area and the amount of fluvial gravel that has been taken up from older deposits. No distinct orientation of the erratics could be found. The enclosure of glacial rafts and sand lenses in the tills is a common phenomenon, but a preferred orientation of these enclosures is also absent. Either a primary orientation of the effects in the moraine did not occur, or the orientation disappeared by secondary causes. The latter are summarized in the following. The Dutch boulder clays have been deposited on unconsolidated sediments, chiefly sands. Some boulder clay areas are ice-pushed from various directions by glacier tongues belonging to the oscillating edge of the ice cap. Another cause is decalcification, which is a normal process in the boulder clays of the Netherlands. It must be expected that this leaching has influenced the volume and texture of the boulder clays causing settlement. Finally, the rather thin boulder clay layers were disturbed by cryoturbation, which reached a depth of 1.50 m or more. An interesting side-effect of cryoturbation is the occurrence of disintegrated, but chemically unaltered, gneisses and crystalline schists. Periodical thawing and freezing could account for these rotten stones in the boulder clay.
Dinoflagellates and their stratigraphic use1967Clarke, R.F.A.46(5)
Isotopic age determinations on a biotite granodiorite and a biotite-hornblende diorite in the coastal area west of Accra, Ghana1967Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H. ; Verschure, R.H.; Szumlas, F.46(5)
Remarkable types of mega cross-stratification in the fluviatile sequence of a subrecent distributary of the Rhine. Amerongen; the Netherlands1967Boersma, J.R.46(6)A fluviatile sequence probably laid down in recent times by a meandering distributary of the Rhine system was investigated in a large weir-lock excavation in the present E.-W. alluvial valley of the Rhine. It consists mainly of medium to fine grained sands on a large scale grading fine upwards. The predominant sedimentary structure is a mega cross-stratification with considerable set-length. Its analysis in differently orientated sections brought to light that the fluvial megaripples (dunes), which have given rise to this structure, had straight rather than winding crestlines. A large clayey body (width 20 m, max. height 2.5 m) consisting of silts and clays in regular alternation was found to fill an elongated, channel-like depression. Its lower boundary is convex downward and cuts into the above mentioned sands. Highly uncommon types of mega cross-stratified sets were observed in the upper part of the sandy sequence. Sets of relatively coarse-grained large scale cross-strata are seen to be underlain by, and structurally tied up with fine socalled bottomset layers of considerable thickness. These bottomset layers can have a very complex upbuilding in fact the most complete succession of structures observed in them, covers from top to bottom: 1. straight or wavy lamination, 2. small scale climbing cross-stratification with foresets dipping in a direction opposite to that of the mega foresets, 3. irregular trough-shaped sets with foresets variable in direction and steepness, 4. small scale tabular sets of cross-stratification having the same direction as the mega foresets. The structures 1-4 are considered to have been formed simultaneously in this downstream order at the lee of the megaripple (dune) front by: backflow in the vortex. area (1, 2); irregular currents in the flowimpinge area (3); and coflow downstream of the latter (4); structure 1 is found closest to the front, structure 4 occurs farther away from it. The conditions under which these structures were formed are claimed to be low current velocity together with large supply from suspension as occur on the upper pointbar. A comparison with apparently similar types of cross-stratification described for the Folkestone Beds (Lower Greensands, England) revealed fundamental differences. In fact the structures in the latter formation are now suggested to be due to reversing tidal curents of unequal strength, rather than to concommittant actions of mainflow and backflow in the lee of the megaripple crest.
De oriëntatie van scheve gelaagdheid, rolstenen en elkele molluskensoorten in de zanden van Kruisschans1967Michel, W.F.E.46(6)To find out the relationship between a paleocurrent and the orientation of molluscshells, the Pleistocene "Zanden van Kruisschans 2" north of Antwerp were studied. Maximum dip direction of the trough-shaped cross-bedding (fig. 2, 5 and 6) and orientation of the long axis of pebbles (fig. 8 and 9) were measured to determine the paleocurrent direction. Of four mollusc species which were studied, one species showed random orientation (fig. 11), but the other species, two lamellibranchs (fig. 10 and 12) and one gasteropod (Fig. 13) showed a marked orientation to the paleocurrent that moved 260°-080°. It is even possible to find the paleocurrent direction by only using fig. 10 and 13. Of the bivalve shells, 87% lies with its convex side up because this is the most stable orientation in a current as fig. 14 and 15 clearly show.
Over de daling van het Noordzeegebied1967Collette, B.J.46(6)
Development of the North Netherlands gas discovery in Groningen1967Ruiter, H.J. de; Laan, G. van der; Udink, H.G.46(7)The discovery well of the Groningen gas field was drilled in 7959. At the end of 1963, when more wells had been drilled, and a re-interpretation of seismic data had been made, the large size of the field became apparent. At present proven reserves are estimated at 1650 x 109 m3 (58 x 1012 ft3). The favourable properties of this huge sandstone reservoir (permeability 0.1 - 1 Darcy) and the results of the first production tests led to the decision to concentrate the wells in "clusters" (groups of closely spaced wells). After the first clusters of 6 to 8 wells with a capacity of 6 x 106 m3/day per cluster had come on stream, field tests and additional studies indicated that larger clusters would be possible. Future field observations may lead to further adjustments in the drainage pattern. In order to solve the complicated problem of optimization of the field's development, mathematical reservoir and economic models are being programmed for an electronic computer.
Depositional sequences and sand distribution in a deltaic complex1967Oomkens, E.46(7)The post-glacial delta complex of the Rhône river is a sediment lens in which, volumetrically, coastal-plain deposits and marine deposits are almost equally important. An analysis of the lithological relationships shows that the deltaic sediments can be grouped in one of the following depositional sequences: 1. Regressive sequences 2. Channel-fill sequences 3. Transgressive sequences. Regressive sequences are due to a process whereby sediment-laden river water enters a basin that is filled with water of higher density (e.g. sea or lagoon). This process produces a sediment body that contains finegrained sediment at its base and dominantly coarse grained sediment at its top (upward coarsening). The topmost sand member may reach a thickness of 10 metres. The sand is deposited in sheets hundreds of square kilometres in extent. The sand has a gradational contact with the underlying marine clay. Channel-fill sequences are due to a process whereby a decrease in current velocity occurs in a channel. This process produces a sediment body that contains coarse grained sediment at its base and dominantly fine-grained sediment at its top (upward fining). The basal sand member varies widely in shape and texture. Commonly the sand member is elongate and has a width/thickness ratio of as much as 1000. Transgressive sequences are due to a process whereby the rate of subsidence exceeds that of sedimentary buildup. This process leads to deposition of a sediment body in which coastal-plain deposits are overlain by coarse grained coastal-barrier deposits (upward coarsening) what are in turn overlain by marine deposits. The sand member varies in thickness but is seldom more than 2 metres thick. It occurs in sheets. The sand commonly has a gradational contact with underlying coastal-plain clays.
The duality of orogenic belts1967Zwart, H.J.46(8)A twofold classification of the orogenic belts of the word is proposed, based in first instance on the facies series of the metamorphic rocks. The Hercynian and Alpine orogens of Europe are reviewed in detail and are found to differ respectively in several ways: (1) low pressure metamorphism with andalusite and cordierite vs. high pressure metamorphism with glaucophane, sodium pyroxene, lawsonite and kyanite, (2) thin vs. thick metamorphic zones, (3) abundant vs. few granites and migmatites, (4) few vs. abundant ophiolites and ultrabasites, (5) broad vs. narrow orogen, (6) small vs. large uplift, (z) scarce vs. dominant nappe structures. The Caledonian orogen of Europe is examined and found to be intermediate in nature between the "Hercynotype" and "Alpinotype" orogens. The Svecofennian- Karelian belt of the Baltic shield is found to be a typical Hercynotype orogen. The paired metamorphic belts of the Circumpacific region appear to be a new element in the earth's history and tend to emphasize the peculiar character of the Pacific Ocean. It seems probable that the thermal history of the earth has not appreciably changed during the last 2500 million years. The pressure-temperature fields of the various facies and facies series based on field and experimental work are discussed. Finally the causes of regional metamorphism are considered.
In Memoriam Professor Pierre Pruvost196746(8)
Van de voorzitter1967Sitter, L.U. de46(9)
In memoriam - Dr. P. Kruizinga1967Faber, F.J.46(9)
The late Tertiary peneplain of South Limburg (The Netherlands) silifications and fossil soils; a geological and pedological investigation1967Broek, J.M.M. van den; Waals, L. van der46(9)South Limburg formed the border-zone of a large West European peneplain during the Tertiary and the Late Tertiary. Thin local deposits of strongly weathered and corroded sand and gravel, strongly weathered outcrops of underlying formations, deep fossil soils and extensive surface silicifications are the characteristic features of this peneplain. Through a combined geological and pedological survey these features were found to be interrelated. They are the result of typical climatic circumstances and the associated vegetation acting on the earth surface. Such influences can leave their marks on the surface only during a period of geological calm: a period without any noticeable sedimentation or erosion. Such periods generally escape a geologist's observation; they Me of utmost importance to the soil scientist. In South Limburg the Late Tertiary peneplain is partly covered by Pleistocene Maas deposits (in the western parts); the rest of this surface is dissected and remodeled during the Pleistocene (the eastern part). From our systematic inventory a tentative description can be given of the important features of the environment during these times. In the long periods of geological calm a strong weathering developed as a result of a warm, humid climate with dry periods of several weeks. Erosion has been unimportant and restricted mainly to the strongly weathered surface material, This material has been shifted over short distances only. A thin discontinuous sheet of sediments developed on the peneplain, that has been named the Basal gravel complex. The deposits of the borders of the peneplain and of the contiguous graben are much thicker and easier to enravel stratigraphically. This fringe area has been called the accumulation region. Soil forming processes have produced rather deep soils on the peneplain as well as in the deposits of the Basal gravel complex. Mobilisation of silica produced extensive surface silicification of limestones and in well drained clayless sands; these features compare favourably with the silcrete duricrusts in other parts of the world. In South Limburg the peneplain is later transformed by erosion, furrowing, the influences of frost periods and the covering with younger sediments during the Pleistocene. In other parts of the world such fossil table lands are much better conserved because the climate became more arid.
The role of micro-crack systems in the spheroidal wheatering of an intrusive granite in galicia (NW Spain)1967Bisdom, E.B.A.46(9)The phenomenon of spheroidal weathering is related to the development of micro-crack systems. Between the "unweathered coarse granite" of zone 1 and the boulder surface a "limonite" band can be distinguished, which can be divided into two zones (2 and 3) according to the pattern of the micro-cracks. Scales are formed in zone 1 along cracks lying roughly parallel to the boulder surface and becoming macro-cracks in zone 4, where the scales are released. The results of this study of the crack system formed during the spheroidal weathering of a coarse-grained granite throw doubt on theories that explain the spheroidal shape as being due to either magmatic cores or the release of confining pressure. Two terms are used in a special sense in this paper, viz. concentric banding, resulting from the crack system involved in spheroidal weathering, and ghost structure, which is here defined as the phenomenon seen in a regolith in situ after the boulder has completely weathered away.
Seismic profiling in the North Sea Basin1967Lagaay, R.A.; Collette, B.J.; Schouten, J.A.46(10)Seismic sections of the upper sedimentary layers and an isochron map of the base Tertiary in the southern part of the North Sea basin are presented. They are the result of an instrument testing program with an air gun profiler. Several structural features of the Cenozoic can be correlated with the geology of adjacent areas. An important aspect of the formation of the North Sea basin is the differential sagging, leading to the formation of subbasins that shift place in time.
Flat-bottomed glacial valleys, braided rivers and the beaver1967Rutten, M.G.46(10)Flat-bottomed glacial valleys on the northern continents owe this feature not to aggradation by braided rivers, but to the beaver.
On the occurrence of the scyphomedusa in the Cambrian of the Cantabrian mountains (NW Spain)1967Meer Mohr, C.G. van der; Okulitch, V.J.46(10)
In defense of the Orbulina datum1967Soediono, H.46(10)Brandy's suggestions that Orbulina is biphyletic and the Orbulina datum diachronous are rejected
Isotopic age determinations on granitic rocks in Northern Portugal1967Priem, H.N.A.; Boelrijk, N.A.I.M.; Verschure, R.H.; Hebeda, E.H. 46(10)
Seventh international sedimentological congress, Great Britain 19671967Jong, J.D. de46(10)
Das paläozoikum im gebiet zwischen San Benito und Torrecampo (Sierra Morena/Spanien)1967Puschmann, H.46(11)A section published by Triguero (1961) from the area north of Torrecampo (Prov. Córdoba) was remapped. Some different stratigraphic and tectonic points of view resulted from this investigation. Bed rocks were identified as the "Armorikanische Quarzit" (deep seated Ordovician) up to the deep lying part of the Lower Carboniferous series in the area which is highly tectonically disturbed. Facies and stratigraphy correspond to those of northern Sierra Morena. A stratigraphicaI break includes the higher Siegen, Ems and Middle Devonian. (Triguero, however, suggested a stratigraphical break from Ludlow up to Siegen.) Upper Devonian (Frasnien) Iies conform on the Siegen-Quarzit (deeper seated Siegen) contrary to the former conception.
Sense of fault displacements1967Tjia, H.D.46(11)The direction with smoother touch along a fault plane parallel to the slickensides does not invariably correspond with the direction of fault displacement. There are more fault plane features which produce coarser touch in the direction of motion than there are markings which feel smooth in that direction; therefore, the smoother touch criterion for interpreting fault movements should be discarded. Excellent directional indicators on fault planes include: Prod marks, tension fractures and associated steps, crescentic gouges, the attitude of secondary shear fractures, chattermarks, and knobbly protuberances resembling "roches moutonnées". Separately the following markings are not reliable, because similar-looking features may be caused by more than one process: Pluck marks and steps formed through stick-slip and spalling; triangular scratches and bruises; spurs and trails; drag which may have experienced elastic rebound.
Sur la présence d'éléments du Bétique de Málaga au sud de la Sierra Nevada, près de cherín (Espagne Méridionale)1967Bodenhausen, J.W.A.; Fontboté, J.M.; Simon, O.J.46(11)
The relation between the Betic of Málaga and some post-eocene formations in the area near la Fuensanta-La Parroquia (Provincia de Murcia, SE Spain)1967Geel, T.46(11)An interpretation of the geology of the La Yesera and El Cimbre locations near Fuensanta-La Parroquia is given, which differs from that of Fernex et al. (1965). In La Yesera evidence has been found for major tectonic movements which took place in the interval between the deposition of Bolli's (1957) Globorotalia kugleri Zone and the lower part of Bolli's (1957) Globigerinatella insueta Zone, that is probably in the upper Oligocene-lower Miocene.
A comparative table of recently published geological time-scales for the Phanerozoic time - explanatory notice196746(11)
In memoriam - Prof. dr. B.G. Escher196746(12)
L'Unakite du cotentin1967Escher, B.G.; Plas, L. van der; Veen, A.H. van der46(12)
Geometrical and time relationships for three fold systems and a subsidiary movement phase in metamorphic rocks south of Bagnères-de-Bigorre, French Pyrenees1967Read, R.A.46(12)In an area of differential, regional metamorphism, the main aspects of the structural history are basically similar to those established for the eastern Pyrenees (Zwart, 1963a), and are related to at least two generations of folding and an intermediate phase of deformation. The first period of folding is associated with an axial plane slaty cleavage and has produced the most prominent structures in the region (EW trending). Two sets of small scale, asymmetric folds are associated with axial plane, strain slip cleavages (NS and EW striking) and post-date first phase structures. These later generation fold systems show differential development on all scales and although, in certain instances, they can be physically distinguished, their chronological relationship remains undecided. Andalusite and staurolite porphyroblasts grew between the first and second phases of deformation and have internal fabric configurations compatible with a period of movement occuring towards the end of the growth period of the porphyroblasts and involving renewed slip on the first phase cleavage about NS trending axes of internal rotation. This subsidiary movement phase appears to be kinematically related to the NS striking strain slip cleavage system. A concept of large scale internal rotation associated with the strain slip cleavage systems is basically consistent with derivation of flat-lying first phase cleavage orientations from initially steeper attitudes.
A rapid reconnaissance of the main clay mineral provinces in the Guyanas1967Brinkman, R.46(12)Major differences in clay mineralogy correspond to the major landscape boundaries in the Guyanas. Two of the landscapes have a rather uniform clay mineral composition and two are more variable. Small amounts of accessory non-clay minerals occur in the clay fraction of many samples; clay-size quartz is generally present. The young coastal plain and the tidal river (estuary) alluvium belong to a rather uniform clay mineral association containing a mixture of smectite, illite and kandite with a cation exchange capacity of about 40-50 me/100 g clay. Parent material appears to be Amazon mud reworked by the sea. The old coastal plain is a complex of three clay mineral associations containing smectite, illite and kandite; illite and kandite; and kandite. The last two of these have exchange capacities of about 25-35 me/100s clay. The three associations may have a common parent material similar to that of the young coastal plain; the variability may be caused by acid destruction of part of the clays due to pyrite oxidation. The white and Brown Sands plateau appears to be part of one vast uniform clay mineral association, also occurring in Brazil and containing kandite with very low exchange capacity: 2-4 me/100g clay. The low exchange capacity may have been caused by differential transport seaward of the finest clay fraction during deposition of the sediments. The interior residual and alluvial areas consist of two clay mineral associations, containing kandite with or without illite. Exchange capacities are about 10-20 me/100g clay.
Vergleich des "vetschauer-kalkes" der Aachener kreide mit dem Kreide-profil von Süd-Limburg anhand von coccolithen1967Vangerow, E.F.; Schloemer, W.46(12)By making use of Coccolith spectra an attempt is made to compare the "Vetschauer Kalk" of the Aachen cretaceous and the "Kunrade chalk" with the wellknown chalkprofiie of the Maas Valley. Most likely 'we may assume that the "Vetschauer Kalk" corresponds only with the lowest Maastricht Chalk, i.e. the lower part of the foraminiferal zone H, whereas the "Kunrade Chalk" belongs to the region of foraminiferal zone H - K. The Postmaastrichtian Chalk from Houthem shows a distinct floral cutting as opposed to the subjacent Maastrichtian layers. So this chalk might be attributed to the Danian.
Upper Cretaceous larger foraminifera in the subbetic south of Caravaca (Prov. Murcia - SE Spain)1967Veen, G.W. van46(12)Fragments of larger Foraminifera have been found in sandy intercalations of an Upper Cretaceous pelagic limestone sequence of the Subbetic south of Caravaca. The author believes that these larger Foraminifera have been derived from the Prebetic in the north, and emplaced by turbidity currents.
De laatglaciale geschiedenis van het verwilderde riviersysteem ten zuidwesten van Nijmegen1967Teunissen, D.; Oorschot, H.G.C.M. van46(12)A study was made of the peat in the beds in the central part of a fossil braided river system of Würm- (Wisconsin-) glacial age in the vicinity of Nijmegen (Guelderland province, The Netherlands). The results of these investigations point to the fact that this system was vacated by the rivers Rhine and Meuse in late glacial times. The dispersal- and gathering channels were abandoned in the beginning of the Bølling Interstadium and the main channels in the beginning of the Allerød Intersadium. After that time, the gathering channels drained away the rain and melted snow of the region, because they were situated in a faint depression in the landscape. Thus the filling material in the gathering channels remained more or less sandy until Boreal times whereas, for a long period prior to that, the mean channels had been filled with peat deposits. After the end of the Boreal all investigated channels have filled exclusively by peat until Subboreal or Subatlantic times.
Relation between Neogene sedimentation and late orogenic movements in the eastern Betic Cordilleras (SE Spain)1967Völk, H.R.46(12)Essentially the sedimentary rock sequence of the Neogene basin of Vera in south-east Spain can be divided into an older and a younger group of formation, which are separated by an angular unconformity. Both groups are clearly distinguished by a different deformational pattern and a different detritus composition. In the Younger Neogene formations – in contrast to the Older ones - a striking domination of clastic components were found originating from higher grade metamorphic rocks of the deepest tectonic units of the Betic orogene, viz. the "Nevado-Filabrides". The almost complete lack of higher metamorphic clastic material in the Older Neogene formations together with the absence of these older formations along the western margin and the adjacent uplands of the Vera basin - as far as it is bordered by rocks of the "Nevado-Filabrides" - points to a rapid uplift of the central Betic zone in Middle Miocene times (VöIk 1967, p. 136/137. These movements are supposed to have affected large parts of the eastern Betic Cordilleras. Further arguments are advanced for a tentative correlation with the "younger phase of the later tectogenesis" (Voet), 1967)2 of the Betic orogene as working hypothesis.
Change of command1968Jong, J.D. de47(1)
On criteria for the continuance of flute marks, and their implications1968Allen, J.R.L.47(1)A consideration of the structure of the region of separated flow generated at a negative step when Reynolds numbers are large, and of the mechanics of the turbulent suspension of sediment, leads to two criteria for the continued growth of flute marks fashioned on a mud bed by a current. These marks are well known from turbidites, and are not uncommon in other sedimentary facies. The criteria have the general form Ucrit=f1(Vg) = f2(D) in which Ucrit is the critical flow velocity of a current bearing sediment of physical size D or of effective falling velocity 4, Flutes continue to grow provided that U > Ucrit but when U < Ucrit become infilled with grains or completely covered over by a grain layer. Alternatively, the criteria can be expressed in terms of flow power, whence an inverse correlation emerges, in the case of turbidites bearing flutes, between the Bouma division which begins the turbidite and a characteristic value of D for that division.
Isotopic age determinations on Surinam rocks, 3. Proterozoic and Permo-Triassic basalt magmatism in the Guiana shield1968Priem, H.N.A.; Hebeda, E.H.; Boelrijk, N.A.I.M.; Verschure, R.H.47(1)K-Ar measurements show that basalt magma has intruded the basement rocks and Roraima deposits in Surinam (Dutch Guiana) 1690 ± 100 m.y. ago (Early to Middle Proterozoic) and 221 ± 10 m.y. ago (Lower Triassic or Upper Permian). The Permo-Triassic dolerites are augite dolerites rich in iron ore and with K/Rb ratios between 267 and 309. The Proterozoic dolerites carry hypersthene in addition to augite, contain less iron ore and have K/Rb ratios between 128 and 233.
A new concept of the Paleotectonic set-up of a part of northern Peninsular India with special reference to the great boundary faults1968Tewari, A.P.47(1)Existence of a deep/fundamental fault in parts of the Mirzapur district, Uttar Pradesh, India, which lies along the northern limits of Peninsulat India, has been examined in places by the author. The fault, which is trans-subcontinental in dimension and recurrent in activity, gives a sharp tectonic break in Peninsular India, and not only divides the Vindhyans from the Pre-Vindhyans (Flysch and Molasse Formations) but also limits the extension of the lower-Gondwanas in Peninsular India, Hence the author feels that it should be designated as a Great Boundary Fault, Westward extension of the Great Boundary Fault through the vast area covered with the Deccan Trap, leads one to believe that this fault has provided channel for the upwelling of the Deccan Trap. It is interesting to note that earlier (1938), Heron had established a similar fault over a length of 800 KM in Rajasthan. He did not, however, discuss the lateral extension of the fault towards the south when it was lost under the Trap country. The author is led to believe that the Great Boundary Fault of Rajasthan swings to the east to form the Narmada-Son valleys, now filled with Pleistocene and alluvium terraces, and extends not only in the Mirzapur District under an identical geological set up and tectonic framework but also continues eastwards to the Palamau and Gaya districts of Bihar. With this correlation the author has deciphered a new tectonic picture of northern Peninsular India, The author is also of the view that this new concept would be helpful in deciphering the continuity of the important sulphide and other mineralized belts/zones of Rajasthan in the Mirzapur district and their correlation with that of the Bihar area. The author also points out in this paper the possibility of crustal folding involving the Vindhyans and the Pre-Vindhyans together with the Great Boundary Faults along the southern fringe of the Bundelkhand massif. If this view is accepted the possible age of this Great Crustal Fold could be related to the Hercynian orogeny, which is based on the distribution of the marine Permo-Carboniferous fauna along a great regional arc (i.e. between Bap in Rajasthan, Umaria and Manendragarh in Madhya Pradesh and Daltanganj in Bihar).
Coal rank and lowest-grade regional metamorphism in the souther Bowen Basin, Queensland, Australia1968Kisch, H.J.47(1)The mineralogy of sedimentary rocks associated with Upper Permian coals in eastern Queensland, ranging in degree of coalification or “rank” from medium-volatile bituminous to semi-anthracite, is described. Kaolinite is the predominant clay mineral associated with the lower-rank coals: chlorite is absent and siderite is the predominant carbonate. At Bluff chlorite makes its appearance in a kaolinite tonstein in coal with 89% carbon. In the shales, feldspathic wackes, and tonsteins associated with the Baralaba semi-anthracites (90-91,5% carbon), kaotinite has completely given way to chlorite and illite, and ankerite is the major carbonate. The previously described chlorite-dioctahedral 1M illite crystal tonsteins at Baralaba (Kisch, 1966a) are probably laterally equivalent to kaolinite tonsteins in medium-volatile bituminous coal at Moura. The absence of zeolites from the rocks investigated is considered to reflect the high μCO2/μH2O chemical potential ratio during burial metamorphism. The coal rank in association with which chlorite and illite formed at the expense of kaolinite at Baralaba is higher than that at which laumontite-rich assemblages appear in tuffs and volcanic sandstones in the Sydney Basin of New South Wales (Kisch, 1966b). Coal rank may be an important aid in correlating burial metamorphic assemblages in areas with and without zeolites, and other hydrous calciumaluminosilicates.
A geological reconnaissance in the Nassau range, West new Guinea1968Dow, D.B.47(1)In 1961 an attempt to make the first climb of the Carstenz Pyramid in West New Guinea ended in failure, but during the approach to the mountains much new country on the northern side of the Nassau Range was explored. The observations made during the trip are the only geological information at present available for a large area of the Nassau Range. Remarkably clean quartz sandstone of probable Mesozoic age forms the basement on which Lower Tertiary marine sediments were deposited, probably unconformably. Faulting commenced at an early stage of the sedimentation, breaking the area into a series of horsts and grabens which had a considerable influence on sedimentation. The sedimentation was punctuated, probably in the Lower Miocene, by andesitic vulcanism. Well-preserved erosion features and moraine deposits due to a late Pleistocene glaciation are found over about 12,000 feet: there is also some evidence of an earlier glaciation. The Tertiary rocks are generally only gently folded but they are dislocated by long, slightly curved, faults of considelable vertical displacement. They show many feature characteristic of transcurrent faults, and it is possible that horizontal movement on the faults was predominant.
Discussion; On A geological reconnaissance in the Nassau range, West new Guinea1968Visser, W.A.47(1)
Geomorphology and sedimentary petrology in the southern gulf of St. Lawrence 1968Nota, D.J.G.47(1)
Paleomagnetisme en aardexpansie1968Hospers, J.47(1)
Invalidity of the billiton granite, Indonesia, for defining the Jurassic/Upper Triassic boundary in the Thai-Malayan orogen1968Strachan Hutchison, C.47(1)The Billiton granite is shown both stratigraphically and radiometrically to be invalid for setting the base of the Jurassic at 180 ± 5 m.y.. A review of the nore recent stratigraphic and radiometric developments in this region shows that the evolution of the Thai-Malayan orogen and the emplacement of the “tin-belt” granite is much more complex than the model upon which the age of the Billiton granite was based.
Comments on: Invalidity of the billiton granite, Indonesia, for defining the Jurassic/Upper Triassic boundary in the Thai-Malayan orogen, by C.S. Hutchison1968Schürmann, H.M.E.47(1)
Notulen van de Buitengewone Ledenvergadering196847(1)
The Papuan geosyncline and the concept of geosynclines1968Hermes, J.J.47(2)The geologic history of the Papuan geosyncline is shortly described. Attention is drawn to the fact that due to the collision between the Asian and the Australian continent, a segment of the size of the Papuan geosyncline was torn loose, and both bent and broken, leading to the present sinuous shape of the western part of the island (fig. 5). It is suggested that some other sinuous mountain chains may have acquired their present shape in this manner. The development of the Papuan geosyncline is compared with the model of Aubouin based on the Hellenides of Greece and that of Dietz based on his interpretation of the Atlantic CoastaI Plain geosyncline. Important differences exist between the three models. The nomenclature of geosynclines is discussed.
Mineralogical composition of material less than 500 micron from a red and grey boulder clay sample in the Netherlands1968Riezebos, P.A.47(2)Methods devised to collect mineral data for specific purposes have sometimes been used rather indiscriminately in weathering, sedimentological and soil studies. This may partly be due to insufficient knowledge about the dispersion of mineralogical information within the sample material. As an illustration of such a distribution the results of a fractionated optical analysis of light as well heavy concentrates from two well-known glacial deposits ale here presented. At the same time the results of an ore microscopic analysis of the opaque grains in the heavy concentrates from the total 50-500 micron size range are given.
On the geology of San Andres islands, western Caribbean1968Milliman, J.D.; Supko, P.R.47(2)San Andres Island is an uplifted limestone island in the Western Caribbean. Analogy with the surrounding islands and nearby mainland of Central America suggests San Andres to have a volcanic base, although bathymetric and magnetometer data indicate it to be deep-seated.
A late-glacial volcanic ash deposit in southeastern Belgium1968Hulshof, A.K.; Jungerius, P.D.; Riezebos, P.A.47(2)A volcanic ash deposit was found in a peat bog in the Semois valley near Arlon, Belgium. Palynological evidence points to an Allerød age. The volcanic minerals in Belgium and Luxembourg have previously been correlated with ash deposits of the same age in central Germany which resulted from eruptions in the Laacher See area at a time of westerly winds. Although the Laacher See is not excluded as a possible source of origin, the ash in Belgium differs from known Laacher See deposits in relative importance of brown amphibole and sphene, and absence of volcanic glass and pumice ("Bims”). The ash is the product of an eruption in the Eifel region during a period of northeasterly wind.
Note on the formation of stylolites1968Schot, E.H.; Park, W.C.47(2)
Pre- or post-induration formation of stylolite seams: a reply1968Manten, A.A.47(2)
Pollen analysis at the Cueva del Toll, Catalonia: a ctritical re-appraisal1968Butzer, K.W.; Freeman, L.G.47(2)The published paleo-environmental data from the Cueva del Toll are discussed. The two pollen profiles by Donner-Kurtén and by Florschütz-Menéndez refer to the same stratigraphic units although there are small but ecologically significant differences between these profiles. The faunal evidence suggests strongly that the pollen sequence covers part or most of the Last glacial, as suggested by Donner and Kurtén. However, the climatic interpretation suggested by these authors to account for the fluctuations of AP: NAP pollen ratios seems open to question.
Evolutie van een embryo1968Vlerk, I.M. van der47(2)A worldwide correlation based on an association of genera of larger foraminifera is unreliable. It proceeds from the wrong assumption that all these genera lived in the same milieu. Instead of this method of correlation another one is introduced. It is based on the experience that the curvature of the wall between the first and second chamber of the embryo of a megalospheric Lepidocyclina increases persistently when going from older to younger strata. This parameter is called the "degree of curvature”. Investigations on both lepidocyclinas and planktonic foraminifers (by J,A. Postuma; see: Proc. Kon. Ak. Wet. Amsterdam, B,4, 1967,391-398) from a well documented section in East Java & Madura and 5 localities in Europe and America, combined with the examingation of lepidocyclinas from Chattian, Aquitanian and Burdigalian localities in Europe led to the hypothesis: “same degree of curvature’ = same age”. Starting from this hypothesis the following conclusions are drawn (see table): 1 the boundary Oligocene/Miocene should be placed in the Globorotalia Kugleri - zone. 2. the Tertiary-e5 of the Far East is to be correlated with the Chattian, the Aquitanian and part of the Burdigalian of Europe. 3. the boundary Tertiary e/f should be placed within the Burdigalian. 4. the lepidocyclinas from an Aquitanian and from a Burdigalian locality in Europe have “degree's of curvature” which do not differ significantly (Student's t-test).
The Lembang fault, West Java1968Tjia, H.D.47(2)The Lembang fault consists of a northward scarp, exposed over 22 kilometers, which in general strikes parallel to Java's longitudinal axis. Former investigators have attributed predominantly dip slip displacements to this fault. However, topographic, morphologic, and structural evidences indicate the western part of the Lembang fault, west of the Tjikapundung valley, during its latest development to be essentially strike slip in nature and possessing sinistral sense, The horizontal displacement ranges between 75 m and 250 m with an average of 140 m. Using the latter figure, it is found that the annual displacement amounts to at least 3 centimeters. The average ratio of strike slip to dip slip is 2 to 1, which is in agreement with the youngest recorded movement. The eastern part of the fault between Maribaja and Mount Pulusari is a dip slip fault and has exposed throws which range from 130 m to 450 m. Three important, tranverse faults caused the crestline to increase stepwise in elevation from west to east.
Recent sediments in the eastern part of the lake Geneva (Lac Léman)1968Houbolt, J.J.H.C.; Jonker, J.B.M.47(2)The sedimentation in the eastern part of the Lake of Geneva was studied from cores and seismic profiler records, It was found that off the mouth of the Rhône river a sublacustrine channel with natural levees leads down to a depth of about 200m. The channel bottom and natural Ievees were found to be sandy, but outside the natural levees mud was encountered. Below a depth of about 200 metres the natural levees along the channel disappear and sand layers are found in the vicinity of the channel. The channel disappears completely at a depth of about 280 m. Around and below the point where the channel fades out, a fan-shaped sand body occurs, which reaches to the deepest part of the Lake, the central plain, at 309 m. The sediments on this central plain contain only a few very thin sand layers. The bottom of the sediment fill of the Lake was found to plunge to the east, The “top Molasse” reflector was lost halfway up the delta foreslope, at about 750 milliseconds.
Mineral assemblages in Rotliegendes1968Booy, T. de47(2)
Surface installations and operations1968Bijl, P.C.J.47(2)
Edelstenen en hun dubbelgangers1968Zwaan, P.C.47(2)
Exploration and delineation of the Groningen Gas Field1968Groen, D.M.W. te; Steenken, W.F.47(2)
Petrophysics Groningen Gas Field1968Laan, G. van der47(2)
Reservoir behaviour and field development Groningen Gas Field1968Udink, H.G.47(2)
Drilling experience Groningen Gas Field 1968Bor, A.M.W.47(2)
Subsurface installations and operations Groningen Gas Field1968Willems, J.F.J.47(2)
On the character and classification of bed forms1968Allen, J.R.L.47(3)A bed form is any deviation from a flat bed, that depends for its origin on an interaction between a bed material and a fluid flow such that there occurs a spatially non-uniform transfer of material from bed to flow or between bed and flow. The occurrence of bed forms is independent of the precise nature of the fluid, whether a liquid or gas or a flow of granular matter, and also of the nature of the bed material, whether cohesionless or cohesive. In nature bed forms are generated by the wind and by sand avalanches, as well as by river, wave and tidal currents. Bed forms arise on surfaces of loose sand or gravel, on beds of mud or rock, and on surfaces of ice or hardened snow. An analysis of the more important of the determinative physical processes allows bed forms to be classified according to: 1) the orientation of the form and the directional properties of the parent flow system, 2) the character of the boundary on which the form arises, and 3) the dependence of the scale of the form on the scale of the parent flow system. By an application of these criteria, bed forms hitherto treated disparately are brought into revealing juxtapositions that suggest where general explanations of bed forms can be obtained in future.
Geology and Paleomagnetism of an anticlinal structure in Lower Triassic sediments near Atienza (Guadalajara, Spain)1968Voo, R. van der47(3)The results of detailed geological mapping in an anticlinal structure of Lower Triassic sediments are presented. For paleomagnetic studies 60 samples were collected of fine-grained red sandstones and their magnetic behaviour is analysed. Most of the samples contained only one type of magnetization, directed along the recent local geomagnetic field, and it is assumed that these magnetizations are secondary. About 25% of the samples appeared to have stable magnetizations with directions diverging from the present-day geomagnetic field in Spain. These directions, however, proved not to be characteristic for the Triassic geomagnetic field, since after unfolding their data were inconsistent.
Isotopic age determinations on surinam rocks, 4 ages of basement rocks in North-Western Surinam and of the Roraima tuff at Tafelberg1968Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verschure, R.H.; Verdurmen, E.A.T.47(3)(1) Rb-Sr measurements show that in the Avanavero region (Kabalebo River, north-western Surinam) deposition of the Dalbana and Matapi volcanics, and subsequent emplacement of the granite-quartzdiorite batholiths took place in a single orogenic period, approximately 1800-1900 million years ago. Since the Dalbana volcanics are generally correlated with the Iwokrama Formation in Guyana, this raises some doubts on the K-Ar age of (2595 ± 125) x 106yr measured on riebeckite from the Makarapan Granite intruding the Iwokrama Formation (Snelling & McConnell, 1966). (2) A (1200 ± 100) x 106yr old metamorphic event, designated as the Nickerie Metamorphic Episode, caused widespread rejuvenation of micas in north-western Surinam. Probably, a long, broad belt of overprinted age values down to (1200 ± 100) x 106yr extends from south-eastern Guyana east-to-eastnortheastward through Guyana and northeastward through Surinam to the Atlantic coast. (3) Rb-Sr and K-Ar age determinations on a tuff from the Roraima Formation at Tafelberg, central Surinam, point to an age of (1610 ± 60) x 106yr. Probably, both Roraima sedimentation and subsequent dolerite intrusions took place, approximately, 1600-1700 million years ago.
Mineral analysis by means of thin layer chromatography using liquid ion-exchangers. Part III Data on non-sulphidic minerals1968Sijperda, W.S.; Vries, G. de47(3)Using the rapid chromatographic technique described in part I 25 minerals have been analyzed. in order to obtain data concerning detection and Rf value
The age of Eifel Maars as shown by the presence of Laacher See ash of Allerød age1968Jungerius, P.D.; Riezebos, P.A.; Slotboom, R.T.47(3)Laacher See ash of Allerød age, with a characteristic heavy mineral assemblage of brown amphibole, pyroxene and sphene, occurs as intercalations in the peat bogs of the western Eifel. Previously this ash has been attributed to eruptions of local maars and has erroneously been used to date these maars. It is here shown that the maar volcanism of the western Eifel terminated prior to the final Laacher See eruption.
Das Quartärprofil von Kärlich/Neuwieder Becken1968Brunnacker, K.47(3)The Quaternary deposits in the clay-pit of Kärlich near Koblenz have been re-examined. There are two gravel beds at the bottom, followed by a loam of back swamp deposits. They are followed by loess beds of some glaciation phases, the lowest of which is far more complex than the others, similar as has been found at Regensburg3Bavaria. The loess beds can be correlated with the four classical Alpine glaciations. A more detailed description is under preparation.
Geologische waarnemingen op de Noordzee1968Heybroek, P.47(3)
Geologische waarnemingen op de Noordzee1968Heybroek, P.47(3)Big plate F1
Geologische waarnemingen op de Noordzee1968Heybroek, P.47(3)Big plate F2
Geologische waarnemingen op de Noordzee1968Heybroek, P.47(3)Big plate F3
Het boren naar olie en gas op zee1968Buskingm B.E.; B.I.P.M.47(3)
A new coring apparatus for unconsolidated sediments1968Overzee, B.47(3)
Recent sediments in the southern Bight of the North Sea1968Houbolt, J.J.H.C.47(4)The recent sediments of the southern bight of the North Sea were studied mainly as a possible model for the interpretation of fossil sand bodies, The area examined lies between England, Belgium and the Netherlands. It is an area of strong tidal currents. A group of ridges were found to consist of sand and to rest on an essentially flat surface which is a continuation of the surrounding sea bottom. The ridges of the Well Bank area are asymmetric in cross section and are oriented parallel to the current direction. Sand seems to be transported obliquely over the gentle southwest slope of the ridges in a northerly direction towards the crest, whence it is deposited on their steeper northeast flank. This process gives rise to an internal cross-stratification which is visible on the sparker records. The ridges of the Well Bank area seem to be moving slowly northeastwards. Sparker records of the ridges formed by sand accumulation outside the WelI Bank area revealed no internal structures and foreset directions observed in cores of them were found to be erratic and their asymmetry in cross section was found to be irregular. It is therefore impossible to deduce their internal structures from surface observations. It is certain, however, that they are all isolated sand bodies standing on a flat subsurface that is exposed outside their flanks. The fact that the flood current does not follow the same path as the ebb current gives some of these ridges very complicated forms (e.g. Flemish Banks and Haisborough Sand), In all cases, it can be stated that the sand of which these sand ridges consist is derived from the sea bottom and not directly from a river mouth. The sand in the ridges of the WeII Bank area seems to have been derived from a glacial outwash fan formed in the area during the last glaciation. The material in the Outer Gabbard and probably the other ridges in the neighbourhood is derived from Tertiary sediments outcropping in that area. The sand in the Flemish Banks, the Hinder Banks, the Sandettie and the Falls is derived from Rhine sands deposited in the area during stages of lower sea level. The Brown Ridge and the Zeeland Ridges were found to have been formed at least partly by erosion of older deposits. Mega-ripples not associated with the sand ridges were found in great abundance in the area off the Dutch coast. They were all found to have their steepest slope towards the NNE. It is suggested that sand is transported towards the NNE in this area and that the fine fraction accumulates on the Texel Spur. This Texel Spur was found to be covered with extremely well sorted fine sands, which were completely churned. There is evidence, though weak, that this Texel Spur sand is 10 meters thick.
1968Houbolt, J.J.H.C.47(4)Large enclosure E1
1968Houbolt, J.J.H.C.47(4)Large enclosure E2
A survey of the geohydrological and hydrological investigations in the Netherlands1968Heide, S. van der47(4)In this publication a review is given of the hydrogeological investigations in the Netherlands, After incidental research by private companies for water supply the first systematical studies in hydrogeology have been carried out by the Government Institute for Water Supply, which was founded in 1913. It was also this institute which stimulated the hydrogeological investigations by the Zuyder Zee Works. These developed to one of the most extensive in the Netherlands. Modern methods of investigations were introduced in 1951 with the application of geo-electrical methods to determine the boundary between fresh and salt water in the subsoil. As a result of the success of these methods geo-electrical research was further developed in the Netherlands and is applied now in several cases. Among other modern methods the investigations on C14 and stabile isotopes by Dr. J.C. Vogel have to be mentioned. Extensive new hydrogeological investigations commenced after 1953 as a consequence of the Delta Works in the southwestern part of the Netherlands, Extremely detailed hydrogeological information was obtained by these investigations. On the other hand hydrogeological research was undertaken, mainly after the war, in connection with agricultural problems. These are now dealt with by the Institute of Land and Water Management Research in Wageningen. Studies on ground water in the coal mines in South Limburg have been made and hydrogeological mapping of South and Central Limburg has been carried out by the Geological Bureau in Heerlen. Meanwhile a new institute has been founded with the special task of making hydrogeological maps of the Netherlands. This institute, Dienst Grondwaterverkenning TNO (Ground-Water Survey), includes both the TNO Organization for Geo-electrical Research and the TNO Archives of Ground-Water Levels.
Planctonic foraminifera from the Seroe Mainsji formation of Curacao1968Hermes, J.J.47(4)Planldonic Foraminifera from the Seroe Mainsjie Formation of Curacao cannot be fitted with certainty into one of the biostratigraphic zones recognized by Bolli in Trinidad, although there is no doubt that the fauna is restricted to the upper part of the Middle Eocene.
Post glacial sea-level rise in the Christchurch metropolitan area, New Zealand1968Suggate, R.P.47(4)Radiocarbon-dated samples are discussed in relation to the Iocal stratigraphic sequence, which records post-glacial transgression of the sea followed by regression during progradation of the shoreline. They indicate that sea level apparently rose from -17 m (-58 ft) 8,000 years ago and was still rising when it reached its present level about 5,000 years ago; less certainly the sea was at about -22 m (-73 ft) 9,400 years ago. A sea level 5,000 years ago substantially below that of the present day has been commonly advocated in The Netherlands and elsewhere, but a single post-glacial sea-level curve may not be applicable universally.
De invloed van Mg++-ionen op de precipitatie van calcium carbonaat.1968Groot, K. de47(4)
On the stage1968Hinte, J.E. van47(5)The fundamental chronostratigraphic unit is the Stage. Each Stage has its own standard, a type section or stratotype. It is irrelevant whether these sections are “complete” and whether successive stratotypes overlap or not. The stratotypes merely form “reference points” in the ideal chronostratigraphic scale. ln the future chronostratigraphic units will be defined as the rocks formed during the years a - b B.C.. Once the age is measured for beds of a known relative age, the traditional time-scale has done its service, Until then the definition of Stage boundaries mostly will be biostratigraphic and therefore cannot be but subjective and susceptible to changes with evolving paleontologic knowledge and concepts; rigid definitions lead only to fruitless discussions.
Phase contrast applied in the microscopic study of mineral particles in saprolites1968Riezebos, P.A.47(5)Knowledge of the mineralogical composition of silt fractions in weathering material is essential, as it may contribute to understand the relationships between mineral assemblages in sand and clay fractions. The shortcomings of bright field microscopy in the identification of such mineral fragments are discussed. The principles of phase contrast are briefly reviewed, as the application of phase contrast accessories, combined with the use of dispersion staining and variable monochromatic light, considerably facilitates the optical identification of these small mineral particles. A further adventage is that mineralogical information from both sand and silt fractions is obtained in the same way, so that alteration of mineral properties and other features are similarly observed and evaluated with decreasing grain sizes, The results of some investigated samples are presented and the data indicate that the mineral constituents produced by alteration and already present in the sand fractions, increase with decreasing silt sizes and that these alteration products are of detrital nature. It is concluded that in order to characterize and to understand the weathering sequence, a mineralogical analysis of sand and silt fractions is needed.
Spilite-Keratophyres et ophiolites influence de la traversee dún socle sialique sur le magmatisme initial.1968Rocci, G.; Juteau, T.47(5)After giving the definition of the initial magmatism, the authors insist on the typical petrographic associations without tackling the so much debated problem of spilitisation. The petrographic range of products given off during the initial magmatism goes from ultrabasic rocks to hypersiliceous acid keratophyres and includes plutonic rocks as well as true lavas. In so big a range it is difficult to know what kind of associations fits to reality. The American geologists for instance, represented by Turner and Verhoogen (1960) introduce a definite distinction between the spilite-keratophyre serie and the peridotite-serpentinegabbro association, considering the fact that the setting of these two groups appear independent. On the other hand the alpine geologists as their spokesman Vuagnat (1963) remarks, after precise field work observations, consider that the ultrabasicgabbro-diabase group cannot be dissociated and constitutes the ophiolitic suite. Therefore the authors of the present work wonder whether; 1) There are really two distinct associations, a basic and acid one i.e. spilite - keratophyre, the other one being ultrabasic and basic i.e, ultrabasites- gabbros-diabases. 2) And if so are the two associations really compatible in the same geosyncline? To answer these two questions two types of observations are made: one concerning the initial volcanism in the northern limb of the hercynian orogen, the other the geosynclinals magmatism in the alpine ranges. A brief comparison of the characteristics of these two types of phenomena leads to the following conclusion: the ultrabasic rocks are widespread in the alpine orogen but are very uncommon in the hercynian one, meanwhile the volcanic acid rocks appear in important masses only in the hercynian range. Consequently the answer to the preceding questions is possible. In fact there are two types of associations of initial volcanism: the first one, basic and acid, essentially effusive, is the spilite-keratophere association; the other one basic and ultrabasic volcano-plutonic includes the ophiolltic alpine type series.
Some results of profile drilling along the railroad between Onverwacht and Zanderij, Surinam1968Levelt, T.W.M.; Quakernaat, J.47(5)The mineralogical composition of clay fractions in samples of a series of borings between Onverwacht and Zanderij admits a subdivision of the sediments south of the lowland bauxite excavations near Onverwacht, Surinam. Layers with kaolinite, an abundance of illite, and with or without montmorillonite are Lelydorp and Demarara sediments. Deeper layers dominant in kaolinite, with traces to moderate amounts of illite, and sometimes montmorillonite seem to be Para sediments. These beds are deposited over sediments with kaolinite clays belonging to the Onverwacht/Coesewijne series. Where borings reach the weathered bedrock the clay is mostly pure, well crystallized kaolinite. A cross section of the zones of equal clay composition show a sedimentation pattern of layers with incised and refilled gullies. A correlation with the stratigraphy in the coastal plain is given.
The occurrence of halloysite and gibbsite in peneplain deposits of the Belgian Condroz1968Buurman, P.; Plas, L. van der47(5)In sands of the Onx and Om formations on the Belgian Condroz Peneplain both hydrated halloysite and dehydrated halloysite have beenlound in sandpits near Louveigné and Florzé. The occurrence of Florzé is accompanied with gibbsite. X-ray diffraction patterns, electronmicrographs, DTA, TGA, scanning calorimetrical analyses and chemical analyses have been made of both samples and are reported. The material may have derived from the type locality of halloysite discovered near Angleur and described in detail by Berthier. Another possible origin is reIated with the climatological history of the early Ardennes peneplain.
Rb-Sr age determinations of some gneisses and granites of the Aston-Hospitalet Massif (Pyremees)1968Jäger, E.; Zwart, H.J.47(5)A number of radiometric Rb/Sr age determinations on muscovites, biotites and whole rock samples from various gneisses and granites of the Aston-Hospitalet massif have been executed. All apparent muscovite ages fall in the range of 255-274 m.y. dating the end of the Hercynian metamorphism. The biotites of the Aston massif give distinctly younger ages, as young as 113 m.y. This is probably due to a period of heating during a metamorphic episode in Mesozoic times. Total rock analyses were performed on eight granites and gneisses. Three of these analyses define an isochron of 475 m.y.; the other five scatter near a straight line corresponding to 300 m.y. Geological observations and Rb-Sr results suggest that these rocks were formed 475 m.y. ago and were remobilized during Hercynian metamorphism 300 m.y. ago. Because of the low initial Sr87/Sr86 combined with extremely high Rb/Sr-ratios, a formation in Precambrian time can be excluded. The high Rb/Sr-ratios point to magmatic and not sedimentary origin. we therefore explain these rocks as Ordovician granites which were metamorphosed during the Hercynian orogeny.
Ages of Malayan granites1968Snelling, N.J.; Bignell, J.D.; Harding, R.R.47(5)The results of Rb:Sr whole rock age determinations on Malayan granites are summarised. They indicate intrusion during the Upper Carboniferous, Triassic, and Upper Cretaceous. The Triassic granites appear to have been intruded during two episodes at circa 230 m.y, and 200 m,y. Most K:Ar ages on micas from the various granites show evidence of having been disturbed by both younger intrusions and other tectonic phenomena, and the simple assumption that K:Ar ages date the intrusion of the host granite is not necessarily valid.
Introduction Instrumental Analysis1968Roorda, H.J.; Eisma, E.47(6)
Instrumental methods in the chemical analysis of minerals1968Dijkstra, G.47(6)
The application of neutron activation analysis in geochemistry1968Das, H.A.; Sijperda, W.S.47(6)ln geochemical work neutron activation analysis is rapidly gaining upon "classical” techniques such as wet analysis and emission spectrography. The main reason is that activation analysis permits the determination of both major and trace elements; it is a convenient method for the simultaneous determination of a large number of elements in small samples. Moreover, the method is very sensitive for most elements, The present paper deals with neutron activation analysis of rock samples, as performed at the Reactor Centrum Nederland, Petten (NH). The principles of activation analysis are discussed. Then, the determination of silicon, aluminium, iron, potassium, sodium, manganese, scandium, chromium, cobalt, rubidium and cesium is described in more detail, Results, obtained for rock standard G-2, are given.
A new automatic sample changer for the Philips X-ray difractometer PW 10501968Porrenga, D.H.; Versmissen, J.L.47(6)
Aspects of automation in X-ray spectrometry1968Porrenga, D.H.; Versmissen, J.L.47(6)In X-ray spectrometry, full or partial automation of the sample preparation, intensity measurement and data processing has both advantages and drawbacks. Special attention is paid to a new automatic sample changer, which has been made at the Koninklijke/Shell Exploratie en Produktie Laboratorium at Rijswijk as an accessory to a Philips vacuum X-ray spectrometer.
The TPD electron probe X-ray micro analyzer1968Fontijn, L.A.; Bok, A.B.; Kornet, J.G.47(6)The article describes an electron probe X-ray micro-analyzer specially designed for mineralogical investigations and constructed for the Department of Mining Engineering of the Technological University, Delft. A miniature magnetic lens is used in the electron optics making it possible to employ a standard Leitz polarization microscope. The specimen can be rotated around the microscope axis and translated in two orthogonal directions.
Reflectance measurements on coal1968Vries, H.A.W. de; Bokhoven, C.47(6)After giving a description of the reflectance-measuring equipment, the authors discuss the relation between degree of coalification (rank) and reflectance. Coal appears to become ever more anisotropic with increasing rank. The anisotropy observed in coal is reminiscent of the optical behavior of a negative mono-axial crystal. The respective merits of reflectance measurements in polarized and non-polarized light are compared; in this connection attention is given to the accuracy of the rank analysis. Further, a method of approximation is indicated for calculating the reflectance in non-polarized light from the reflectances measured parallel to the ordinary and extra-ordinary rays. In conclusion, the optical behaviour is correlated with the coal structure.
Microradiography and X-ray microscopy in geology1968Jongebloed, W.L.; Porrenga, D.H.47(6)Photographs have been made of a specimen of Operculina with an X-ray projection microscope, a light microscope and by means of microradiography. Comparison of the pictures obtained shows that, if original unsectioned specimens are examined, the two X-ray methods are superior to the lightmicroscope technique as regards both depth of focus and penetration power, These methods are moreover non-destructive and time saving. Results obtained also show that for the rapid and routine investigation of microfossils or for detailed study, the microradiography and X-ray microscopy methods are, respectively, equal or superior to the light-microscope technique,
An electron luminescence microscope1968Poole, J.B. le; Bok, A.B.; Boogerd, W.J.47(6)
Some aspects of a geochemical investigation in an area with low anomaly contrast in S. Limburg (Netherlands)1968Dijkstra, S.; Bot, A.C.W.C.47(6)The present paper deals with a number of aspects of different disciplines relevant to a geochemical investigation which was carried out in the southern part of the Dutch province of Limburg, in an area just north of a former Belgian lead-zinc mining district. Some information on the local geography and geology is briefly summarized, and the structural and stratigraphical controls of ore localization at depth are outlined. From the geochemical point of view the area showed several complex features regarding soil formation and lithology. Metal contamination by human activities constituted an additional problem, Soils and stream sediments displayed low lead and zinc contrast, and metal determinations of high precision were therefore required. Under these conditions dithizone field methods proved to be unsatisfactory, whereas good results were obtained with analytical methods based on atomic-absorption spectrophotometry. The laboratory procedures, which satisfied the particular precision requirements, are described and their applicability for general use in various types of geochemical exploration surveys is discussed. A new statistical method for the grouping of spatially related data is introduced, with the aid of this method geochemical contour maps were drawn and significant differences between a number of broad geochemical patterns could be established.
Quantitative analysis of the available alumina content by (D.T.A.) in bauxite from "Onverdracht", Surinam1968Veen, A.H. van der47(6)A linear relation is found between the available alumina content of bauxites from the mine Onverdacht in Suriname and the gibbsite-peak area as determined by d.t.a. (differential thermal analysis). Available alumina is an economic value, which can be determined by means of bomb digestion and subsequent filtration and titration procedures. These procedures are described in detail. The quantitative d.t.a. method, the apparatus applied and the procedures used, are also described and discussed in detail, Special attention is paid to reproducibility of the d.t.a. and to the systematic operator's errors in order to eliminate such errors as far as possible.
Gas chromatography its principles and applications in organic geochemistry1968Schenck, P.A.47(6)This article is a short introduction to the theoretical and practical aspects of gas chromatography. Several applications in - mainly organic - geochemistry are presented. References are given to general and more specialised literature.
Mass spectrometry and some of its applications in organic geochemstry1968Engelhardt, E.D.47(6)
Report on the second international summer school on quantitative methods in reflected-light microscopy1968Uytenbogaardt, W.47(6)A review is given of the organisation of the Second lnternational Summer School on Quantitative Methods in Reflected-Light Microscopy, held in Bensheim (near Frankfurt), Western Germany, 28 August - 2 September, 1967. The lectures given at this Summer School are mentioned and summarized.
Van de voorzitter aan de leden1968Krol, G.L.47(6)
Naar een genootschap - nieuwe stijl?1968Dijkstra, S.; Weeda, J.; Hols, A.; Tobi, A.C.; Visser, W.A.; Weehuizen, J.M.47(6)
Van de voorzitter aan de leden1969Krol, G.L.48(1)
The paths of grain through wave-like bed forms1969Allen, J.R.L.48(1)From a knowledge of the topography of skin-frictionlines, the paths of transported grains relative to the ground and to bed features are presented for different kinds of wave-Iike bed form encountered in aqueous flows. In the case of a sinusbed (antidunes), the height of the forms and their propagation velocity can be used without correction to measure the rate of downstream transport of sediment involved in the movement of the waves. The flow over a ripple or dune bed is separated' however, and within the forms there occurs a sediment stream moving backward relative to the external flow direction. The rate of downstream transport of sediment involved in movement of the waves is in these cases a net rate depending on the ratio of the thickness of the forward-moving and backwardmoving sediment streams. Thus estimates of bedload transport rate based on the full heights of ripples or dunes can be in substantial error.
Analysis of large scale superposed folding in a migmatite terrain1969Naha, K.; Mukherji, P.48(1)In the "hook syncline" of central Rajasthan, India, the large metasedimentary bands of early Precambrian age, considered to form synclinal cores in the older basement gneisses, represent extensively migmatized palaeosomes. The curious, hook-shaped double closures in the map pattern of these palaeosomes are due to a superposition of tight upright folds with NS-striking axial planes on isoclinal reclined folds plunging westward, a feature duplicated in numerous examples in hand specimen and outcrop. The later folds, which vary in style from open in the southeast to isoclinal in the northwest, have caused a wide scattering in the orientation of the axes and axial planes of the first set of folds. Although the later folds always trend NS, they range in plunge from subhorizontal to vertical, depending on their location in the limbs and hinges of the early folds. Flexure modified by flattening and flow seems to have been the dominant mechanism in the evolution of the folds. Migmatization, which has transgressed the stratigraphic levels, is broadly synkinematic with the first deformation. The style and orientation of the folds of the two systems are mutually incompatible in any single deformation plan. The increase in the intensity of the second deformation westward near the contact of the younger Precambrian (Proterozoic) Delhi System of rocks suggests that it is connected with the Delhi orogeny, whereas the first folding on an EW trend is linked with an earlier orogeny, hitherto unrecognized in Rajasthan.
Late Albian foraminifera from the subbetic of Southern Spain1969Hermes, J.J.48(1)A fauna of planktonic Foraminifera from the Late Albian of southern Spain is described. The genus Ticinella is discussed in some detail. The species of Hedbergella from the Albian and Cenomanian are reviewed
Submarine canyon and fan deposits in the Upper Cretaceous of the South-Central Pyrenees, Spain1969Hoorn, B. van48(1)This preliminary study shows the existence of a submarine canyon during Upper Cretaceous time in the South-Central Pyrenees. Deposits filling up this canyon are mainly an alternation of thick limestone breccias and calcareous quartz sandstone layers in the western part of the area, grading into an alternation of limestone breccias, turbidites and blue marls in the east. A western location of the source area of breccia components is demonstrated by their stratigraphic record and measured current directions. After a short transport on a relatively steep slope in a submarine canyon, material was deposited in the canyon mouth building up submarine fans.
Remarks on the age of emplacement of the Betic of Málaga in the Sierra Espuña, Spain1969Hermes, J.J.; Kuhry, B.48(1)Observations in the Sierra Espuña region disprove paquet’s assumption (1966a, 1966b, 1967, 1968) of the transgressive character of his "Auversian conglomerates" and thus of the emplacement of the upper tectonic units of the Betic of Málaga before the Auversian and after the Lutetian.
Strontium-isotopen en Rb-Sr chronometrie1969Priem, H.N.A.48(1)
De toekomstige drinkwatervoorziening van Nederland1969Huisman, L.48(1)
Evenwichten tussen calciumcarbonaat en phosphaationen in zoet water.1969Golterman, H.L.; Hogendijk, C.J.48(1)
Karstverschijnselen1969Heege, J.P. ter48(1)
Reakties op "naar een genootschap - nieuwe stijl?"196948(2)
In memoriam Prof. Dr. J.P. Bakker1969Pannekoek, A.J.48(2)
Introduction and summary of the stratigraphical and sedimentological results of boring alliance-28 in the coastal plain of Surinam (Dutch Guiana)1969Voorthuysen, J.H. van48(2)
Boron content of core samples from alliance-28, Surinam, as an indicator of paleosalinity1969Porrenga, D.H.48(2)The boron content of the clay fraction of 66 samples from the 338-m deep core hole Alliance-28 in Northern Surinam, indicates a marine palaeosalinity in the Paleocene-Eocene interval at about 295, 240 and 223 m depth, in the Pleistocene interval at about 80 m depth and also in the larger part of the Holocene interval. It furthermore suggests deposition in (almost) fresh water in the upper and lower part of the Paleocene-Eocene interval and in the Pliocene interval. Brackish water is indicated for some parts of the Paleocene-Eocene and the larger part of the Pleistocene intervals. The boron content is relatively high (60-140) ppm) in the clay fraction of calcareous and/or glauconitic sediments, markedly less (30-60 ppm) in sediments intercalated with brown coal and generally lowest (1040 ppm) in white kaolin layers.
The clay minerals from the boring Alliance-28, Surinam1969Hartman, P.48(2)The clay mineralogical composition of about 75 samples is reported. Kaolinite and anatase are always present, and in some layers these are the only minerals in the clay fraction. In other layers kaolinite is associated with montmorillonite and/or disordered illite-montmorillonite mixed-layer minerals. In two layers illite is found, but always associated with the other clay minerals. In some samples traces of vermiculite and pyrite occur.
Palynology of the Alliance well, Surinam1969Wijmstra, T.A.48(2)In this article the palynology of the Alliance well is discussed. From the pollenzones observed in this well the presence of Upper Cretaceous, Paleocene, Eocene, Miocene and Plio-Pleistocene strata could be proved. Also a correlation with marine micropaleontological horizons has been established.
1969Wijmstra, T.A.48(2)Large Enclosures
Holocene and paleocene foraminifera of boring Alliance-28 in Surinam (Dutch Guiana)1969Voorthuysen, J.H. van48(2)This paper presents a description of the Foraminifera of the marine part of the geological column of the coastal plain of Dutch Guiana (Surinam) derived from the cored waterwell Alliance 28 to a depth of 337.50 m.
Preliminary note on the ostracod faunas of the boring Alliance-28 in Surinam (Dutch Guiana)1969Noordermeer, E.J.; Wagner, C.W.48(2)Large Enclosures
Preliminary note on the ostracod faunas of the boring Alliance-28 in Surinam (Dutch Guiana)1969Noordermeer, E.J.; Wagner, C.W.48(2)
Paleocene bryozoa from a boring in Surinam1969Lagaaij, R.48(2)Two species of Bryozoa, identified as belonging to the genera Nellia and "Vincularia", occur in some quantity in the Paleocene interval in the boring Alliance-28, drilled in the coastal plain of Surinam (Dutch Guiana). Both the Nellia and the "Vincularia" occur in assemblages virtually consisting of one single species. Recent assemblages in which Nettia makes up 80-100% of the total count indicate shallow inner-neritic (2-10 fathoms) conditions, coupled with slightly reduced salinities (<33‰). A similar environment is inferred for the Paleocene Nellia assemblage in the boring.
Mollusca from boring "Allicance-28"in Surinam (Dutch Guiana)1969Regteren Altena, C.O. van48(2)Molluscan remains have been studied from depths of 12.25, 15.00 and, 16.25 m and from sixteen levels from depths between 258.85 and 311.00 m. The fauna of the first series of samples agrees with the Recent fauna of the Surinam coast and seems to have lived at moderate depth, say about ten fathoms, off the coast in and on a muddy clay bottom with occasional sand bars, but without hard rock. The fauna of the second series is supposed to be of Palaeocene age on the base of the associated Foraminifera. The molluscan remains consist mainly of fragments and young specimens, for the greater part of oysters. These remains are too poor for specific identification. About ten families or genera can be recognised, among which Vulselta is remarkable. This genus, which is rare in the Tertiaries of the New World, is represented by several hinge fragments.
A microproblematicum from the Paleocene of Surinam1969Hughes Clarke, M.W.48(2)A problematic single-chambered microfossil is described from the Paleocene of boring Alliance 28 in Surinam (Dutch Guiana). Its possible affinities are briefly discussed.
Geomorphology and sediments of Western Surinam shelf; a preliminary note1969Nota, D.J.G.48(2)
Geological and geophysical evidence for a rift valley in the Guiana Shield1969McConnell, R.B.; Masson Smith, D.; Berrange, J.P.48(2)Geological and geophysical evidence points to the existence in the Guiana Shield between latitudes 3°N and 4°N of a steep-walled graben structure which is filled with a thick packet of sediments of which the uppermost is the Takutu Formation showing rare outcrops beneath a blanket of laterite and Quaternary alluvium. The Takutu Formation has been dated on palynological evidence (van der Hamm en and Burger, 1966) as Jurassic to Cretaceous. A gravity reconnaissance was carried out over the western portion of the structure and revealed anomalies which indicate a depth to basement of several km, The strike of the geological structure appears to be ENE-WSW over 160 km, with a width of 50 km, and it is suggested that it is in the nature of a rift valley: it has been considered to constitute a major structural break which divides the folded Precambrian formations of Guyana into northern and southern geological provinces.
The geochronology of Guyana1969Snelling, N.J.; McConnell, R.B.48(2)The Precambrian rocks of Guyana occur in two geological provinces separated by a structural break followed in part by an infilled rift valley which traverses the country to the immediate south of latitude 4°N. North of this structure the folded and more or less metamorphosed sedimentary and volcanic rocks of the Barama-Mazaruni Assemblage and the gneissose granitic rocks of the Bartica Assemblage are intruded by members of the Younger Granite Group, and all are overlain with marked unconformity by the tabular, continental deposits of the Roraima Formation. Both the Roraima Formation and the pre-Roraima rocks are cut by dolerite dykes and sills which constitute the Younger Basic Intrusive Group, including the Roraima Intrusive Suite and a minor dyke suite. Age determinations indicate a younger limit to the post-Barama-Mazaruni-Bartica diastrophism of c.2000 m.y. This diastrophism is now termed the Akawaian episode and is believed to correspond closely in time to the emplacement of most of the Younger Granites. One member of the Mazaruni Group is possibly older than c.2500 m.y. A younger limit to the Roraima Formation of c.1700 m.y. is set by K-Ar and Rb-Sr age determinations on the dolerites of the Roraima Intrusive Suite and on micas of a contact hornfels in the Roraima Formation. In the southern geological province the major rock unit is the South Savanna Granite which intrudes high-grade gneisses (granulite facies) of the Kanuku Group and metasediments of the Marudi Group. A uranium-lead determination, though affected by uranium leaching, sets a maximum limit to the age of this granite of 2075 m.y., and Rb-Sr determinations indicate emplacement at c.1850 m.y. The granite shows evidence of dynamic metamorphism, and K-Ar determinations on micas suggest an age of c.1200 m.y. for this metamorphism. The Kanuku gneisses and South Savanna granites are cut by dolerite dykes, one of which has been dated at 450 m.y.
Pollen analysis of two sections in the young coastal plain of Surinam1969Roeleveld, W.48(2)Pollen diagrams have been made of two sections in the young coastal plain of Surinam (S. America). According to C 14 dates the clayey and peaty sediments have an early Holocene age. The pollen diagrams clearly show the changes of the vegetation caused by the postglacial ingression of the sea.
Rede, uitgesproken door de voorzitter van het KNGMG, bij de aanbieding van de van Waterschoot van der Gracht penning aan Ir. C.E.P.M. Raedts op 15 maart 1969196948(3)
Rede, uitgesproken door de voorzitter van het KNGMG, bij de aanbieding van de van Waterschoot van der Gracht penning aan Prof. Dr. L.U. de Sitter op 15 maart 1969196948(3)
Afscheidscollege Prof. Dr. F.J. Faber196948(3)
Orogenic evolution of the Betic Zone (Betic Cordilleras, Spain), with emphasis on the nappe structures1969Egeler, C.G.; Simon, O.J.48(3)The structure in the southeastern section of the Betic Zone reflects a highly complex evolution during the Alpine cycle, including several orogenic phases of different character. At least two major phases of overthrusting appear to have played a role in the formation of the nappe structures. A number of problems are briefly commented upon, including the direction and the age of the nappe movements and the amount of shortening.
Orogenic evolution of the Betic Zone (Betic Cordilleras, Spain), with emphasis on the nappe structures1969Egeler, C.G.; Simon, O.J.48(3)Large Enclosure 1
Orogenic evolution of the Betic Zone (Betic Cordilleras, Spain), with emphasis on the nappe structures1969Egeler, C.G.; Simon, O.J.48(3)Large Enclosure 2
Preface INQUA Subcommission on the Study of the Holocene and that on Baltic and North Sea
Shorelines, held in the Netherlands in October 1968
1969Hageman, B.P.48(3)
The cause of the holocene climate change1969Kukla, J.48(3)The worldwide repeated changes of climate through the whole Quaternary era make it clear that the recent general weather conditions will not last forever, but will be substituted by a severe Glacial stage, similar to those recorded in the close geological past. It is highly important for humanity to know, at what time the climate deterioration is to be expected, which processes are ruling it and how to fight the incoming cooling trend. The first results of a new method are described, based on the calculation of the main part of the past earth's heat budget. The heat reaction of the snowline is detected as being the principal key controlling the global climate change and as strongly amplifying any slight thermal impulse of interplanetary or terrestrial origin. The perturbations of the earth's orbital elements are found to be responsible for the general long-time climatic changes including the start and the end of the Holocene interglacial. The convincing proof for this statement lies in the isotope dated geological evidence of the past 250,000 years. We are now able to date astronomically the various gross past climatic trends with a relatively high accuracy. The short-range oscillations of climate observed during Holocene, may partly reflect the short-time movements of earth's rotational axis and/or the changes of the solar constant, both up to now very poorly investigated. Strong suspection, however, exists that the Little Ice Ages of the Late Holocene and the global warming which started at around A.D. 1890 are both the results of mans activity. Further investigation in this branch is urgently needed, because the pronounced weather deterioration is expected to come in the close future.
An outline of the geological history of the coastal dunes in the Western Netherlands1969Jelgersma, S.; Regteren Altena, J.F. van48(3)
The marine holocene of sylt - discussion of the age and facies1969Hoffmann, D.48(3)Investigation of the marsh area of Sylt during 1965-66-67 yielded new data regarding the development of Sylt during the Holocene. Three transgressions of the sea were established. The deposits of the first belong to the Calais (according to Brand et al. 1966) and the others to the Dunkirk. The ages of the transgressions were determined by means of 14C-analysis and cultural layers. South of Westerland, the finegrained facies of the second transgression indicates that the area was well protected by the “Geestkerne" and the southern beach-barrier of the island.
on the Würm - Flandrian boundary in Deep-sea cores1969Olausson, E.48(3)Due to the present drainage pattern the North Atlantic receives much more weathered products than the other oceans do. Dissolutions and oxidations at the bottom of the North Atlantic seem to change in time, being climatologically controlled. The dissolution of carbonates in North Atlantic has been intensified during ice ages mainly in the zone of Polar Bottom Water. During the Main (Upper) Würm the Arctic Ocean was not ice covered because of the absence of a salinity discontinuity (halocline). It is believed that an intense formation of bottom water occurred there and that this water then flushed the North Atlantic bottom and caused the increased dissolution of carbonates. At the transition Alleröd/Younger Dryas (Würm/Flandrian boundary) the Arctic Ocean was covered by a pack-ice. The developed halocline stopped the sink water formation. Then the outflow of cool bottom water to the Norwegian Sea dropped suddenly. The lack of this bottom water caused an increased carbonate deposition in the North Atlantic approximately 11,000 B.P., and somewhat later on, a decrease of it occurred in the Indian and Pacific Oceans (see fig. 1). The isotopic paleotemperature method has been found invalid. The percentages of warmwater-indicating foraminifera suggest that the North Atlantic gradually became warmer from the Alleröd up to the climatic optimum about 6000 B.P. The precipitation in the arid lands around the Gulf of Aden during the late Würm and Flandrian are given in Fig. 6. The highest precipitation during aforementioned times occurred during the Atlantic subage and the lowest one during the Preboreal subage. It is suggested that the Red Sea was dry during maximum of the Main (Upper) Würm Ice age. A marked change in the vertical circulation happened about 8000 B.P. The Eastern Mediterranean and the Cariaco Trench changed into a (quasi)stagnant phase approximately during or at the end of the Alleröd subage. The climatic deterioration during the younger Dryas stadial is explained as caused by the albedo change which occurred when the Arctic Ocean went into the pack ice phase. The duration of this stadial is about 600 yrs. Such a short interval is hard to trace in abyssal cores. The last large change in deepsea cores has probably happened at the end of the Alleröd subage. These two points suggest that the upper boundary of the Würm age is to be placed at the Earlier Dryas - Alleröd boundary. The present age is here called Flandrian since Holocene is a term of higher rank (epoch). I also suggest that Pleistocene should be considered as the only epoch in the euaternary period- "Holocene" could be discarded.
The pleistocene-holocene boundary: an evaluation of the various criteria used for determining it on a provincial basis, and suggestions for establishing it world-wide1969Morrison, R.B.48(4)
Development of the western part of the Netherlands during the holocene1969Hageman, B.P.48(4)
Eustatic and climatic changes during the last 15,000 years1969Mörner, N.A.48(4)This is a short description of the results concerning shorelevel displacement, isostasy, eustasy and climatic changes obtained from a comprehensive investigation of the Late Quaternary history of the Kattegatt Sea and the Swedish West Coast (Southern Scandinavia). This investigation has been described in its entirety in a thorough monography (Mörner 1969), to which I refer for further information.
Zur Pleistozän/Holozän-grenze im südlichen peribaltischen raum1969Kliewe, H.48(4)
Internal structure of some tidal mega-ripples on a shoal in the Westerschelde estuary, the Netherlands report of a preliminary investigation1969Boersma, J.R.48(4)Ebb mega-ripples on a sandy shoal in the Westerschelde estuary (SW-Netherlands) were studied in crossection. The internal structure is dominated by large scale ebb-directed cross-stratification of a particular type showing flood induced erosional and/or depositional modifications. The characteristics betraying the tidal origin of the crossstratified structure are: 1.. Erosional unconformities (diastems) between the successive cross-stratal bundles that build one large scale set. 2. Regular alternations between such bundles and conformably inclined solitary trains of small scale sets containing upslope directed cross-strata. 3. The isolated occurrence of a ± 1 dm thick coset of small scale cross-strata conformably intercalated between two of the above mentioned bundles. 4. (Sub)horizontal cosets of small scale cross-stratification erosively separating vertically successive large scale ebbsets. The above mentioned features confirm the subordinate and rather erosional activity of the flood currents as compared with that of the ebb.
KNGMG notulen van de 57e Gewone Algemene Vergadering 1969196948(4)
VERHANDELINGEN, DEEL 26, I969, rectificatie pagina 157196948(5)
Ter herdenking Dr. Ir. Th. Groothoff1969Vooys, G.J. de48(5)
The tin industry1969Jones, M.P.48(5)
The quarternary geology of the Dutch part of the North Sea, north of the Frisian Isles1969Oele, E.48(5)A geological map of the Dutch part of the North Sea, north of 53°20' lat. is presented. Fluvioglacial clays of the Elsterian glaciation are presumed to underlie the younger deposits. During the Saalian glaciation the clay was partly eroded by glaciers, which led to the formation of the central deep southeast of the Dogger Bank, the bank itself being an erosion rest. At the same time boulder clay of Scandinavian origin was deposited. Deposits of the Holsteinian and Eemian interglacials have not been found. Owing to the rapid rise of the sea level supply and sedimentation could not keep up with it. During the Early- and Late-Weichselian fluvial clays were deposited, while coversands were laid down during Weichselian Pleniglacial times. The surface of the fluvioglacial clay in the central deep remained uncovered owing to strong winds. The Holocene sequence starts with a basal peat bed, on top of which fresh-water clay settled. The transgreding sea led to the formation first of brackish to marine clayey, later of sandy deposits. (Elbow deposits). During the Atlantic and Subboreal no sediments were deposited. In the present Subatlantic a reworking and deposition of the material present led to the formation of the young seasand bed.
The quarternary geology of the Dutch part of the North Sea, north of the Frisian Isles1969Oele, E.48(5)Large Enclosure
Deformation of an alpine ultramafic association in Darvel Bay, East Sabah, Malaysia1969Hutchison, C.S.; Dhonau, T.J.48(5)The island-arc system of the Philippines, which includes the well-known Zambales alpine complex, continues westwards along Palawan island and along the Sulu archipelago into North Borneo. Within this arc, there is a characteristic association of ultramafic rocks, banded amphibolites of gabbroic composition, and a younger flysch sequence characterised by abundant spilites. In the Darvel Bay area of east Sabah (North Borneo), the ultramafic rocks are shown to be concordantly interfoliated with the banded amphibolites. The folding, which is predominantly along an east-west axial direction, has been accompanied by dynamothermal metamorphism characteristically to almandine-amphibolite facies. An increase in metamorphism to hornblende-granulite facies occurs in a "thermal aureole" of the syntectonic ultramafic body in central Darvel Bay. The island-arc system has been subjected to several periods of deformation, the youngest of which was accompanied by greenschist facies metamorphism, which has affected not only the ultramafic-metabasite association, but also the overlying flysch sequence and has converted many of the spilites to amphibolites. Structural data indicate that ultramafic intrusions accompanied both the older and the younger periods of deformation. Subsequent intense faulting has further obscured the earlier tectonic history of the ultramafic association.
Palynologie en classificatie van Perm en Trias in West-Europa1969Visscher, H.48(5)
Palynostratigrafische problematiek van de "Lettenkohle" in Zuid-Frankrijk1969Gradstein, F.M.48(5)
Surface protection around abandonned mine shafts1969Schilp, R.48(5)
Investigations in the Västervik area, southeastern Sweden - 1. Structural geology and genesis of the "younger" granites1969Westra, L.; Elbers, F.J.; Sijperda, W.S.48(6)A geological map, short description and general petrological discussion is given of a small part of Svecofennian in SE-Sweden. The problems concern a relatively small sedimentary complex and surrounding granite gneisses, hybide diorites, migmatites and associated "younger" granites. Structural analysis has revealed that deformation has taken place in at least two phases. The first phase is characterized by isoclinal folding of the bedding plane with horizontal axial plane and generation of axial plane schistosity of newly formed mica. The second and dominant deformation phase is characterized by parallel, often plastic, folding with vertical axial plane. The metamorphism linked with this second phase is characterized by the crystallization of andalusite and sillimanite in sediments of appropriate composition. Moreover, this deformation is accompanied by extensive migmatization and the intrusion of granite dikes, the so-called "younger" granites, A mushroom-like interference pattern of superposed folds from both phases is extensively discussed. A new geochemical test is applied to establish the depth of intrusion of the "younger" granites. This test is based on the variation of the eutectic composition of a granitic melt at varying pressures, as determined experimentally by von Platen and Höller (1966). The results suggest a rather shallow depth of intrusion, which corresponds to the type of the broadly contemporaneous metamorphism of the associated sediments. Results of the analysis of trace elements of the "younger" granites, especially the low K/Rb-ratio, indicate an anatectic origin of these granites.
Investigations in the Västervik area, southeastern Sweden - 1. Structural geology and genesis of the "younger" granites1969Westra, L.; Elbers, F.J.; Sijperda, W.S.48(6)Large Enclosure
Investigations in the Västervik area, southeastern Sweden - 2. Isotopic age determinations1969Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verschure, R.H.; Verdurmen, E.A.T.48(6)Whole-rocks of three granites and a gneiss from the Västervik area, south-eastern Sweden, have a Rb-Sr age of 1750 ± 50 million years: (late) Svecofennian. Age measurements on three separated biotites disclose the imprints of younger, probably Gothian events, but a discordance exists between the K-Ar and Rb-Sr ages: 1465 ± 30 and 1380 ± 50 million years, respectively. A pegmatite yielded a Rb-Sr whole-rock age of 1425 ± 50 million years.
Mining of wide, flatly dipping reefs at Kamativi tin mines LTD., Rhodesia1969Botman, A.G.48(6)A description is given here of the development of ideas and activities that have-led to the introduction of a new method of mining deep, thick, flatly dipping pegmatite reefs at Kamativi, Rhodesia.
Paleomagnetism of some Late Paleozoic and Triassic rocks from the eastern Lombardic Alps, Italy1969Zijderveld, J.D.A.; Jong, K.A. de48(6)The directions of magnetization of five volcanic units of the Late Paleozoic rock sequence from the Eastern Lombardic Alps, each sampled at one site, display small within unit dispersion and rather large between-unit dispersion. They yield a mean direction of D = 135°, I = -21° (α95 = 20°), which is as divergent from the Late Paleozoic paleomagnetic field in the Alpine Foreland as the directions of contemporaneous rocks in other places in the Southern Alps. The characteristic magnetization direction of the Middle Triassic porphyrite of Valle di Scalve is D=161°, I=-21°. It is remarkably similar to the Late Paleozoic results and rather different from other Triassic paleomagnetic directions from the Southern AIps. Both the Late Paleozoic and the Triassic paleomagnetic directions indicate a counterclockwise rotation of the Southern AIps with respect to the Alpine Foreland (about 50°). There is no clear paleomagnetic evidence of large translational megatectonic movements between the Southern Alps and the Alpine Foreland.
A preliminary report on the stratigraphical position of the Matuyama-Brunhes geomagnetic field reversal in the Quaternary sediments of the Netherlands1969Montfrans, H.M. van; Hospers, J.48(6)Continental sediments of Quaternary age from the Netherlands have been investigated palaeomagnetically. The evidence available at present concerning the stratigraphical position of the Matuyama-Brunhes geomagnetic field reversal (0.70 m.y. ago) places this boundary in or directly above the "Cromerian" interglacial stage. It is known that in the Netherlands the "Cromerian" interglacial stage was preceded by and followed by three glacial stages.
Notulen van de Buitengewone Ledenvergadering oktober 1969196948(6)
Research on ventilation and safety and its application at Dutch state mines1970Maas, W.49(1)Dutch Statemines conducted until 1965 research for underground operations in the Centraal Proefstation. The present paper sketches the image formed on the occurrence of methane in the underground works, its release during mining operations, the method of safe dilution, and the removal in high concentrations. It gives measures taken to prevent ignition possibilities and finally describes how using the results of this research the Inspectorate allowed to increase the methane percentage in the general body of the air from 1.5 to 2 %.
The angle of initial yield of haphazard assemblages of equal spheres in bulk1970Allen, J.R.L.49(1)The maximum slope angle assumed by heaped granular solids is of considerable interest in geology, geomorphology and soil mechanics, as also is the slope stability of such heaps. Representing the solids by equal spheres, we here deduce that the relationship between the maximum slope angle (angle of initial yield) and the concentration of equal spheres arranged haphazardly in bulk in the gravity field is tan Φi= k1C - k2 + A, in which Φi is the angle of initial yield, C is the fractional volume concentration, k1 and k2 are known constants depending on the properties of equal spheres in regular cubical and rhombohedral array, and A is a variable dimensionless coefficient representing frictional, electrostatic and other non-gravitational forces. This relationship is broadly confirmed by experiments using glass beads of two different narrow size ranges, though the experiments are not of a high order and accuracy. It is of interest that a natural sand, well sorted compared with other sands but still showing an approximately 1 : 4 range of sizes, also conforms to the relationship deduced for equal spheres.
De oudste mijnbouw in Nederland1970Engelen, F.H.C.49(1)In 1881 flint-working sites were discovered in the south of the Netherlands, in the neighbourhood of Maastricht near the Belgium border. Specially Belgium archeologists from the university of Liege did field work in this site till 1953. In 1914 the first shaft and a mining gallery were found in the wall of a small ravine. During 1923-1925 Prof. Dr. v. Giffen and Dr. v.d. Sleen were the first archeologists of Dutch origin who did some succesful excavations. In 1964 Prof.Dr. Waterbolk from the Biological Archeological Institute of the Groningen University discovered a couple of shafts more than 140 meters from the ravine. So he proved that a very extended mining-activity had existed in neolithic times. At that time, twelve members of the Netherlands Geological Association planned to continue the excavations by digging a gallery from the first-discovered flintmines up to the new shaftfield. This gallery will have a total length of ± 140 m. At both sides 10 meters of the chalk-rock had to be explored on prehistorical mining activities. The members of the group, working in the week-ends during more than 4 years, made a gallery of 100 meters length already and penetrated into the prehistorical flintmines. They have dug out more than 500 meters of ancient galleries and discovered about 35 shafts. A deep insight has been obtained in the mining-system of the neolithic miners, who used the pillar and room system and made shafts of ± 10 meters deep. More than 7500 flint-picks, used during the work, have been found, some deerhornpicks, charcoal and a human skull. A radio-carbon determination of the charcoal dated the prehistorical mining activities at 3150 (± 60) before Christ. During the more than four years of excavations the working method was modernized. Starting with barrows, changing over to lorries, the group now uses a beltconveyor. Instead of steelpicks, now pneumatic hammers are used and the working-site is lighted by electric lamps. A great deal of work is still to be done by the members of the group before the gallery will be completed over its total length. The working group proved that the neolithic flintmining industry in the Netherlands is of the same rank as that of Spiennes in Belgium and of other well-known neolithic mines in Europe.
Grading of matrix and pebble characteristics in syntectonic pebbly mudstones and associated conglomerates with examples from the carboniferous of Northern Spain1970Loon, A.J. van49(1)Pebbly mudstones are known from many syntectonic sediments. Since particles of clay size can only be deposited in very quiet water, in which pebbles cannot be transported, the occurrence of pebbles and, a clayey matrix proves that such sediments must have been transported by mass movement. If the matrix of the pebble-containing sediment consists of sand grains, the sediment could have been deposited grain after grain. But here too it may have been transported by mass movement, which can sometimes be proved if the matrix grades from sand to silt or even clay size. Three examples from the Upper Carboniferous of the Cantabrian Mountains (N. Spain) are described. Attention has been paid to the characteristics of the pebbles, from which the mechanism of deposition can be reconstructed.
Grading of matrix and pebble characteristics in syntectonic pebbly mudstones and associated conglomerates with examples from the carboniferous of Northern Spain1970Loon, A.J. van49(1)Large Enclosure
Preliminary note on pleistoccene sealevel fluctuation in the southwestern parts of the Netherlands1970Voorthuysen, J.H. van49(1)
Transgressivite de l'eocene suprieur dans les malaguides de la Sierra de Espuña (Cordilleres Betiques, Sud est de l'espagne) mise au point1970Paquet, J.49(1)
Genootschapszaken: AAPG zusterorganisatie197049(1)
Experimental marine suspension currents, competency and capacity1970Kuenen, P.H.; Sengupta, S.49(2)In a circular flume (diameter 4 m) suspension currents were generated with various kinds and concentrations of clay (lutum) and sand. Starting from maximum velocity (230 or 300 cm/sec) samples were drawn off at successively lower velocities at three levels. The amount in suspension coarser than 33 microns was measured and for a number of representative cases grain size analyses of these sands were made. There is an increase in median and amount from the higher to lower levels. At curent velocity of 48 cm/sec particles smaller than 38 microns are not concentrated towards the bottom. At higher velocities there is even concentration upwards in some cases for grains smaller than 150 microns. The results demonstrate that the concepts of competency and capacity are strongly interrelated, the grain size distribution of the load in suspension depending on the original charge placed in the flume. The deposits tended to show log-normal distribution, the steepness of the cumulative curve depending on the composition of the suspension. All grain sizes in suspension were involved in the deposit forming. This was not due to current fluctuations and only partially to entrapment of fines between coarser grains. The coarser the fraction the more is abandoned relatively. For this reason the remaining suspension does show a decreasing median. The lutum greatly increases the carrying power, especially for finer grain sizes, the strongly flocculated Wadden Sea lutum having the greatest influence. The quantitative results are presumably roughly applicable to the lower part of turbidity currents. However, the exchange with higher levels is excluded in the experiments, and the paddles cause increased turbulence. Spiral flow is another drawback. For the deposition of a bed with median size of 200 microns, a velocity of 2 to 3 metres is required, for a median of 1 mm (that is to say a gravelly turbidite) something of the order of 10 m/sec, much depending on the concentration of lutum. At rippling velocity, about 50-60 cm/sec, the median of the deposit is around 80 microns. There appears to be no or only insignificant exchange between deposit and current in so far as concerns the grains that have become immobilized. No flutings or groovings develop during the process of deposition. Even while rippling is going on there is no or only slight local erosion. The climbing ripples of many turbidites with deposition on the stoss-side betoken non-erosion. No indications of the existence of a traction carpet were found or observed, a circumstance that is attributed to the absence of grains larger than those carried all the way in suspension.
Some data on the Holocene deposits in the Mark and Weerijs valleys (prov. Of Noord-Brabant, the Netherlands)1970Riezebos, P.A.; Slotboom, R.T.49(2)Descriptions of cores from Holocene sediments in the Mark and Weerijs valleys (Province of Noord-Brabant, The Netherlands) allow the distinction of two groups of profiles. Those of the first group show humous sand at the top, underlain by peat. The sand may be more clayey at the base. In the present paper, this sand is indicated as a type I deposit. In the second group of profiles the peat contains an intercalated fine-sandy clay layer, indicated as a type II deposit. The thickness of this layer varies strongly, and the over- and underlying peat may be partially or wholly absent. Field observations point to a high-water origin of the type I deposits. Micropaleontological data from deposits of type II appear to indicate deposition in a fresh-water environment. Heavy-mineral data from type I and II deposits suggest a common source of origin. Grain size analyses, however, show a marked difference between the two types. This difference in grain-size distribution is attributed to an enrichment of type I deposits by cover sand. Palynological investigation of four complete cores showed that sediments of type I have been deposited in both valleys since the early Middle Ages. In the Mark valley, the deposition of type II started with the Atlantic and continued at least up to the Subatlantic. The formation of this type of deposit in the Weerijs valley appears to be confined to the Subboreal. The earlier sedimentation in the Mark valley is thought to be due to the post-glacial rise of the phreatic surface and to a deeper level of the Mark valley bottom. The presence of type II sediments of Atlantic and Subboreal age intercalated in peat, suggest that this relative rise of the phreatic surface was stronger during the Atlantic and Subboreal.
Quaternary shore lines of the Sunda land Southeast Asia1970Tjia, H.D.49(2)All frequently occurring positive shore lines and a few of the submerged strand lines of the Sunda Land, i.e. comprising the Sunda Shelf, Malayan Peninsula, eastern rim of Sumatra, South and West Kalimantan (Borneo), can be correlated with the classical examples of Quaternary shore lines of the Mediterranean and elsewhere. The submarine shore lines of the Sunda Land are at depths of -82-90 m, -67 m, -60 m, -50-51 m, -45 m, -36 m, -30-33 m, - 28 m, -18-22m, -13 m, -10 m, and -7 m. Elevated beaches above the present sea level are at +10-12 m, +16-18 m, +30-33 m, and +50 m. Variable sea levels of the past 6,000 years left traces at a few meters below till about 6 meter above the present sea stand. Warping appears to be indicated along the western margin of the Sunda Land where on one side submergence amounting to 30 m and on the other side emergence of 30 m have occurred since the last glaciation.
A reconnaissance of deltaic environment in the Middle Eocene of the south -central Pyrenees, Spain1970Eden, J.G. van49(2)A regressive sequence of Eocene sediments is exposed in an area West of Tremp (South-Central Pyrenees, Spain). The sequence forms part of deposits formed in the Upper Cretaceous-Eocene marginal basin south of the Pyrenees. Insignificant amounts of continental and littoral deposits are preserved on the north coast of this marginal basin. In the studied areas, however, on the eastern margin of the basin, a variety of continental environments is found. Three formations axe distinguished within the Eocene deposits. At the base is the Roda Formation with a regressive marine series of limestone, marl, and sandstone. Partly overlying this formation and partly laterally transitional to it is the Montaña Formation, with continental and littoral deposits. The Santa Liestra Formation, formed after a major regressive phase, is the youngest. The distribution of these formations on the geological map and their main sedimentary facies are presented in figure 1. The Montañana Formation is regarded as a deltaic association. Two major sedimentary environments are distinguished: (1) a flood-plain environment with fluvial sandstones, conglomerates and finer sediments of the inter-distributary lagoons and swamps, and (2) a transitional environment with channel mouth, bay, tidal flat, and deltafront deposits, containing marine fauna. Two types of large-scale cross-bedding, with different origins are compared. One is interpreted as river subdeltaic formations in lagoons, while the other has been formed by lateral deposition in a migrating river channel. Several small sedimentary structures occur, of which "current crescent marks" and "longitudinal furrows-and-ridges" are discussed in some detail. Excellent exposure of the Montañana Formation provided the opportunity for an almost complete paleogeographic interpretation. The paleogeographic pattern of the floodplain is not that of the ideal delta, in which one major stream forms a fan-shaped deposit. Instead there is a concentration of supply from the north and east by several small rivers, caused by the configuration of the upland area.
Jhr. Dr. Ir. P.J.C. de Wijckerslooth de Weerdesteijn (1904-1969)197049(2)
On the genesis and emplacement of the ophiolites in the Oman mountains "Geosyncline"1970Reinhardt, B.M.49(2)
Van de voorzitter aan de leden197049(3)
Rede uitgesproken door de voorziter van het genootschap bij de uitreiking van de van Waterschoot van der Gracht penning aan de Prof. Dr. Ir. R.W. van Bemmelen197049(3)
Ter herdenking Prof. Dr. G.J.A. Grond 1890-19701970Drent, S.49(3)
Lunar rocks and minerals1970Zussman, J.49(3)
The systematic packing of prolate spheroids with reference to concentration and dilatancy1970Allen, J.R.L.49(3)The use of the sphere as the ideal sedimentary particle is criticised and the prolate spheroid (ellipsoid of revolution) is proposed as a more realistic alternative. Equal prolate spheroids identically oriented in space can be packed in six ways analogous to the six packings of equal spheres. The volume concentration of spheroids in systematic packing is identical with the concentration of spheres in the equivalent packing, except in cases of "cubic" packing in which concentration is a function of spheroid orientation and axial ratio. The dilatation angle of assemblages of prolate spheroids is a function of type and orientation of packing and of spheroid orientation relative to the direction of displacement. The maximum angle of initial yield of packings of spheroids is also dependent on type and orientation of packing and on spheroid orientation. The implications of these findings for the steepness and stability of slopes formed on loose granular materials are discussed.
Mikroskopische untersuchungen an gesteinshüttenprodukten und schlacken1970Trojer, F.49(3)
Wodginite from northeastern Brazil1970Burke, E.A.J.; Kieft, C.; Felius, R.O.; Adusumilli, S.M.49(3)Two varieties of wodginite, Fe-rich and Mn-rich, occur in pegmatites at Seridózinho, Paraiba State, Brazil. The mineral is monoclinic with a=9.46 Å, b=11.43 Å, c=5.12 Å, ß=91°12' (for the Mn-variety). Optical properties, micro-indentation hardness and reflectance values, and electron-microprobe analyses are presented. A discussion of previously published analyses leads to the conclusion that there seem to be two possible systems to fit the analyses of wodginite into a formula.
Zur genese einer stirnschuppe der Esla-decke (Kantabrisches Bebirge, Spanien)1970Ruhrmann, G.49(3)A special re-mapping of the Esla region (Province of Léon) brought to light an isolated block of allochthonous limestone in the frontal area of the Esla nappe. Three interpretations are discussed: 1. The block is a squeezed out remnant of the north flank of an anticlinorium. There was no movement of a nappe. 2. The block remained attached to autochthonous material during an eastward movement of the Esla nappe. 3. The limestone was isolated during movement of the nappe and was overrun by its own nappe. We can therefore call it a "Stirnschuppe" sensu Tollmann (1967). The third interpretation is most probable.
Algemene' of 'Fysische' geologie 1970Brouwer, A.; Fischer, M.M.49(3)
Environmental studies concerning Upper Devonian (and Lower Carboniferous) coastal sections of the South County Cork1970Raaf, J.F.M. de49(3)
KNGMG jaarverslag 1969197049(3)
Weichselian stratigraphy and radiocarbon dating in South Wales1970John, B.S.; Ellis-Gruffydd, I.D.49(4)There are many difficulties involved in both the interpretation and correlation of Weichselian deposits in South Wales - a fact illustrated by the multiplicity of viewpoints in the literature. It is suggested that the Weichselian stage was characterised by (1) an early prolonged periglacial phase, possibly with local upland glaciation and with some climatic fluctuations; (2) a major glaciation in which Irish Sea ice and Welsh ice played different relative roles in different areas; and (3) a shorter periglacial phase with some corrie glaciation in the uplands. There are four radiocarbon dates for the Late-glacial. The dates from Port Talbot (Glam.) confirm the age of organic deposits from Swansea Bay and provide an approximate date for the onset of the Flandrian transgression; and the date from Aberaeron (Cards.) points to the existence of Zone II organic deposits beneath solifluction earth and above glacial drifts of probable Weichselian age. There are also four dates for the Middle Weichselian, supporting other evidence for an interstadial at this time and for a later extensive glaciation by the Irish Sea glacier in Cardigan Bay. There is no unequivocal age determination for the organic content of the calcareous Irish Sea till. Palaeobotanical investigations undertaken so far have revealed that a wide range of organic material exists in the glacial drifts, including a significant amount of Tertiary pollen and spores and many fragments of Tertiary lignite. It is therefore difficult to relate the palaeobotanical evidence with any confidence to either the stratigraphy or the radiocarbon dates. However, an interglacial deposit discovered in situ at West Angle (Pembs.) may provide another pointer to the true age of the South Wales drifts; and the radiocarbon date for the human skeleton from Paviland (Glam.) should also be of major significance for the establishment of a reliable Weichselian chronology.
Premiere mesure geochronologique en Sierra Morena1970Leutwein, F.; Saupé, F.; Sonet, J.; Bouyx, E.49(4)La datation par les méthodes Rb-Sr et K-A de la roche totale et de plusieurs minéraux de deux échantillons de la granodiorite de Fontanosas (Ciudad Real, Espagne) a donné pour celle-ci un âge de 302 M.a. L'âge de ce stock tardi-ou post-tectonique, joint à des critères stratigraphiques permet d'attribuer le plissement principal de la région d'Almadén à la phase sudète.
An application of factor analysis to the interpretation of the genesis of magnetite in the smallwood mine, labrador1970Zodrow, E.L.49(4)The Smallwood Mine at Labrador City, Newfoundland, contains two recoverable iron ore minerals: specularite and magnetite. This paper inquires specifically into the genesis of magnetite using a model that statistically relates the measured variation of four variables to ideal causes that were responsible for these variations. Through the interpretation of the results of factor analysis, a theory of magnetite genesis is proposed which tentatively indentifies the Grenville orogeny as the factor largely responsible for the formation of magnetite. However, it is proposed to enlarge the factor model to include additional chemical variables which may reduce the unexplained variance in this system of variables and more clearly specify the common factors.
The occurrence of crandallite in a sinkhole near Florze (Belgian Condroz)1970Buurman, P.; Plas, L. van der49(4)Crandallite has been found in a sinkhole near Florzé where recently also halloysite was discovered. The mineral occurs in a pocket in a residual clay derived from Visean limestones. The clay is found on top of Om and Onx deposits and below Pleistocene solifluction material. X-ray diffraction patterns, D.T.A.-traces, specific density separation, refractive indexes, X-ray fluorescence patterns and chemical composition have been determined and are reported. The samples are rich in uranium.
The statistical discrimination between coversan areas in the Netherlands1970Crommelin, R.D.; Keuls, M.49(4)In 1968 Maarleveld published the results of a research of the coversand area in The Netherlands, based on geomorphological evidence and on the evaluation of macroscopical characteristics of the coversands mainly in the 105-75 micron fraction, resulting in a subdivision into 29 subareas. Each subarea could be described in terms of specified amounts (per mil values) of the three characteristics: white, black and green grains. In this study the analytical results of these principal characteristics are consider ed in a mote objective way, in order to arrive at a numerical comparison for all possible pairs of subareas. For any pair this comparison may be expressed as the sample-size N required to detect a difference as large as the one stated between the respective sample means. The N-numbers - which may be considered as difference- or similarity-coefficients have a practical significance in that they provide a measure for the discrimination between any pair of areas as to the characteristic in question: large N-numbers stand for a high degree of similarity, whereas small N-numbers mean that the areas under consideration are very different and consequently may be distinguished with relative ease. The relation between the N-number and the statistical parameters of the characteristics is discussed. A way is indicated how to arrive at defining areas such that they fit classes with a maximum contrast between the analytical data.
A Tortonian age for sedimentary rocks directly overlying volcanics in the Western part of La Serrata, Nijar, prov. Almería, SE Spain1970Zeck, H.P.; Soediono, H.49(4)A well-preserverd fauna f planktonic Foraminifera indicates a Tortonian age for a calcilutite directly overlying pyroclastic orthopyroxene-labradorite pheno-andesite. The rock series belongs to the autochthonous of the Betic Cordilleras
Rates of diastrophic movement during the Quaternary in Indonesia1970Tjia, H.D.49(4)Quaternary folding, faulting, tilting, uplift, and subsidence for several localities in Indonesia yield the following information with regard to rates of diastrophic movement. In the mobile regions the average rate of uplift with or without attendant folding amounts to 0.5 to 1.0 mm/yr. Subsidence occurs at rates of 2.0 mm/yr. As expected, diastrophic movements in the continental areas are much slower and are measured in hundredths of a millimeter annually. Wrench faulting possesses most rapid movements; rates of strike-slip movements are at least 5 mm/yr. It was also found that observation on deformational phenomena for. shorter periods yields anomalously high values of diastrophic rates. This evidence is in accordance with the spasmodic nature of diastrophism which is also reflected by the occurrence of multiple elevated terraces.
Rates of diastrophic movement during the Quaternary in Indonesia1970Tjia, H.D.49(4)Large Enclosure
Significant changes and developments in Zambian mineral industry1970Vletter, D.R. de49(4)
Beknopt verslag van het derde international geochemical exploration symposium1970Dijkstra, S.49(4)
Het onderzoek naar de toepassing van moderne luchtopnametechnieken1970Eckhart, D.; Bosman, E.R.49(4)
The occurrence of low pressure metamorphism in the Precambrian of the Middle-East and North East Africa1970Shimron, A.E.; Zwart, H.J.49(5)The occurrence of metamorphic minerals, like andalusite and cordierite indicating formation under low pressures, is described from the Elat area in Israel and the Sinai Precambrian. The study of the timing of metamorphism with regard to folding phases has shown that the metamorphism is progressive in time. The -possibility that the Precambrian of the Arabian shield belongs to a Hercynotype orogenic belt is discussed.
The occurrence of low pressure metamorphism in the Precambrian of the Middle-East and North East Africa1970Shimron, A.E.; Zwart, H.J.49(5)Large Enclosure
On the origin of several heavy clay layers in solifluction deposits of the Belgian Condroz1970Buurman, P.; Groot, G.E. de; Winkler Prins, C.F.49(5)In many places in the Belgian Çondroz heavy solifluction clays occur on top of Tertiary sands. These deposits are generally found in conjunction with fair amounts of chert and silicified fossils. In order to determine the origin of the clays, investigation of the fossils (mainly brachiopods and corals) and the granulometric and mineralogical compositions were carried out. The fauna collected in the clay deposits is typical for the upper Tournaisian and lower Viséan (Lower Carboniferous). For comparison fossils were also collected from residual clays in situ on Viséan and Tournaisian limestones. No important differences between the fossil groups could be detected. The clay mineralogical analysis also indicates that the clays in the solifluction deposits are residues of soil formation on Carboniferous limestone.
Pollen analyses of the Helvoirt river valley1970Buurman, P.49(5)Four pollen diagrams from the Helvoirt river valley (Noordbrabant, The Netherlands) are presented and discussed. Several conclusions concerning the formation of the valley and its deposits are drawn.
The complex NRM of the Permocarboniferous Bademli Redbeds1970Voo, R. van der; Klein, P.H. van der49(5)The analysis of the NRM of 27 Permocarboniferous samples from a nappe in the Tauride Chains revealed that in most samples three magnetic components were present. Two of the components are thought to be secondary due to remagnetization in Early Tertiary, and Recent times. The third and hardest component is assumed to be Permocarboniferous. It yielded an anomalous paleomagnetic direction, though the low inclination value indicates an equatorial position during the Permocarboniferous.
Stabiele isotopen van koolstof en zuurstof in water en kalk1970Mook, W.G.49(5)
Zwavelisotopen en olie geochemie1970Aldershof, W.G.49(5)
Les alterations des materiaux en oeuvre sous climat tropical1970Hyvert, G.49(5)
To our readers1970Jong, J.D. de49(6)
In memoriam Prof. Dr. M.G. Rutten1970Thiadens, A.A.49(6)
Mafic geosynclinal volcanism in the Lower Carboniferous of South Portugal1970Schermerhorn, L.J.G.49(6)Lower Carboniferous mafic volcanism in the Hercynian geosyncline of South Portugal produced spilite flows, often pillow lavas, and albite diabase intrusions. Spilites only occur in a central zone. Felsic voicanism took place at about the same time in this geosyncline: in South Portugal the mafic volcanism followed the felsic eruptions but in Southwest Spain the succession is reversed. The relationships between the mafic and the felsic activity indicate a rough juxtaposition in space and time but no genetical link. The mafic volcanics are considered to derive from the upper mantle and the felsic volcanics are thought to have been generated in Iocal magma chambers by melting in the deep crust.
A trace element study of terrace materials from Southern Limburg, the Netherlands1970Dijkstra, S.; Sutthitavil, S.49(6)The present paper deals with a trace element study of terrace materials in southern Limburg. Uncertainties and limitations of these types of studies are discussed and special attention is paid to matters like the relation between trace element content and heavy mineral association, metal ratios in various materials, and trace element trends in gravels of different age. It is suggested that discontinuities in these trends might represent important events in the development of the river system.
A geohydrologic study of east Gelderland (Netherlands)1970Ernst, L.F.; Ridder, N.A. de49(6)This paper deals with the results of a geohydrological investigation carried out in the eastern part of The Netherlands (province Gelderland). In this region the demand for water for domestic and industrial use is rapidly increasing. The present demand of 34 million m3 per year is entirely met by extraction of groundwater. With a view on the agricultural interests the problem arises what effect a further increase of the groundwater extraction may have on the productivity of the drought-sensitive soils. This study was made to provide basic data for the solution of this problem. The geological investigations have given a much better insight in the suitability of the aquifers for groundwater exploitation than existed. The transmissivity of the aquifers according to field pumping tests and well logs, varies from about 300 to 10,000 m2/day. This variation is chiefly due to fluvioglacial erosion and aggradation during the Saale Ice Age (buried glacial channels). Utilizing a finite differences equation, in which the available transmissivity values and water table gradients had to be substituted, a map has been prepared showing the intensity of the net subsurface inflow. This flow rate is of practical importance because adding to it the mean precipitation and evaporation values immediately yields the mean drainage intensity. Transmissivity values and values of the drainage resistance were used for the calculation of the drawdown of the water table by extraction of groundwater from deep wells. In general, the groundwater is fresh but remarkable differences in electrical conductivity, sulphate-chloride ratio, hardness and iron content were found in the region. At some places the groundwater temperature was also measured. The differences in chemical composition and in temperature of the groundwater were found to be in fairly good agreement with the occurrence of positive and negative net subsurface inflow.
Observation on submerged sand ripples with heights ranging from 30 to 200 cm occuring in tidal channels of S.W. Netherlands1970Terwindt, J.H.J.49(6)An investigation of submerged sand ripple fields with ripple heights from 30-200 cm in the fluvial tidal and tidal channels of the S.W. Netherlands was made. Such rippled surfaces were found in fluvial tidal channels, at the confluence of tidal channels and in pronounced ebb and flood channels. However, over large areas no ripple fields of this kind were observed. Ripple areas do not distinguish themselves from non-rippled areas by a difference in general current characteristics or composition of the bottom material, although no ripple (30-200 cm) fields were found in areas where the bottom material contains more than 15% mud. The asymmetry of ripples with heights of 30-100 cm is sometimes determined by the prevailing tidal current especially in ebb and flood channels; change of the asymmetry with the turn of the tide does occur. The asymmetry of ripples with heights from 100-200 cm showed much more constancy. It mostly did not change with the turn of the tide. The dimensions of the ripples in the fields may change rather rapidly. There is no relation between ripple height and water depth. It was observed that the orientation of the ripple crests is influenced by the spiral flow in tidal channels.
"Engineering geology" in Nederland1970Dozy, J.J.49(6)
Van de voorzitter aan de leden1971Krol, G.L.50(1)
Origin of Solnhofen limestone1971Straaten, L.M.J.U. van50(1)
The genesis of belgian and Dutch flints and cherts1971Buurman, P.; Plas, L. van der50(1)Different analyses were carried out on several Dutch and Belgian flints and cherts. As a result of the observations conclusions are drawn about the properties of flint and chert and a theory on the formation of flint and silicification of limestones through a calcium silicate intermediary is presented. Calculations on the physico-chemical aspects of this theory are presented, These calculations turned out to accord with several field observations.
Note on chamosite in sediments of the Surinam shelf1971Hardjosoesastro, R.50(1)
Processing of water-quality data by digital computer1971Creusot, M.R.; Geirnaert, W.50(1)
Subdivision of the "Cromerian" in the Netherlands; pollen-analysis, palaeomagnetism and sedimentary petrology1971Zagwijn, W.H.; Montfrans, H.M. van; Zandstra, J.G.50(1)A subdivision of the lower part of the Middle Pleistocene ("Cromerian") of The Netherlands is proposed. At least 3 interglacials are now recognized. The Matuyama-Brunhes boundary (0.7 M.y.) has been located within this sequence.
A consideration of the continuity of the Tertiary orogenic systems of Europe and Asia1971Gill, W.D.; 50(1)
Foreword Special Issue on the closure of the coal mines in the Netherlands1971Krol, G.L.50(2)
Preface Closure Coal Mines 1971Block, L. de50(2)
The melting pot of the black gold - De smeltkroes van het zwarte goud1971Rooy, C.J.M.A. van50(2)
De opgang en teleurgang van de Limburgse Steenkoolindustrie (een historisch overzicht)1971Raedts, C.E.P.M.50(2)Since the early middle ages the northern part of the Netherlands have followed its own independent energy policy. As naturally it was paramount that the supply of raw materials for the generation of energy had to be as cheap as possible, thereby benefiting local trade and industry, this policy sometimes was of disadvantage to the national coal industry. Napoleon's Mine Law of 1st May, 1810 promoted the activity in the mining industry. Towards the end of the period of French domination and during the early years of the kingdom of the Netherlands, there was only one coal mine in southern Limburg: the Domanial Mine. After the Belgian revolution of 1830 and the resulting separation of Belgium and the Netherlands the two countries went their own individual routes of industrial developments. In the area of Liege we saw the beginning of a continental industrial revolution while the northern Netherlands placed more emphasis on trade and shipping. The Domanial Mine was followed in 1852 by another one, which, however, was stopped even before the Domanial Mine closed down in 1970. The first 2 concessions after the French domination, signifying the first real emphasis on mining in Limburg, date from the years 1860-1861. It was not until 1902 that the first coal was produced from the unified Willem Sophie Mine, which exploited these two concessions. Between 1870 and 1880 another 13 mining concessions were awarded and a great number of holes were drilled. No new mines were started, however, and between 1891 and 1892 most of these concessions were cancelled. The initiative of Sarolea who obtained a concession in 1889 as a reward for the construction of the railroad from Sittard to Herzogenrath and of the Aachen (Germany) coal producers Carl and Friedrich Honigmann (who were awarded in 1893 most of the concessions that were cancelled in 1891 and 1892) meant the beginning of the modern mining industry of Limburg. The first of the 4 Oranje Nassau mines started to produce in 1899 and in 1908 all the properties of the Honigmann family went over to the De Wendel family of Lotharingen. Affiliated in this manner with large steel mills and with owners of large experience in mining, the Oranje Nassau mines started to prosper. In the meantime Mine Laura had started in 1907 and after World War I its sister Mine Julia went into operation. Concerned about the foreign influences in the Limburg mining industry a government commission was created in the year 1899. This resulted in 1901 in a law reserving all unallocated concessions for exploitation by the nation. In 1903 the first concession was assigned to a state mine, in 1915 the fourth to state mine Maurits. Finally a concession under Vlodrop was awarded for exploitation by the nation, the shafts were dug but the mine was never produced. Worth mentioning in the history of the Dutch State Mines (DSM) is that its personnel are not considered as "staff in the normal sense of the word. In 1913 the Dutch State Mines management was instructed to run the company "as much as possible as it is customary in the large private enterprise". The entire Netherlands mining industry had to find its own anyhow between the years 1900-1914 and secure national recognition. As late as in 1913 64% of its production still had to be exported. In 1919 the first steps were taken in the creation of a chemical industry by DSM, which now forms a most important element in the industrialization of southern Limburg. After World War I a couple of prosperous years followed, the years 1923 (occupation of the Ruhr district) and 1926 (major strikes in Great Britain) were very good years for the mines. Before things turned for the worse again in the thirties, production amounted to 12.2 million tons of coal in 1930. It is, however, not until 1939 that one could speak of normal conditions, but then of course the German invasion followed and the mines were put under the control of the German forces. After World War II the mines had to step in again to alleviate the energy shortage and they were therefore highly appreciated. But soon thereafter a complete change occurred in the energy market. The penetration of cheap oil, the introduction of atomic energy and the discovery of large amounts of natural gas in the Netherlands resulted in a crisis in the coal mining industry, which reached its peak in 1958. New developments like the coal and steel community, later the EEG could not save the mines and so we witnessed the end of an industry which had been of major importance to the Netherlands for many decades.
De liquidatie van de kolenmijnbouw in Limburg in het licht van het Nederlandse energiebeleid1971Molkenboer, J.A.M.50(2)A unique feature of the termination of Netherlands coal mining for which there is no precedence is the planned and gradual run down of a complete industry, because developments in the energy market made continued economic exploitation of coal impossible. Moreover, the liquidation is being carried out rather quickly and in an area of very limited extend and is therefore creating unique problems in the search for new employment opportunities. As the state owns the largest coal mining enterprises, involvement by the government was unavoidable, the more so as the mines had to be closed down before they were technically depleted with the timing being set by the availability of cheaper replacing fuels. The author discusses all the reasons which lead to the decision to close down the mines and wonders whether in retrospect these reasons justified the policies followed. In 1965 it became apparent that solid fuels were losing their importance in the Netherlands supply of energy. It could be assumed that our steel industry would require less domestic coal, while power generation was increasingly being taken over by oil and natural gas. The competitive position of the Netherlands industry demanded the use of the cheapest possible source of energy. Even the mines' own consumption of coal for the generation of electricity and the manufacturing of coke and coke-gas could no longer be economically justified. In the meantime a significant expansion of crude oil refining capacity in the Netherlands was noticeable. Its input is subject to a certain risk - as it does in all of western Europe – of being interrupted. Groningen gas, however, could absorb satisfactorily this risk element which previously has been absorbed by the coal mining industry. The decline in the share of solid fuels in the energy market has been more rapid than had been forecasted. However, the Netherlands balance of payment has not suffered as the export value of natural gas exceeded the former export value of coal. Oil consumption has also increased but so has the export of refined products. The social aspects of the guiding policy in the liquidation process are summarized by the author as follows: a. Supported by the general re-industrialization process the state and privately owned mines are diversifying their activities. b. The high rate of industrial growth has lead to increased employment opportunities, even without the government's involvement. In retrospect it seems that the policies followed were generally successful, but it should be kept in mind that human relations were severely affected and that a few weak spots remain which are difficult to rectify. The state accepted a burden of N.fl. 1750 million (approx. US $ 500 million) to carry out a policy which had to be socially and economically acceptable. It is expected that sometime in the future the final outcome will be considered favourable mainly as a result of the splendid co-operation in many fields which one has witnessed so far.
De energievoorziening van Nederland voorheen en in de toekomst1971Geertman, G.H.M.50(2)This article outlines the development of primary energy demand by the various consumer categories in the Netherlands since 1950, and discusses the shifts that have taken place in the contribution by the various energy sources. In addition, an attempt is made at extrapolating energy consumption towards the year 1980. At first, solid fuels held the dominant position, but when energy prices began to drop after the first Suez crisis, Dutch coal in particular felt the impact, and began to be gradually ousted form the inland market. Up to 1965, the decrease of the coal consumption was compensated almost entirely by liquid fuels, while after that year also natural gas began to play an important role. The consumption of natural gas increased so rapidly that between 1965 and 1969 the sales of fuel oil to industry showed a decline. Also the demand for natural gas for the generation of electric power and for home heating purposes has gone up sharply. In 1969 the share of natural gas in the overall energy consumption was already as high as 25% that of oil being 59%. Between 1965 and 1969 the overall demand for energy rose more than 8% annually, to reach a level of over 60 million tons of coal equivalent. The increase estimated for the period 1969-1980 is almost 6% per annum, which means that in the latter year the overall consumption will be more than 110 million tons of coal equivalent. The consumption shift on the Dutch energy market is expected to continue. Eventually, natural gas will provide more than 40% of energy demand in the Netherlands, while the share of mineral oil will drop to below 50%.The growth of the gas consumption by the three categories referred to above will persist. Special mention should be made in this connection of the increasing use of central heating installations, which is largely due to the introduction of natural gas. Since the price of natural gas has been coupled to that of heavy fuel oil, gas will remain a very competitive fuel for large-scale consumers. Nevertheless, liquid fuels will retain an important position, not only in the transportation market and for nonenergetic purposes, but also - be it to a lower degree - as a domestic heating fuel. In industry and electric power stations oil is experiencing severe competition from gas. After 1975 nuclear energy may also become important as a power generating agent. Eventually, the use of coal will come to be restricted to the iron and steel industry.
Vijf jaar mijnsluiting en de gevolgen voor het personeel de periode 1965-19701971Jochems, D.B.50(2)In this contribution the author discusses the fundamental social aspects that have prevailed during the personnel reductions amounting to 30,000 workers during the last 5 years. Individual problems have of course occurred and the transition has been more successful for some than for others. In sum total we can say that the consequences of the closing of the mines for its personnel has been less severe than one might have expected. In mid 1970 the Netherlands coal mining industry still employed some 15,000 people. By analogy with the reduction of some 30,000 the previous 5 years one might expect the remainder to be run down in another 2,5 years. Mr. Hellemans in his paper will explain why this is not so. The author of this paper limits himself to a review of experience gained so far. One is inclined to forget that the Dutch State Mines (DSM) employed 5 years ago some 10,000 workers in its chemical industry (now some 12,000), this number is not included in the highest number of workers that the mining industry had in its service since World War II of some 55,000. Programmed reductions started in July, 1965. Before, between 1958 and 1965 there had been a quiet attrition of some 1,500 men per year. In 1965 the rate of reduction was accelerated to 6,000 men per year. DSM led with reducing its personnel in the solid fuels business to 1/6th of its former number, the privately-owned mines (8 in total) to somewhat less than half. Contractors and suppliers suffered of course also, but reliable information on their position is not available. As far as coal mining is concerned, the reductions affected some 1 in 4 workers in southern Limburg and even 1 in 2 workers in the eastern area where the mines are located. Re-employment opportunities are naturally of paramount importance in the area of the mine closures. The author explains that in the past it had been too readily assumed that restructuring would succeed only if for each surplus miner an industrial position would be available. However, during the restructuring phase a number of miners moved to job opportunities outside Limburg. Furthermore, a number were withdrawn from the list of employables because they were retired on early pension. As a result of these two facts only 50% of the miners that were withdrawn from the mines had to be placed in newly created positions in southern Limburg while some 10% were placed with local social labor schemes. The remaining 40% have been retired or are receiving a financial allowance until they reach retirement age. Not 30,000 industrial jobs had to be found but only half of that amount. The article contains statistical data on the jobs vacated until the middle of 1970. As a rule those who are being released qualify for unemployment compensation or a financial allowance to bridge the gap to the lower pay which they will have to accept in their new jobs. One of the major problems concerns the adjustment of the underground miners, who have high wage scales, to the much lower wage levels that prevail in industries at the surface. It is evident, however, for reasons explained in the paper, that only 17,000 of the 33,500 personnel released have qualified for compensations under the rules explained. In principle all the mines are now following the rule that no one will be released unless there is suitable alternative employment or terms for early retirement are met. Economical and production/technical considerations now take second place to social principles. A "Council of Guidance" can be called upon for assistance by any mine. The usual procedure is that job opportunities are located and investigated and that qualified candidates are brought forward by the mines. Retraining programmes have to be designed and about 650 staff and 4,150 workers have been prepared for new employment by retraining. About 25%of available staff and about 10% of the manual workers have found employment outside the province of Limburg. People of 40 years and over form the hard core of the reduction programme as they are the most difficult to place. It is gratifying that so far employment has been developed for about 2,000 handicapped workers.
Het gecoördineerde personeelsafvloeiingsbeleid voor de nog resterende jaren van het mijnsluitingsproces - de periode 1970-19751971Hellemans, A.50(2)
Scholingsaktiviteiten in het kader van de herstructurering in Limburg1971Loos, J.50(2)Due to the closing of the coal mines a significant source of employment is disappearing. Many of the skilled professionals of the mining industry are, from the point of view of education, training and aquired skills, unit for the types of alternative employment that is being offered. Training of various types, from adding to a man's skills to complete retraining is needed and forms the subject of this paper. One of the types of training is provided by the centres of professional training for adults, another and by far the most important is the reschooling by the employers or by special job training centres, following the guidelines as laid down by the Directory General of the provincial employment office. Certain aspects of reschooling are already covered by other authors in this booklet. The favourable results obtained in the retraining and reschooling programs of the ex-miners is for a large measure due to the excellent co-operation between the provincial employment authorities, industry, the labour unions and the European Coal and Steel Community.
Taak van de mijnschool in het herstructureringsproces1971Haverschmidt, R.50(2)In 1965 the Mining School in Heerlen was employed for the re-education of underground mining technicians in order to achieve that these staff could obtain equivalent jobs in industries outside the mines. In previous years the Mining School, an acknowledged institution for advanced technical training, had trained 2,250 mining supervisors and 150 mine surveyors. Retraining would therefore be carried out in a familiar place where the material was being modified on a routine basis to be suitable for changing employment conditions. In 1964 the Mining School occupied new premises which allowed the re-educational program to be handled in the most efficient manner. The cost of re-education could be paid out of contributions received from the Dutch Government together with allowances from the European Authority for Coal and Steel. Although initially it was assumed that only staff under 40 years of age would be re-educated, this upper limit was successfully increased in the course of the years. The paper deals with the didactics, including the various streams of re-education and the placement of those who passed the final exams, 10 different reschooling possibilities could be recognized. At present 380 people have been re-educated with over 190 still at school. Continuous contact is maintained between teacher and pupil when the latter is following practical courses in various industries, one of which may employ him eventually. Much special effort is asked the schooled staff in planning the reschooling programs and in guiding the pupils through the process. Some thought is given to the future of this school in these days of accelerated obsolescene of technical skill due to rapid technical developments. The Mining School has proven that re-orientation and the necessary re-education of staff towards other industries can successfully be achieved.
Omscholing en wederaanpassing van ex-mijnwerkers1971Koene, G.B.M.L.50(2)The tenthousands workers who are still employed in the mining industry are very much involved in the further closing of the coal mines. For alternative employment away from the mines, a planned reschooling program is essential. When selecting candidates for each of the reschooling courses all those data are collected from superiors, personnel services, psychological and medical staff, which may be relevant to a man's reschooling program and further employment. In general terms all ex-mining staff such as technical, administrative, supervisory or subordinate adjust well to employment in unrelated industries. Results of reschooling are, so far, very favourable, and hereby we specifically include the "older" workers. The latter are personally highly motivated as society and industry were of the preconceived opinion that older people would be difficult to change over to other types of work. This last point is subject to intensive study these days, and there are indications that reality is quite different and varied and that older workers have been very much prejudiced against. Experience with miners has contributed to the studies mentioned. The closure of the mines and the re-industrialization of the mining region of Southern Limburg has not only created serious problems for thousands of workers, but has especially affected those that were handicapped, physically or mentally, which can be due to physical/psychological conditions or age. Realization of these handicaps by employers and the studies thereof can lead to results that reach further than the mere re-employment of ex-miners. Anyone providing selective and adjusted employment can benefit from what has been learned in Southern Limburg.
Naar de education permanente1971Heiligers, G.J.50(2)The second phase of the restructuring of Southern Limburg has only just started. A redrawing of the municipal boundaries has only reached the planning stage. Yet the education of the youth and, simultaneously, the reschooling of the not-so-young are of immediate concern. The new educational system will again have to be of a very special nature and content like the existing system which is now going to be abandoned. The new system calls for: - institutes for reschooling - new technical institutes offering a wide and diversified program - institutes specializing in refresher courses. These three elements form the basis for an incipient "Permanent Education", the primary aim of which should be the personality-development of its students. Additional fresh capital will have to be invested in what is most important: the potential of our youth, which potential will shape the future of the region. The financial means which this will require will have to-be found. A first start has been made with the design of a new type of school in which technical developments will be constantly taken into account. In the future one will have to ask himself in what ways a certain educational system will influence society, as a matter of fact: modern education is entitled to play a leading role in today's society. There is no lack of professional men in Southern Limburg to give this type of education. For the time being the accommodation is also sufficient. The financial backing, however, is still lacking. It is here that the assistance of the Government is most urgently needed. The University which Limburg will have must be supplemented by "intermediate level" schools, And, last but not least, expeditious and strong action is required.
De sociale begeleiding der industriele herstructurering1971Lebens, P.J.C.50(2)The shutdown of the mines affects the social climate in Southern Limburg to a large extent, necessitating intensive social assistance for all concerned. The author recognized 4 distinct phases in the restructuring process. Initially the Provincial Administration of Limburg studied possible social repercussions of the shutdown of mines on the miners, the other professional population, housing, municipal financial matters and mental public policies had to be developed. Thereafter a start was made to carry out the suggested plans and proposals and two management-advice committees were instituted for proper planning and execution of the projects. The third phase saw several additional measures and precautions which had not been taken into account before. For example, after it was found that some 4,500 semi-invalid workers would come out of the mines, special workshops had to be provided for, which operate satisfactorily due to the present favourable economic climate. Favourable economic conditions also are the reason for the successful placement of the other miners that became available on the labour market. Of course, much attention has been paid, in particular during the first years, to all other personnel which had to leave the mining industry. There was a definite need for advice on the legal status and assistance in legal and financial matters. In 1968 some 6,000 persons made use of a special office dealing with these matters, which was operated by the unions, but also assisted non-union members. One of the problems one had to face was the reduction of income the ex miners had to get used to when working in non-mining industries. Not only were the miners and their families suffering but so did other groups of the population in the area. The closure of the mines created initially a high rate of unemployment which, however, was rapidly reduced because people moved away from the region or started to commute to jobs outside the region. Certain difficulties remain, which are likely caused by divergencies in quality and basic education. Although on the one hand much money is needed to attract new industries, the financial position of the municipalities, on the other hand, deteriorated due to the closure of the mines. As a result the social infrastructure occasionally suffered, though about Hfl 30 million (US $ 8.4 million) was made available by the government during 1967-1970 for social projects. An important aspect of social welfare is the care of mental public health: the liquidation of an industry which provided a living for almost half of the South Limburg population inevitably has mental repercussions. Many people had to retire earlier than previously; for others the sense of security disappeared. In the framework of social welfare preventive measurements have to be taken, to be carried out by sociologists and social psychologists or psychiatrists. During the last three years much work has already been done; this, however, should also be continued. The fourth phase, which is starting today, involves the co-ordination and planning for the problems discussed above. A start had been made, appointments are carried through, the ultimate goal is not only to contain the problems but also to actively build a new society.
De rol van de vakbeweging bij de afbouw van de mijnindustrie1971Hubben, A.J.50(2)Since 1945 the Catholic Federation, together with the Netherlands Catholic Mining Union (NKMB, 65 per cent organized personnel) and the Catholic Union of Mining Officials (KVM, 85 per cent organized) requested the Government repeatedly to define its point of view regarding the difficulties of the mining industry. The author, chairman of the KVM, describes the active influence which the Federation exerts on the restructuring of the mining region, a logical consequence of the good and positive relationship that has prevailed for years between employers and employees in the mining industry. The role of the Trade Unions was in this manner formerly recognized by the authorities. Trade Unions were involved in policy making for the mine closures, the resulting personnel reductions and the control thereof. They also contributed positively to the re-industrialization of the region. The one-sided industrialization over the Iast 70 years in Southern Limburg had brought about a mono-culture; that dislocation of the work and living environment and the end of prosperity should be avoided was a subject of much concern to the Federation' The guiding principle therefore was that the shutdown of the mines should only be organized in such a way that equivalent employment opportunities would be available. This problem both qualitatively and quantitatively is unique in the Netherlands, involving directly or indirectly some 300,000 people. The unions themselves assumed responsibility for these events and their consequences. They worked closely together with the Government and employers to achieve the best results. Much personal grief still remains, however, it is only fair to mention that at least partly due to the role of the unions, the Netherlands is the only country in the Common Market where the shutdown of mines has been organized within a framework of restructuring, embracing the whole of the industry and including a social planning for all personnel. Labor participates in these matters through its representation on the Council of Guidance which is mentioned by Mr. Hellemans in his paper. Common Market people agree that a lot of good work has been done. Special attention is given to the financial repercussions, in particular regarding pensions. The unions assist their members in finding new jobs and are in the forefront to get a new university in Maastricht and to revamp the Mining School. The author maintains that officials and miners would like to continue to be members of their weII known unions and their regional affilations. Some of the familiar working conditions and labor relations have to be maintained while the industrial climate is changing. For this the full co-operation between employers and employees is essential.
Wat betekenen de veranderingen in de mijnstreek voor de vrouwen en voor de gezinnen?1971Stollman, E.H.M.50(2)A few years ago few housewives could believe that the mines really would be closed down, but now they are already suffering the consequences of the closures. In certain cases their husbands found employment outside the mining industry, others went on early pension. A third group was transferred to the chemical side of their employers' business, for which they were not trained, more often than not resulting in friction with their new colleagues. Many housewives have quite some trouble in containing their husbands' unhappiness with respect to the changed situation, he has to worry about different things than he was used to, the daily routine had to be changed and naturally the changed circumstances affected the peace in the family and the relationships between parents and children. It was realized that children probably need a better education than father ever had and it generally is the mother, being closer to her children, who had to bear the brunt of the problems. Not only had the housewives to adjust themselves and the children to the enormous changes in the social circumstances, she often had to go to work in order to make up part of the loss of income suffered by her husband, as most new job opportunities were less lucrative than those of underground miners. Generally, the greatest part of the burden of the changed climate will have to be carried by the housewives according to the author. It will depend mainly on her whether future living in Southern Limburg will be worthwhile. The paper ends with a discussion along the different activities underway in the different women's organizations to alleviate the problem which can be catalogued as follows: a. Activities focussed on the housewives directly; b. Co-operation with other agencies in determining restructuring policy; c. Publications and other means to recognize problem areas,
Mijnsluiting en mijnwetgeving1971Martens, A.H.W.50(2)No one objected to the principle of closing the coal mines when oil and gas pushed coal out of the energy market. Social repercussions were successfully contained. Technically, however, there are two problems which could lead to legal complications but for which there exist no juridical precedence. There are firstly the necessity to fill up the main shafts and secondly the continued certainty that mining damage would be compensated for even after the abandonment of the mines. The mining law of 1810, dating from the days of occupation by the French, which is, at least partly, still valid in the Netherlands, has no chapter dealing with closures of mines. Only in 1964 a very general and largely incomplete regulation covering this matter was incorporated in the law. The initial requirement to have the shaft completely filled was after all not necessary. The question of the subsurface water level is dealt with in another paper. Regarding mining damages, a system was chosen in which the mines Oranje Nassau, Laura and Vereniging and Willem-Sophie quaranteed voluntarily to remain fully responsible for all possible damages, also after the shutdown of these mines. A special foundation has been established by the abovementioned private companies to ensure payment of any future claims towards damages, and particulars concerning the funding of the capital is fully described. The Dutch Government took over the Domanial Mine, for which mine, as well as for the four existing State Mines, no special regulations are thought necessary.
Beveiliging van het maaiveld van verlaten mijnschachten in Zuid-Limburg1971Schilp, J.P.50(2)In the South Limburg coal mining district, abandoned pit shafts have to be filled up - at least in the overburden section - in view of the loose nature of the overburden, and the presence of dangerous gasses in the underground workings. In other coal basins with comparable conditions, shafts have been filled down to the bottom with clastic material, generally with special provisions near the shaft insets. In several cases this method resulted in severe subsidence of the filling material and release of firedamp at the surface. In view of this, the following methods have been applied in South Limburg, also taking into account the urbanization of the area. Method I: The supported plug In nine shafts, a concrete closing plug has been placed in the shaft, at the level of the highest loading station. The plug is supported by the floor of the station. The shaft section above the plug is filled up with clastic material. The shaft mouth is capped with concrete. This method was used where the overburden is thick (average: 210m), the shaft opening large (average: 23 sq.m), and the shaft wall smooth. Method II: The shear prop a. In five cases the shaft has been filled up with concrete from the highest loading station to the surface. This method has been followed in the case of a thin overburden (average 43 m), with a short distance from the highest level to the overburden (average: 7 m) and a small shaft opening (average: 11 sq.m). b. In four shafts a shear plug has been placed above the highest level. The section above the plug is filled with clastic material. The required length of the plug depends on the distance to the surface, the size of the shaft opening and the roughness and nature of the shaft wall' The shaft mouth is capped with concrete. The average length of the filled section is 104 m, the average shaft opening is 10 sq.m and the walls have a rough and irregularly shaped surface. c. In three shafts, which have been filled over a considerable length owing to the prevalence of special conditions, a filling of concrete and clastic material, used alternately, has been applied. The concrete sections (shear plugs) are either over or opposite the shaft insets. The topmost shear plug completely separates the surface from the highest level. The shaft mouth is capped with concrete. The fillings with one exception, have shown only slight subsidence. Costs are only 20-50 percent of the amount for filling up the whole shaft and providing barriers at the level of the shaft insets.
Mijnwaterproblemen in het kader van opeenvolgende mijnsluitingen1971Crasborn, J.R.P.; Heuvel, H.N. van den; Kimpe, W.F.M.; Maas, W.50(2)The mine water problem is dealt with by 4 authors in 4 parts and a review. In the first part "Problem definition and preliminary studies", the study made in 1966 on the possible difficulties operating mines might expect as a result of the closing of surrounding mines, is discussed. It was evident that operating mines had to be protected from yet unforeseen water breakthroughs. In the beginning in 1968 it became known that the German Mine Gouley of the "Eschweiler Mining Co." would be closed and that in 1969 their main pumps would be shut down. The water influx of this mine was about 13 m3/minute (57 US gallons/second) with a peak of 15 m3/minute (66 US gallons/second). As there exist many underground connections between the different mines on and between both sides of the border this water was expected to flow directly across the border into the Netherlands Domanial Mine and from there, together with the water of the condemned Mines Domanial and Willem-Sophie, to other mines in the Netherlands. However, the pump capacity of the remaining Netherlands mines would be insufficient to cope with this additional water influx. After numerous discussions between the different mine owners it was recommended to proceed with the execution of project "Pump Mine Domanial". As can be seen from the drawings several water retaining dams would have to be built, to protect the mines and to collect the water of the mines Gouley, Domanial and Willem-Sophie in one basin. With the assistance of vertically submerged pumps the water level in the basin could be maintained at 310-315 metres (1030-1050 ft) below the surface level of pump shaft "Beerenbosch II". In part II the execution of project "Pump Mine Domanial" is discussed, dams were built and pumps placed. The building of one of the dams cost more than Nfl. 500,000 (US $ 140,000) due to adverse circumstances. However, had this dam not been properly built and a leak had occurred, then the drainage level to other mines would have been 100 metres (330 ft) lower, and the presently available hanging pumps would not have been able to cope with the greater depth. Furthermore additional costs for deeper pumping (Nfl. 150 000 is US $42,000) and for 5 months earlier pumping (Nfl. 250,000 is US $70,000) would have been incurred. The manner in which the dams were constructed is also discussed. Because man may never reach them again later on they had to be built as water-tight as possible. It is also explained why shaft Beerenbosch II was selected for pumping and why the vertical submersible pumps made by Ritz were chosen. The total cost for the construction of the 12 dams amounted to Nfl.2.1 million (US $600,000); for pumping equipment and auxiliaries Nn. 2.3 million (US $640,000). During the execution of project pump mine Domanial and because exploitation of Mine Willem-Sophie had to be continued, the pumping of the de activated Mines Domanial and Gouley had to be continued at a cost of Nfl. 700,000 (us $195,000). The third part discusses the geological studies of the last few years, especially the hydrogeology was intensively studied. It was concluded that as a result of the filling of the underground cavaties with water, the low pressure entry points and especially those producing brackish water, will cease to produce. It is explained why the major "Willems" fault zone could be utilized as a water barrier between the area to the south and the mines located to the north of it. In Part IV the rise of the water level in a closed mine is discussed. The rate of rise in the different mines depends on several factors, about which little is known. One had to start from assumptions, although water level measurements were carried out in one of the mines. In the review the expectation is substantiated that during the 1st quarter of 1971 a level of 170 metres (570 ft) below Amsterdam harbour level wilt be reached, with the result that "Pump Mine Domanial" will start to operate. It is concluded that it is reasonable to expect that pump mine Domanial together with the pump capacity of the still active Mine Julia will be able to protect the mines that are to be closed down in the future from water influx from the mines closed down already. It is realized, however, that there still exist 2 potential water influx locations on German territory. These are old tunnels of the mines Anna and Nordstern. How to tackle these new "discoveries" is a subject for further study.
Werkzaamheden van het geologisch bureau van de Rijks Geologische Dienst te Heerlen, voorheen en thans1971Kimpe, W.F.M.50(2)At the end of his paper the author provides his own summary, when he states "that the character of the activities of the Geological Bureau did not essentially change as the years went by". What did change was the quantity of certain investigations which were done for third parties. The article contains a tabulation of the number of reports, publication and of papers presented during the last decade. There is an increase in recent years in the number of studies on surface minerals, and also in the number of times the Bureau's advice was sought in connection with the exploration and exploitation of potable or industrial water. This directly reflects the increasing industrialisation of Southern Limburg. The Bureau was also more frequently consulted on matters of road construction. Surprisingly in these days of mines closing down. requests for advice on their part appear to be more frequent than had been expected. As from 1st January, 1968 the two geological institutions then existing in this country were re-organized into the one Geological Survey. After 60 years the Geological Bureau for the mining area ceased to be an independent unit. Its history goes back to 1907, the year in which the mining industry became actively interested in the geology of Southern Limburg. Geological mapping was also started, and likewise the Bureau was put in charge of the study of palaeobotany, the drawing up of a stratigraphy of the Carboniferous and the correlation of the individual coal seams. Both in 1927 and 1935 as in 1951 and 1958 congresses of carboniferous stratigraphy and geology were held at Heerlen. These contributed to the reputation the Bureau enjoyed abroad. The above re-organization was primarily prompted by the direct interest which the Ministry of Economic Affairs had in the increasing exploration for and exploitation of natural gas. The present paper lists the six newly created departments, which deal for instance with the investigation of the North Sea, the geology of petroleum and natural gas reservoirs in as far as they concern the Netherlands, etc. The Bureau's staff numbers six graduates and 29 non-graduates. The Bureau's achievements in the field of Carboniferous stratigraphy and of mining geology are reported in detail. The Fossilium Catalogus, of which 76 parts have already appeared, will soon be complete. Repeatedly foreign companies called on the Bureau's expertise, mainly for the stratigraphy of the Carboniferous in coal basins or in exploration wells. The next chapter deals with the practical mining geology, and emphasizes that the new methods of investigation serve to give better and more efficient information to the mining industry. The paper reviews the activities of the Bureau in its eight different aspects, and recalls that also in behalf of the "Pumpmine Domanial" several geoÌogical and hydrogeological reports have been produced. A renewed exploration of the Netherlands, with a new set of maps show the results, is necessary. The hydrogeology, as practised by the Bureau, is gaining importance in recent years because of the increasing demand for potable and industrial water. During 1969: 57 million cubic metres of ground water were produced in Southern Limburg, or, if one includes the middle part of Limburg: 85 million m3. More research is required to substantiate the expectation that this production can be doubled.
De herindustrialisatie van Zuidelijk Limburg1971Bloemendal, J.50(2)This article gives a brief historical outline of the decline of Holland's coal mining industry - concentrated in South-Limburg - as well as a description of what has been achieved in the field of industrial redevelopment of the region and of the future prospects. At the same time, it outlines, the steps taken by the Dutch Government and the activities displayed by DSM in this reindustrialization process. These activities are enumerated in the following items: 1. Analysis of labour potential according to quantity, quality and time of availability. 2. Stocktaking of needs of industrial sites that are offered and that are available or about to become available, and of the positive and negative qualities of these sites. 3. Promotion of cooperation with and between the bodies concerned, viz., the Ministry of Economic Affairs, the Provincial Authorities, the various municipalities united in "industrieschappen" - and the mining companies. 4. Gathering as much information and literature as possible about all subjects that may be of importance to the parties interested, so as to be able to keep parties fully informed. This information has been summarized in an attractive book entitled "Facts and Facitities; South Limburg, an excellent location in the Common Market". 5. Giving effective publicity to the possibilities offered by South Limburg. 6. Assisting entrepreneurs in the development and legalization of their plans and, in so doing, acting as their sparring partner. 7. Designing financial structures for filling the gaps in the "Grant Schemes". 8. Carrying out constructional engineering work (the only assistance for which a fee is levied). 9. In certain cases, offering participation in projects that are in need of risk-bearing capital. L0. Offering temporary accomodation in DSM buildings for projects requiring a quick start. Finally, the results obtained are presented, the present situation examined and the future prospects discussed' The conclusion is that the majority of the collieries has been closed without causing any unemployment' The situation is veiled, however, first because a number of people has retired prematurely, second, because of increasing employment of workers in Germany that travel to and from, and thirdly, owing to migration. That is why the grant schemes should continue to exist and be partly changed to meet the situation.
Regionaal beleid in het herstructureringsgebied1971Wilbers, J.H.M.50(2)In this paper the problems related to the restructuring policy in Southern Limburg (including that part of the middle of Limburg eastward of the Meuse river) are discussed. In mid 1965 the mining industry employed 45,000 men which represented 50% of the industrial population. The total number of male employables in the area of restructuring defined above amounted to 186,000 in late 1965 and is expected to reach 190,000 by the end of 1975 and 228,500 by the end of 1985. How these figures are arrived at is discussed in detail and it is concluded that new employment opportunities to be created during the period 1960-1975 amount to 49,400 and to 39,300 for the period 1916-1985. The author claims that initially far too much attention has been given to employment opportunities in industry and not to service and other peripheral activities. Since 1965 more than 30,000 mining jobs have disappeared. From 1966 till 1971 86 new industrial projects have been created with a forecasted number of 17,000 jobs, of which 61 projects of 8,000 jobs have been realized. Already existing industry grew by 2,800 jobs. Since the end of 1969 growth has been stagnent, mainly due to emigration from Limburg, the early pensioning of miners, the employment of handicapped miners in social schemes and the commuting the highly paid employment in labour - short Germany. Furthermore the active recruiting by Belgian industries and the personnel policies followed by the mining concerns have aggravated this situation. Even during the present boom, results of restructuring have fallen off and if a mild depression were to occur, trouble on the employment side might be expected. According to the author the limited restructuring policy has to be reshaped on a much broader regional basis. With a new and more imaginative policy we should also want improved labour mediation, a systematic reschooling policy, a larger and more flexible employment potential and a more selective investment policy. Improved economical, social and fiscal policies are feasible for the benefit of Limburg. It will serve no purpose to hold the proposed new policy pending the complete integration and harmonization within the European Economic Community. With relatively minor direct Governmental involvement much can be accomplished in the outlying regions of the Netherlands.
De oostelijke mijnstreek als sluitpost van de herstructurering1971Smeets, J.G.50(2)The chief executive of one of the largest mining communities, Kerkrade, who also is Chairman of the industrial board of the Eastern mining area, poses some critical comments on the social measures taken in connection with the mine closures and some of the favourable opinions expressed by other authors. By the 1st of January, 1970, a total of 8,000 new employment opportunities had been provided for by industry in Southern Limburg. With governmental support only 3,300 of these jobs were filled by ex-miners, although at that time 32,000 mining jobs had already disappeared. The guiding policy that no mine closures would occur without having provided for alternative employment opportunities, proved to have a theoretical value only. As a result one is at the present time feeling much less confident about coming developments in the labour market of the Eastern mining region that one felt a year ago. In reality, the situation is even worse that the figures indicate and according to the author "the real problem has been circumvented". Re-industrialisation is practically stagnant, mainly because of the competitive forces in the labour market which are aggrevated by the large scale of commuting of labour to Germany. According to the author, the statistics at the moment give a confused picture and fail to show an improved employment climate. Commuting across the border gives the impression of full employment in the area, but it would only take a small fluctuation in the economic climate across the border to create a serious problem in Limburg, for which no employment vacancies are being reserved. The consequences of the re-structuring process are most severely noticed in the Eastern mining region. It is therefore necessary that strong concerns are being created which most likely requires additional government support. The possibility of re-locating government offices over the country should also be kept in mind, and in this respect the Eastern mining region would like to have the same system of transfer allowances as has been authorized for Eastern Groningen. Mr. Smeets points out that there has been no compensation for the little understood departure to another are with employment problems of the "Industrialisation Group Dutch State Mines". In his opinion it is the duty of the government to create and maintain another such employment group in the mining region.
Herstructurering en ruimtelijke ordening1971Woude, J. van der50(2)About 70 years ago the geological and geomorphological aspects of Southern Limburg were going to be used to advantage. The first aspect gave rise to coal mining and the exploitation of marl, sand, gravel and clay; the second aspect stimutated the tourist trade. Mining, however, had a negative influence on its environment from different points of view, such as natural beauty and living conditions for the community. In the eastern part of the mining area ten mines were opened up; in the western part only one. In addition to the development of roads, railroad and canals, accelerated and often haphazard housebuilding was the result, creating, however, an economic mono-structure with the exception of the chemical industry of the DSM. Like everywhere else in the Netherlands, environmental planning was not taken seriously until after world war II. Firstly the western mining region was tackled; the plan for the eastern mining region is at present under review. Planning for the western region appears to deal with the various villages and town separately. The north-south running highway (E-9) will be the backbone for all traffic. In addition attention should be paid to touristic attractions. The western region, however, is less of a problem as it already has a new car manufacturing plant and less workers. Planning for the eastern region, where about 40,000 out of in total 50,000 miners of Southern Limburg live, had to be approached in a completely different way when compared to the western region. Industrial areas had to be developed for suburban developments. One notices a clearly defined regional policy, for the eastern region a completely revamped road system is an essential requirement and it puts planning in the eastern and western regions on equal footing. The author stress the importance of planning on a provincial level. The new regional planning should encompass the whole of Southern Limburg and be able to co-ordinate short and long-term goals in process-planning type activities. By the time the last mine is closed down in 1975, major problems will remain in the eastern region and there is not yet a consensus of opinion how to solve them. In balance, although there is ample cause for satisfaction with the results of the restructuring program, there are still plenty of problems left. The basic information on the labor situation is often confused, how many people have left the area, or are planning to leave? How many are finding employment across the border in Germany and how many are planning early retirement? In short, how will the labor force develop in the near future? What is required for proper planning of policies and priorities must be agreed upon now, such as an overall plan encompassing all of Southern Limburg, co-ordinated with the short- and long-term plans of the province and its municipalities. A way must be found to direct municipalities and their planning so as to be in line with the long-term goals of the province.
De ontwikkeling van de infrastructuur i.v.m. de sluiting van de mijnen1971Horsmans, G.A.A.50(2)In a first Governmental note it was concluded that some 10,000 new jobs would have to be created as a result of the closing down of the mines. The government appropriated Hfl 62.5 million (US $ 172,500) for the improvement of the infrastructure in Southern Limburg. In addition a number of public works would be carried out earlier than planned systems, which did not help to stimulate the construction of a modern road-system. Any other industry employing several tens of thousands of workers would have required better roads. With the imminent closure of all the mines in 1975 a much more extensive program for the improvement of the infrastructure is necessary. The author deals successively with the following categories of public works: 1. roads, 2. waterways, 3. railroads, 4. airport and 5. purification of sewage and industrial water 1. Ever since Roman times the north-south link (the present E-9 motorway) has been the main artery, if one excepts the road Maastricht-Aachen-Cologne. At this moment a complementary east-west road system is being developed. The mining district is bypassed by the E-3 road (Antwerp-Eindhoven-Venlo-Ruhr area) to the north, and by the E-5 road (Brussels-Liege-Aachen-Cologne) to the south. The E-39 (Antwerp-Elsloo-Heerlen-Bochholtz-Aachen), however, runs right through the mining district and the bridge crossing the Meuse will undoubtedly become inadequate. The planned road Maastricht-Heerlen (estimated costs 90 million guilders or US $ 25 million) can be linked up to the E-9 near Maastricht. The second major provincial road construction project is the completion of the north-south link Roermond-Kerkrade. Before long the province will be connected to the European road system by the E-9, E-3 and E-39 roads. Other roads have been planned to open up new industrial sites. Not only the government, but also the province and the municipalities have contributed towards improving the road system. Furthermore the municipalities are constructuring roads for the same purpose. The limited number of waterways are navigable for ships of up to 2,000 tons. The good road system is offset by poor rail connections. The author mentions several requirements: the rail connection between Maastricht and the eastern part of the mining district with Aachen needs improving. In 1971 an hourly service between Maastricht and Liege and between Maastricht and Aachen will probably be realized. The railways between Maastricht and Hasselt and between München-Gladbach and Roermond, however, will probably remain closed for passenger traffic. It is obvious that for goods traffic also Southern Limburg is insufficiently integrated into the European railway system; moreover, Limburg has voiced a protest against the closing down of too many loading and unloading facilities. 4. Southern Limburg's airport plays a distinct role in the industrialization process. In 1969 well over 100,000 air passengers passed through it. 5. The treatment of effluents requires special installations. In a few cases the government and the province have furnished together 65 per cent of the construction costs. There are plans for Hoensbroek, Sittard and Born, requiring over 51 million guilders (US $ 14 million), and a plan for Roermond in which another 8 million guilders (US $ 2.2 million) are involved. These projects will not be undertaken unless they are liberally subsidized. There remain certainly plenty of things to do.
Statistisch overzicht van productie, bezetting en prestaties van de Limburgse steenkolenmijnen1971Westen, J.M.J.50(2)
Samenvatting van de eerste nota inzake de mijnindustrie en de industriële herstructurering van Zuid-Limburg197150(2)
Samenvatting tweede nota inzake de mijnindustrie en de industriële herstructurering van Zuid-Limburg197150(2)
Preface Special Issue "Research on Sedimentology and Sedimentary Geology in The Netherlands"1971Jong, J.D. de50(3)
Some sedimentological aspects of the fluvioglacial outwash plain near Soesterberg (The Netherlands)1971Augustinus, P.G.E.F.; Riezebos, H.T.50(3)The fluvioglacial outwash plain near Soesterberg (The Netherlands) is a deposit, built up during the melting of the Saalian ice, by a braiding river system on the ice-free side of the ice-pushed ridge of Amersfoort. The variation in the grain-size distribution of the sediment is great. Sorting is very poor to moderate. This indicates a high stream velocity, though fluctuating, combined with a huge supply of debris. The parallel to the principal stratification plane bedded strata alternate frequently with depressions, which are filled up laterally, showing a "festoon lamination".
Characteristics and regional implications of a belt of high-energy coastal deposits in the Barremian of Provence (SE France)1971Burri, P.; Masse, J.P.; Wagner, C.W.50(3)In the Barremian Orgon limestone of southern Provence, a belt of high-energy coastal deposits of regional extent can be traced over approximately 90 km along an east-west axis from the border of the Massif des Maures to Martigues. In this belt, coarse-grained beach beds are closely associated with muddy protected shallow marine or intertidal deposits. Such an alternation is typical for a system of migrating carbonate spits and their protected lagoons, as observed in the Recent of the Persian Gulf. The Barremian belt of coastal deposits seems not to coincide with an ancient regional shore line. It appears to be controlled by east-west striking structural trends, which have been active in Provence since the Late Jurassic. The formation of this belt anticipates the most conspicuous tectonic event in this area during Cretaceous times - the Albian uplift, known in literature as "Isthme Durancien".
Carbonate facies of the Santa Lucía Formation (Emsian-Couvinian) in León and Asturias, Spain1971Coo, J.C.M. de; Deelman, J.C.; Baan, D. van der50(3)Three lithofacies are distinguished in the Santa Lucía Formatíon: grainstone facies, packstone facies and birdseye facies. The lithofacies pattern suggests three depositional environments. An area of wave and current action (grainstone facies), a quiet and sometimes restricted lagoon protected by the extensive shallowness of the entire platform (packstone facies) and an intertidal to supratidal part (birdseye facies).
Q1MdQ3 indices showing grain-size distribution on maps1971Doeglas, D.J.50(3)The use of Q1MdQ3 indices for classification and distinction of environments has been advocated by the author. He mentioned that the indices could be handled by data-processing machines used in trend-surface analysis. The present paper shows the value of Q1MdQ3 indices for presentation of the regional distribution of grain size on maps (figs. 1-3).
Sedimentary geology of the Holocene in lake IJssel region1971Ente, P.J.50(3)Topics of the Holocene sedimentary geology based upon detailed investigations in the third polder of the Zuyderzee project are presented. They comprise distribution, composition and dating of sediments of the Calais-transgression phases, strongly bound to the evolution of the western Netherlands. Mainly after the first Duinkerke-transgression phase the development evolves towards a separate history of the Zuyderzee. Its evolution from a complex of lakes towards a brackish-saline lagoon is shown by the described sediments of different composition. The development of the delta of the river lJssel is brought into relation with that of the lagoon. The displacement of sands along the coast by wind/wave effects is shown, together with the phenomenon of numerous megaripples present at. the edges of the sand masses.
Prograding clastic fans and transition from a fluviatile to a marine environment in Neogene deposits of Eastern Crete1971Gradstein, F.M.; Gelder, A. van50(3)In Neogene deposits of the eastern Sitia district (eastern Crete), a lateral succession from fluviatile to marine deposits has been reconstructed. Paleocurrent analysis indicates mainly southwest-directed sediment transport. The reddish deposits in the east (Kastti Formation) display braided-river characteristics. The fluviomarine deposits in the central part of the area (Toplou Formation), lie laterally of the braided-river deposits eastward. The fluviomarine deposits include thick conglomerate sheets, which display giant foresetting in sets between 5 and 30 m. high. This giant foresetting probably reflects the depositional slopes of large fans built by the discharging river below sea level. The submarine nature of deposition is confirmed by Ostrea between or on the pebbles. In the extreme southwestern part of the area marine marls occur (Akhladia Formation) with clastic intercalations, which bear evidence of mass transport, and which probably have been derived from the discharging river courses northeastward. Uniserial Uvigerina and Globorotalia in these marine marls point to a Late Miocene age of these deposits and hence of the fluviomarine and the fluviatile sediments.
Contents and behaviour of Mercury as compared with othe heavy metals in sediments from the rivers Rhine and Ems1971Groot, A.J. de; Goeij, J.J.M. de; Zegers, C.50(3)Mercury is one of the various waste substances transported by the river Rhine across the German-Dutch border. Together with a number of other heavy metals mercury is present in large quantities. Upstream these metals are predominantly fixed to the suspended solids in the water and may be deposited on river flats and flood plains. From the fresh-water tidal area of the river onward, however, these elements are more or less solubilized during their transport as organo-metallic complexes. The mobilization of mercury is most pronounced in this respect. Leading to more normal amounts of this element in sediments from the Wadden Sea. This article deals with the behaviour of mercury through the whole Rhine estuary as compared with a number of other heavy metals. As a counterpart of the Rhine the same processes ale described for the river Ems. The latter may be regarded as a classic example of an unpolluted stream.
Molasse and clastic-wedge sediments of the Southern Cantabrian Mountains (NW Spain) as geomorphol;ogical and environmental indicators1971Jong, J.D. de50(3)Post-orogenic sediments supplied by the Cantabrian Mountains during successive stages of uplift, were of the molasse type during the Stephanian and later of the clastic-wedge type. Sedimentological research has provided information on the source area and the environmental and climatic conditions under which these generally coarse grained sediments were deposited: warm and humid for Upper Carboniferous, warm and relatively arid for Triassic and Tertiary times. The depositional environments were in all cases torrential, alluvial fans grading into flood plains with finer grained sediments.
Depositional environment and weathering phenomena of the white Miocene sands of Southern Limburg (The Netherlands)1971Jong, J.D. de; Waals, L. van der50(3)White Miocene sands occur in a block-faulted area near the southern limitation of the marine Miocene deposits in The Netherlands. Sedimentary structures, granulometric parameters, and the occurrence of fossil shells and burrows, point to shallow-marine tidal and littoral depositional environments. The mode of occurrence of silicifications in sand and lignite, the occurrence of red-yellow podzolic soils, and the absence of any unstable components among the heavy minerals point to a post-depositional strong chemical weathering in Tertiary times. The white colour of the sands should not be considered as an effect of bleaching by the lignites.
The effects of selective erosion by overland flow on the ice-pushed ridges of Uelsen (County Bentheim, Germany)1971Jungerius, P.D.; Wiggers, A.J.50(3)The surface of the ice-pushed ridges of Uelsen is marked by parallel ridges of Pleistocene material rich in gravel' and intervening depressions in gravel-free Pleistocene and Tertiary deposits. This relief results from selective erosion by runoff in a humid temperate or a nivation climate. Later periglacial conditions with solifluction and wind action disrupted the drainage system and suppressed the relief. Present geomorphic processes tend to diminish the effects of the periglacial environment.
Tentative data on flow resistance in suspension currents1971Kuenen, P.H.50(3)The efficiency with which turbidity currents have carried large volumes of sand for great distances on slight slopes of the deep-sea floor is remarkable. This seems to argue against high flow resistance by 'Jostle" viscosity and floor impacting. The grading of the deposits is inexplicable by thin, dilute currents because these would have to be fed at the origin over a period of a dozen hours or longer, to supply the observed volume of larger beds, and with decreasing grain size. High densities (over 1.16) seem more probable than great thicknesses (over 100 m). Experiments on viscosity of suspensions showed moderate values up to densities of 1.2 for clay and 1.5 for mainly sandy mixtures. Eddies large in comparison with the grain size do not meet serious obstruction by jostling. Measurements in a circular flume of bottom drag for suspension currents indicate that resistance is less than for clear water on a cohesive rough bottom of the same grain size and less than 2 X that of clear water on a smooth hard floor. These results, although of a tentative nature and without refinement by considerations of scale or of the paddle turbulence, appear to show that densities over 1.16 up to 1.5 as deduced from velocity cum thickness of the currents and from grading in the turbidites, ale not contradicted by flow resistance. True experimental turbidity currents are being studied to gain further insight.
Transition from fluviatile to tidal-marine sediments in the Upper Devonian of Seven Heads Peninsula (South County Cork, Ireland)1971Kuijpers, E.P.50(3)Along the east coast of Seven Heads peninsula (southern Ireland) a more than 1000m thick north dipping succession of Upper Devonian strata is investigated. The lithology and sedimentary structures of the facies types are described and briefly compared with recent sediments. They indicate a gradual transition from a continental "Old Red Sandstone" facies along a coastal plain facies into overlying (tidal) marine facies.
Recent marine limestones from the shelf off tropical Brazil1971Mabesoone, J.M.50(3)Samples of recent limestones and calcareous sandstones dredged from the continental shelf off northern and northeastern Brazil have been studied. Three types of rock can be distinguished: (1) calcarenites composed of many organisms and fragments, classified as biomicrites in thin section; (2) algal accretionary limestones, showing almost entirely algal structures, named algal biomicrites; (3) calcareous sandstones, lime-cemented shelf sands of fluvial origin. Besides these, one sample was collected from the continental slope, determined as a foraminiferal intrabiosparite. Study of fauna and mineralogical composition revealed a recent age for all types, confirmed by the faunal assemblage and the dominance of aragonite and high-Mg calcite. The lithification of calcarenites and calcareous sandstones occurred by cementation of the loose bottom sediment under favourable conditions, in a marine open shelf environment, up to depths of about 100 m. The algal limestones are growth structures of calcareous algae, chiefly Lithothamnium.
The quaternary geology of the southern area of the Dutch part of the North Sea1971Oele, E.50(3)A map of the southern area of the Dutch part of the North Sea is presented. The geological history of the Quaternary can be summarized as follows. During the Late Tertiary and Early Pleistocene sedimentation of fìne sands and clays took place in a marine environment. Gradually the westwards progradation of the "Rhine-Meuse" delta caused these sediments to be covered by a veneer of fluviatile sediments of about the same grain size. In the Middle Pleistocene the sediments became coarser, but were still of fluviatile origin. Meltwater clay of the Elsterian glaciation, present in the north, marks the first observed interruption of the fluviatile sequence. After the Holsteinian interglacial, the Saalian glaciation reshaped the topography, creating ice-pushed and morainic ridges. During the Eemian interglacial a marine environment persisted, whilst the marine sedimentary series was closed by the deposition of a fresh water clay in the Early Weichselian. 3) Later during this cold phase the coversands were formed in the north, the Kreftenheye Formation being deposited by the Rhine in the south. The Holocene sea level rise resulted in the deposition of the Lower Peat Bed and a cover of tidal flat sands on top of which, after a period of non-deposition, the young seasand was deposited.
The quaternary geology of the southern area of the Dutch part of the North Sea1971Oele, E.50(3)Large Enclosure
The frequency distribution of the current speed at the Netherlands lightvessels and its possible influence on the composition of sediments in the Southern North Sea1971Otto, L.50(3)Frequency distributions of current velocities were determined from the Netherlands lightvessels in the North Sea. Near the lightvessel "Texel" the frequency distribution shows a considerable degree of symmetry. By means of a simple model for transport of sediment the consequences of such a frequency distribution for the transport of particles of different sizes are investigated. There appears to be a distinct maximum in the transporting velocity near the lightvessel "Texel" for a certain particle size. This particle size is estimated to be about 300 μ, a value that corresponds with a relative poverty of particles between 200μ and 300μ "downstream" of the position of the lightvessel.
Tidal deposits and their sedimentary structures (Seven examples from Western Europe)1971Raaf, J.F.M. de; Boersma, J.R.50(3)Seven examples of tidal sedimentation ranging between modern and Devonian age are illustrated and briefly discussed. They cover known (modern intertidal and subtidal) and mostly undetermined ancient tidal subenvironments, and have been taken from: 1. The estuarine reach of a tidal river, subtidal, Holocene, Barendrecht excavation, The Netherlands. 2. An estuarine channel, subtidal, Holocene, Haringvliet excavation, The Netherlands. 3. A Lower Pleistocene (Tiglian), possibly subtidal estuarine succession, Hattem (Veluwe), The Netherlands. 4. A dune-bearing estuarine sand-bank, intertidal, modern Western Scheldt, The Netherlands. 5. The Lower Cretaceous (Lower Greensand) Woburn sands ± 50 km NW of London, England, being probably deposited in an open marine tidal environment. 6. The Oligocene (Tongrian) Kerkom- and Neerrepen sands SE of Brussels, Belgium, representing an as yet uncertain type of tidal subenvironment. 7. An Upper Devonian tidal succession belonging to the transgressive complex (Cork beds) overlying the Old Red, W. of Cork, Eire. The following features were considered to be diagnostic for these (and other?) tidal deposits (a) vectorial bimodality of the cross-stratification, (b) common joint occurrence at different proportions of largescale and smallscale structured units in super- of juxtaposition. (c) Usually poorly developed sequential regularity with occasional occurrence of fining upward sequences. (d) Unidirectional cross-stratified sets displaying several kinds of features resulting from the intermittent and bidirectional character of the currents (discontinuity planes). (e) Fairly common occurrence of flaser- and/or lenticular bedding respectively consanguineous mud-sand interlaminations in smallscale-structured units. (f) Slight to intense bioturbation in several types of sandy and/or muddy units. At the present state of knowledge a reliable determination of the tidal sub-environment (e.g inshore, offshore, intertidal, subtidal) seems to be virtually impossible for ancient clastic deposits, except for a few cases. Establishment of detailed paleocurrent patterns may help in distinguishing open-sea tidal deposits from inshore ones.
A contribution to the sedimentary-petrological description of the Maas deposits in Southern Limburg (The Netherlands)1971Riezebos, P.A.50(3)From the Plio-Pleistocene series of sediments deposited by the river Maas on the Late Tertiary peneplain of southern Limburg.(The Netherlands) three samples, one of Pliocene and two of Pleistocene age have been taken. From these samples the grains between 500 and 2 micron have been subjected to microscopic investigations. The acquired mineralogical data confirming in broad outline previous investigations, reveal that the Pleistocene materials deviate from the Pliocene especially on account of a very great content of goethite particles. It is suggested that the great amount of goethite may be of use to discern the Quaternary Maas deposits from other contemporary fluviatile sediments.
Litho-facies of inshore estuarine and tidal-inlet deposits1971Terwindt, J.H.J.50(3)Three litho-facies may be distinguished in inshore estuarine and tidal-inlet deposits. In general these litho-facies are related to the intensity of the current action over the bottom. The current action shows rapid variations in time due to alternating spring and neap tides and/or wind influences and to shifts of the channel axis. As a result fining and coarsening upward sequences of the sediment types are found. The frequency of occurrence of the litho-facies varied with depth in the estuary studied, but not in the tidal inlets.
Depositional environments of the Eocene Mirador and Misoa Formations Maracaibo Basin, Venezuela1971Veen, F.R. van50(3)Outcrops and cored sections of the Lower-Middle Eocene Mirador and Misoa formations in and around Lake Maracaibo have been analysed sedimentologically and palacontologically in order to establish depositional environments. Three genetically distinct sandstone units could be recognised: the fluviatile point bar, the deltaic distributary channel-fill and the offshore bar or barrier beach. Each of these units is characterised by a specific vertical grain-size trend and sequence of bedding types. A fluviatile environment is typical for the Mirador Formation, whereas deltaic plain and delta-fringe environments obtained during deposition of the Misoa. The Misoa constitutes overall a transgressive sequence interrupted by several phases of delta-building which become less important upwards. The Mirador and Misoa sediments are thought to form parts of one alluvial deltaic complex of Mississippi size. A deltaic source for the basinal turbidites of the Trujillo Formation, which is the lateral equivalent of the lower part of the Misoa, is likely. The Misoa grades vertically and laterally into the holo-marine shales of the Pauji Formation.
Directional trends in Dutch coversands1971Veenstra, H.J.; Winkelmolen, A.M.50(3)The article presents a general survey of the coversands in The Netherlands and northern Belgium. About 50 samples were taken mainly in a N-S run and in 15 localities oriented cores were taken with plexiglas tubes. Of all the samples a grain-size analysis was made by sieving and all the sieve fractions were tested for rollability, a functional shape parameter. After impregnation, the cores were inspected with X-rays and the directions of the oblique bedding planes measured. Of selected parts thin-sections were cut and the grain orientation was measured under a microscope. The directional features of foreset dips and fabric anisotropy both pointed towards transport from mainly northern directions. Also the grain-size and shape-sorting studies revealed a N-S trend. This trend, however, was not continuous but showed a repetition south of the rivers Rhine and Meuse. The coversands showed strong receiving shape characteristics and the coarser grains are of low sphericity. Although the infiuence of local sources is probable, the impression was gained that the main source of the Dutch coversands must be looked for in the region north and northwest to Holland, in the present North Sea. This fits well with the former observation of the pronounced sphericity of the sands in this area, which is explained as a lag characteristic obtained during the blowing out of the coversands.
Sedimentological aspects of oil fields in the Niger Delta1971Weber, K.J.50(3)One of the most conspicuous geological features of the Niger Delta is its growth fault pattern. Almost all the oil reserves are contained in rollover structures which are associated with growth faults. These structural features are thought to have been formed by the force of gravity acting on a thick body of sediments supplied mainly by the Niger River. These sediments form a typical deltaic offlap sequence consisting of a wedge of continental sands grading downwards into marine clayey sediments which, at a greater depth, are in a state of undercompaction. Stratigraphically most of the known oil accumulations occur in the paratic sequence, i.e. the transition zone between the continental and fully marine sediments. The paralic sequence consists of a large number of sedimentary offlap cycles, each cycle starting with a marine clay, generally less than 150 feet thick and changing upwards progressively into proximal fluviomarine interlaminated silt, sand and clay which are usually followed by various types of more sandy barrier-bar and coastal-plain deposits. The cycles are terminated by transgressions which erode away part of the offlap sequence and which are generally represented by a thin, very fossiliferous gravelly sand. In this paper the relationship between sedimentation and growth faults is discussed. Examples are given of depositional cycles and of the associated types of reservoir rock. Attention is given to the influence of the depositional environment on the petrophysical properties of the rock, reservoir continuity and reservoir imhomogeneities.
De huidige problematiek omtrent investering door of met het buitenlands bedrijfsleven in mijnbouwkundige objecten in ontwikkelingslanden1971Stikker, D.U.50(4)
Isotopic dating in the Kamativi Tin Belt, Southern Rhodesia1971Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verdurmen, E.A.T.; Verschure, R.H.50(4)Rb-Sr measurements point to an Eburnian age (around 2150 million years) for the granites and tourmaline pegmatites in the Kamativi area, southern Rhodesia. From Rb-Sr and K-Ar mineral dates it is evident that a tectonothermal event affected the area in Kibaran time, about 970 million years ago; the emplacement of the tin-bearing pegmatites was probably connected with this event
Eustatic drop of two meters since babylonian times?1971Vanderzee, T.J.50(4)
KNGMG Jaarverlag 1970197150(4)
A new find of the ichnofossil Phagophytichnus Ekowskii van Amerom1971Amerom, H.W.J. van; Boersma, M.50(5)The ichnofossil Phagophytichnus ekowskii Van Amerom, known to occur in the Upper Carboniferous of Spain and in the Permo-Carboniferous of South Africa, is described for the first time from the Westphalian C of Northern France
Current vector dispersion in a river of fluctuating discharge1971Collinson, J.D.50(5)As water stage falls over a bedform covered sediment surface, local flow directions are increasingly controlled by the topography and if the bed material is still mobile, smaller surface features will reflect the control. Dispersion will increase as water stage falls. A bank in the bed of the Tana River, Norway, is used to illustrate this. Pebble features record high stage directions while sand features reflect falling stage modifications in direction of flow. Consideration of this effect might be important in using palaeocurrent distributions to specify channel type in fluviatile sandstones.
Buried tunnel valleys off the Northumberland coast, Western North Sea1971Dingle, R.V.50(5)A series of deep, steep-sided, probably linear erosion hollows is described from the East Bank area on the northwestern side of the Dogger Bank, off the Northumberland coast of England. These hollows are infilled with bedded sediments and the whole sequence overlain by thick surface sediments with large linear banks. It is concluded, after a comparison with similar features from the western North Sea, that the East Bank hollows are buried tunnel valleys, which were excavated by sub-glacial streams near the edge of the Weichsel ice sheet, which deposited the Dogger Bank terminal moraine.
Late Cretaceous age based on K/Ar dates of granitic rock from the Tambelan and Bunguran islands, Sunda Shelf, Indonesia1971Haile, N.S.; Bignell, J.D.50(5)K/Ar determination on two adamellites from the Tambelan and Bunguran Islands, on the Sunda Shelf between the Malay Peninsula and Borneo, indicate that these are pre-Tertiary, probably Late Cretaceous' Rb-Sr determinations on the rock from Bunguran Island' and a third granitic rock from Tambelan Island, are not definitive, but are consistent with a Late Cretaceous age for the intrusion of the granitic rocks. These determinations, the first age indications from the Tambelan and Bunguran Islands, throw doubt on the supposed "pre-Upper Triassic" age of the acid batholiths in the Anambas Zone of the Sunda Shelf and its extension into West Borneo.
Stratigraphic position of the limestones and conglomerates around the Marimana granodiorite, Central Pyrenees, Spain1971Hartevelt, J.J.A.50(5)Limestones bounding the Marimaña granodiorite, in the Central Pyrenees, which have until recently been correlated with the Cambro-Ordovician 'Calcaire métallifère" or "Calcaire de Bentaillou", have been proved to be of Devonian age. Conglomerates occurring at some distance below should be correlated with the main conglomerate level of the Cambro- Ordovician of the Pyrenees.
The Holocene eustatic sea level problem1971Mörner, N.A.50(5)
Postglacial changes in level of land and sea1971Ward, W.T.50(5)Four postglacial high sea levels, separated by intervals of low water, are recognized at 7.5 ft, 4,5 ft, 3.0 ft and 1 ft above present mean sea level in East Gippsland, Victoria, Australia. Direct estimation of shoreline age is made impracticable by an absence of datable material in the stranded beach sediments, but a few dates are available for lagoonal beds. These dates, and correlations with New Zealand made possible by the common occurrence of similar sequences of coastal dunes resulting from changes in postglacial climate, suggest that the four stages of high sea level occurred about 4,700, 3,000, 1,500 and 750 calendar years ago. In particular the East Gippsland shoreline sequence is similar to that observed in the Firth of Thames, New Zealand. The stranded shorelines are believed to result from combination of long-term land uplift with real changes in sea level. This conclusion follows comparison of the Firth of Thames data with observations reported for 15 other localities in New Zealand, western Europe, North America, Africa and Oceania. Contradictory theses concerning postglacial sea-level changes in these localities are reconciled if it is assumed that each locality has been affected by earth movements. Such movements are already recognized in some areas affected by isostatic rebound or by mountain-building, and are presumed in other where shorelines appear excessively high or excessively low. To facilitate comparison, two simple models that relate shoreline elevation to implied rate of uplift are used. These models are based on the supposition that the earth movements actually experienced were continuous, or can be reasonably represented as small fluctuations about a regular long-term trend. It is not yet possible to decide whether any of the localities studied has been stable in postglacial time. Earth movements may not have affected the Cook Islands, South Pacific, however. If this is so, it would seem that the sea g:ained its present level several thousand years ago. Subsequent fluctuations have been in response to global climatic changes. The highest level actually attained by the sea (5.5 ft) was reached briefly in Sub-boreal time.
A three dimentional vector method as an aid to continuous-dipmeter interpretation1971Nederlof, M.H.; Weber, K.J.50(6)Means of dipmeter readings derived by a three dimensional vector method have proven to be useful in deriving structural dip and azimuth from a collection of widely scattered dips. A computer program to calculate 3-D vector means and related statistics has been developed. Dip distributions are comparable to the spherical normal distribution so that for practical purposes a measure of reliability of the vector means can be calculated. The 95% confidence cone around the vector mean is chosen as the most convenient yard-stick. Confidence angles for the mean dip angle and mean azimuth are derived separately from this confidence cone. Preferably, study and correlation of well logs should precede the averaging procedure. This enables the selection of intervals, which contain readings mote-or-less conforming to the structural dip and azimuth. The calculated average dips can be displayed on a tadpole plot, or other plots against depth. The average dips are much easier to interpret than the original data, especially when using a condensed depth scale. The difference between successive vector means is a measure of the rate of change of dip with depth and can reveal the presence of discontinuities, such as faults and unconformities which might otherwise remain undetected in the "raw" data. The approach is applicable to both 3-arm dipmeter logs and the mote modern 4-arm dipmeter logs for which the digitized curves are correlated by the computer.
Tubular fossils in the bauxites and the underlying sediments of Surinam and Guyana1971Valeton, I.50(6)This paper presents a description of the possible plant fossils and burrows in the bauxite belt which extends through Surinam and Guyana. The possible plant fossils are defined as roots, treetrunks, and branches forming horizontal layers of roots in the underlying sediments and the basal part of the bauxites. The plant fossils show external textures, and internal structures which may be taken to be cuticulae. Within the bauxites burrows of various diameters may be seen. Internally, they either show the typical "Stopfgefüge" or lack structure entirely. The presence of plant roots and burrows proves that a large proportion of the bauxite in the bauxite belts of Surinam and Guyana originates from sediments formed in either a mangrove environment, a fresh-water marsh environment, or a brackish swamp environment.
Overconsolidation in some fine-grained sediments; its nature, genesis and value in interpreting the history of certain English Quaternary deposits1971Greensmith, J.T.; Tucker, E.V.50(6)Soil mechanics parameters, such as apparent cohesion, natural moisture content and liquid limit, are useful additional factors in determining depositional and erosional events within non- and partially-lithified sedimentary successions. Overconsolidated beds, caused by desiccation, occur in the marine Quaternary succession of the Essex coast and they indicate at least two important periods of prolonged desiccation during lowered sea levels. The older phase reflects, in part, the late- Devensian - Holocene (Flandrian) interIude of depressed base-level and extended over at least 10,000 years. The younger and shorter phase is intra-Holocene c. 4,500 B.P.
Radiometric evidence for a Precambrian metamorphic event in N.W. Spain1971Vogel, D.E.; Abdel-Monem, A.A.50(6)
Solifluction and colluviation on the ice-pushed ridges of Uelsen, Kreis Grafschaft Bentheim, Germany1971Bos, R.H.G.; Jungerius, P.D.; Wiggers, A.J.50(6)The erosional history of the ice-pushed ridges of Uelsen is reflected in correlative slope deposits. Würmian processes lowered the gravelly summits of the hills and produced the characteristically unsorted solifluction deposits. These include remnants of an Eemian (?) soil. In contrast, Holocene erosion only affected the fine-grained soils on the flanks of the hills. It acted so slowly that well-developed humus podzols could be preserved on the eroded slopes, as well as on sites of colluvial deposition. The colluvium is strongly sorted because many small mineral grains were transported in humic aggregates of modal size.
Brief account of the symposium on geochemical exploration in Delft - March 5th, 19711971Botman, A.C.50(6)
Present status and future prospects in exploration geochemistry1971Webb, J.S.50(6)
Global distribution of tin abundances1971Oosterom, M.G.; Schuiling, R.D.50(6)
The regional geochemical landscape of the Moresnet metallogenic district1971Dijkstra, S.50(6)
Geochemical patterns and structural alignments in relation to antimony-mercury-tungsten mineralisations in the Nidge area, Turkey1971Kleyn, P.H. van der50(6)
Use of mercury in geochemical exploration1971Friedrich, G.50(6)
Application of automatic data processing to problems of exploration geochemistry1971Bosman, E.R.; Eckhart, D.; Kubik, K.50(6)
Geobotanical exploration1971Cole, M.M.50(6)
Marine geochemical exploration1971Tooms, J.S.50(6)
Indrukken van het IMA-IAGOD congres, Tokio-Kyoto 19701971Uytenbogaardt, W.50(6)
Review of geohydrological activities in the Netherlands since World War II, in particular of the government institute for water supply1972Romijn, E.51(1)Geohydrological activities in The Netherlands have undergone some remarkable developments since World War II. Besides the Government Institute for Water Supply many other agencies and institutes have contributed to this progress. Scientific achievements in geohydrology have largely run parallel with the rapid social and economic development of the Netherlands since the war.
Hydrogeological maps of the Netherlands1972Jelgersma, S.; Visser, W.A.51(1)Two hydrogeological maps, in scale 1 : 1,500,000, have been compiled, based on the principles laid down for the International Hydrogeological Map of Europe. Map I is representative for shallow conditions; map II is representative for the sequence of sediments ranging from Pliocene to Holocene.
Hydrogeological maps of the Netherlands1972Jelgersma, S.; Visser, W.A.51(1)Large Enclosure
Geohydrological investigations with a view to groundwater catchment, a case history1972Damme, J.M.G. van51(1)With the intention to give an impression of the usually applied geohydrological procedures for the foundation of a pumping station in the Netherlands, the investigations for the well field at Beerschoten (provincie of Utrecht, The Netherlands) are reviewed. The area concerned is located on the western slope of ice pushed hills forming the Utrecht Ridge. The subsoil consists predominantly of Pleistocene sandy deposits of fluviatile origin, with local loam layers. The groundwater has a suitable quality for the preparation of drinking water and requires only a simple treatment. From a pumping test it appeared that the studied area is situated in the transition zone between a recharge and a discharge area and that loam layers delay the propagation of drawdowns from the pumped aquifer to the phreatic surface. The transmissivity of the aquifer from which the water will be withdrawn amounts to 3500 m2/day. On the base of subsequent studies carried out by means of a mathematical method and electrical model tests a prediction of the consequences of the withdrawal for the groundwater table has been given. Several relatively simple statistical methods are described, from which it appears that in spite of a certain lack of appropriate data. The prediction given was reasonably reliable and also that after adjustments for several external influences the actual consequences of the withdrawal could be very well determined. As in many other cases, the practical sustained yield in this area depends merely on the drawdowns due to the withdrawal and on the decrease of underground flow to ditches. From the point of view of water resources management the survey forms an example of a case where a series of multi-purpose investigations should serve to arrive at an optimum exploitation of the groundwater.
Fresh water winning and salt water encroachment in the Amsterdam dune water catchment area1972Roebert, A.J.51(1)In the Amsterdam dune-water catchment area, a freshwater lens of some 40 to 90 m thickness is resting on salt water in the lower aquifer, located at a depth of 20 m to 160 m - O.D. Waterextraction from the lower aquifer has disturbed the fresh-water/salt-water interface, extending it into a zone of dispersed, brackish water. For many years, the extraction area has been overdrawn. This article will discuss salinity conditions in the Amsterdam catchment area, and draw up a comparison between its current stock of fresh water and the original volume present before the start of waterwinning in the area. With the introduction, in 1957, of artificial recharge through infiltration of Rhine-water into the upper aquifer above 15 m - O.D., water extraction from the lower aquifer, which had been hampered by increasing salt-water contamination of the wells owing to the upconing of brackish water, was virtually stopped. The lower aquifer, however, still holds a vast stock of fresh water, which, if developed by a system of intermittent extraction, could substantially contribute to the water supply of the greater Amsterdam area.
Fresh water winning and salt water encroachment in the Amsterdam dune water catchment area1972Roebert, A.J.51(1)Large Enclosure
Buried channel aquifers and present open drainage system of East Gelderland, the Netherlands1972Vries, J.J. de; Rees Vellinga, E. van 51(1)In the eastern part of the province of Gelderland, two buried valley systems have been traced. One system is filled with fluvioglacial deposits dating from the Saalian Ice Age, the other with preglacial fluvial sediments which are remarkable rich in vulcanic minerals. Both systems have a course which is almost perpendicular to the present drainage system. This change in stream direction is explained by postglacial replacement of the main drainage channel in the area, tectonic movement perpendicular to the old channels, and postglacial filling of the old channels with wind blown sand.
Permeability distribution in a holocene distributary channel-fill near Leerdam, (The Netherlands)1972Weber, K.J.; Eijpe, R.; Leijnse, D.; Moens, C.51(1)In order to understand and predict the production performance of a reservoir it may be important to know its permeability distribution in detail. The internal structure of Iayered sand bodies, such as those that result from the deposition of sands in channels, could for instance cause an overall permeability anisotropy. We have developed a method of deriving the permeability distribution in such a sand body from measurements on core samples. This method has been checked by comparing the permeability distribution deduced from measurements on samples from an actual channel-fill with that derived from flow tests in the same sand body. Our experimental data on unconsolidated distributary channel-fills show that permeability anisotropy is negligible in such sand bodies.
Contribution to the geochemistry of groundwater in Northern Germany1972Löhnert, E.P.51(1)Moderately saline groundwaters, which are still usable for drinking and industrial purposes, occur in Northern Germany until depths of approximately 500 meters below the surface. Apart from local saline water intrusions along the North Sea coast and rivers, the saline components of groundwater are derived from deep groundwaters, which can be related to salt bodies mainly of Zechstein age. Sulfate waters are found in the immediate vicinity of salt domes. In contrast chloride salt waters and brines are also found further away from the salt bodies, and show indications of reduction and base-exchange. The relationships of the groundwater types toward each other should be clarified by means of isotope research. A chemical classification of groundwater has been proposed, which bears in mind the absolute as well as the relative contents of main ions (fig. 2).
The use of geohydrology in solving water management problems in agriculture1972Wesseling, J.; Colenbrander, H.J.51(1)For the study of water management problems in agriculture often the same hydrologic parameters and calculation techniques are applicable as for civil engineering studies (e.g. foundations) and drinkwater supply studies (e.g. extraction and recharge of water). Therefore, arbitrary subdivision of hydrology as agro-hydrology, geohydrology etc. does not always make much sense. In this paper the use of some hydrologic calculation techniques in solving water management problems in agriculture is elucidated.
Application of models in geohydrological investigations1972Ouwerkerk, J.H. van; Zeilmaker, D.A.51(1)The application of models in geohydrological investigations is closely related to the use of quantitative methods in groundwater hydrology. To help determine which type of model should be chosen an analysis of the following aspects is required: nature of the problems, structure of the hydrological system, types of models and general conditions. The large number of factors involved in this analysis, and the small number of results of alternative methods of investigations, preclude the formulation of a generally applicable rule of selecting a model.
The use of computers in water resources development and water supply planning1972Ridder, N.A. de51(1)There is an urgent need for a new approach and the application of modern techniques in solving the problems of future water supply. More than is the case at present, proper planning must relate the physical, environmental, economical and social factors involved. But integration of the various elements encounters some major difficulties of which insufficient data and lack of an exact and comprehensive methodology are the most serious. In the last few years there have been a series of important developments in, total water resources management methods and water supply optimization techniques. Basic to these developments in total water resources management methods ciplines as Operations-Research and Systems Analysis, and the availability of high-speed electronic computers. Planning techniques based on the computer's ability to process vast amounts of information enables the engineer to check a certain solution by arbitrary variation of the given or assumed parameters of his model. The water demands of an area can be met either by delivering surface water, or groundwater, or by an almost infinite number of possible combinations of these two resources. But water should be supplied economically without causing harmful effects within the area or its surroundings. To achieve this objective the technique of linear programming can be applied, as it allows to find for each plan an optimum solution of water supply under the given constraints. Then, using a digital computer model of the groundwater basin, which is capable of simulating the extraction and replenishment flows, the consequences of future water engineering works can be determined. The unique feature of these two models is that the output of the linear programming model can be used directly on the groundwater basin model to test the physical validity of the economic solution.
Recent developments of physical investigations in boreholes and wells1972Walter, F.51(1)Well logging methods and physical borehole investigations have come into use for geohydrological reconnaissance in The NetherIands in recent years. In open uncased boreholes the following features are logged: spontaneous potential, resistivity, natural gamma radiation and diameter; interpretation methods are given in short. Reference is made to investigation methods in observation and discharging wells. Permanent electrode systems can be used for monitoring ground-water salinity.
Application of natural isotopes in ground water hydrology1972Mook, W.G.51(1)18O, deuterium and tritium may serve as tracers and be used to determine the origin of groundwater. The radioactive isotopes 14C and T can be used to date water. Deuterium and 13C may give information about evaporation and processes in the unsaturated zone
An electronic groundwater-level detector with automatic output registration1972Rijn, W.P. van51(1)A simple, robust, electronic groundwater-level detector has been constructed which measures the water level in piezometers with an accuracy of better than ± 1mm. A series of these instruments can be connected to an automatic digital recording system. Measurements can be performed according to a selected programme of measuring times. The reference level at each level-detector location is indicated by gauging glasses attached to a system of interconnected liquid-filled tubes.
KNGMG Ledenvergadering 1971197251(1)
Aan de leden1972Krol, G.L.51(1)
Preface Special Issue "Geohydrology - Hydrology"1972Smoor, P.B.51(1)
Aan de leden1972Krol, G.L.51(2)
Zestig jaren KNGMG1972Brueren, J.W.R.51(2)
Complete lijst van de verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig genootschap1972Helleman, G.51(2)
Preface special issue "Zambia"1972Mulaisho, D.C.51(3)
Introduction Special Issue "Zambia"1972Vletter, D.R. de; Dijkstra, S.; Bruggen, J.W. ter51(3)
Zambia's mineral industry and its position amongst world's major copper producers1972Vletter, D.R. de51(3)Tonnages and values of the chief minerals at present mined in Zambia are included in a survey which also touches on other mineral resources, e.g, nickel. Zambia's position amongst other major copper producers is described in terms of production, average grades mined, ore reserves and costs. Estimates of copper production for the next few years are given and some events affecting the copper industry in the past decade considered, especially as they relate to the position of the developing vis à vis the developed countries. The extent to which copper dominates Zambia's economy is noted and its contribution to the Gross Domestic Product, to exports, Government revenues and employment is compared with that of its sister industries in the CIPEC countries (namely Chile, Peru and Zaire). The corporate structure of Zambia's copper mining industry is described and the terms of the agreement by which the Government of Zambia acquired a 51 per cent interest in the industry in 1970 are set out. Important implications of recent mining legislation including the Mineral Tax Act 1970 and the Income Tax (Amendment) Act,1970, are also considered.
Outline of the geology of Zambia1972Drysdall, A.R.; Johnson, R.L.; Moore, T.A.; Thieme, J.G.51(3)The structural-stratigraphic provinces of Zambia are described with special reference to recent work by the Geo logical Survey. The Tumbide and lrumide deformations are redefined as episodes of the Kibaran Orogeny, and attention is drawn to Kibaran foreland folding within the Bangweulu Block. The Lufilian Arc is shown to be a polyphase structure, and is contrasted with the Mozambique Belt which is believed to be polyorogenic. The continental Karroo sediments preserved in the partly fault-bounded, riftlike structures of the mid-Zambezi, Luangwa and Kafue troughs are briefly described. The presence of Cretaceous beds in Western Zambia and a marine horizon beneath the continental succession are noted.
Outline of the geology of Zambia1972Drysdall, A.R.; Johnson, R.L.; Moore, T.A.; Thieme, J.G.51(3)Large Enclosure
Sedimentary environment of Zambian copper deposition1972Garlick, W.G.51(3)Superseding of the hydrothermal origin by syngenesis subsequent to 1928 is recorded historically. Granites claimed to be intrusive were in 1940 found to be overlain unconformably by Katanga sediments. The bulging intrusive granites became bulging paleo-hills, avoided by copper mineralization. Discovery that ore grade in the deformed and shattered orebeds of a dragfold was no richer than in the unfolded sections, proved that the mineralization was prefolding. Two decades later dolomitic facies over some granite bulges proved to be algal bioherms. By the syngenetic theory the zonal sequence, from copper-rich to iron-rich sulphide, was interpreted as representing depth zones parallel to shoreline controlled by the activity of anaerobic bacteria. Recognition of anhydrite explained mysterious cavities in veins, conditions of sedimentation, and the source of the sulphur to form the sulphides and, by its solubility, explained the high porosity of the Katanga sediments to depths of 600 m. Features of the ore shale deposits such as dissemination instead of selective replacement, mineral zoning, association with basins flanking paleo-hills, barren gaps over bioherms, apply also to mineralization in arenites. Pyritic disseminations in sediments over granite hills and sulphide concretions are confined to orebodies in arenite, explainable by its greater original permeability. Evidence for syngenesis derives from interpretation of the depositional environment, although many of the processes are still being elucidated. Prior to formation of the major ore deposits, in marine waters, evaporation of playa lakes gave high concentrations of sulphates, borates, and, under anoxic conditions, sulphide precipitation. Drying out of such lakes exposed mud flats on which efflorescences of gypsum, borates, and iron and cobalt sulphates presumably formed. Wind erosion at Mufulira produced dunes containing high proportions of gypsum later converted to anhydrite. At Chibuluma floods dissolved iron and cobalt sulphate from desiccated mud flats and on entering the saline lake precipitated hydroxides of these two metals as a heavy red mud with suspended sand grains and pebbles. The hydroxides were then converted to sulphide, whilst copper and iron were precipitated as sulphide in the overlying waters. Borates diffused into the underlying sand and combined with muddy coatings and matrix of the sand grains, to form tourmaline. Copper and cobalt were precipitated in greatest quantity at convergence of currents in the playa. Sulphide in sediment became sufficiently indurated to be eroded and redeposited as detrital grains, concentrated on foresets and truncation planes with tourmaline, sphene, epidote, and zircon grains. Compaction folding over Basement hills and even over biohermal and aeolian accumulations were controls for ore deposition.
Coppper orebodies in the basal lower Roan meta-sediments of the Chingola open pit area Zambian Copperbelt1972Voet, H.W.; Freeman, P.V.51(3)Lenticular copper concentrations in basal atenaceous and rudaceous members of the Katanga System occur in basins in Basement gneiss and schist in an area of rugged palaeotopography at the Chingola Open Pit sector of Nchanga Mine on the Zambían Copperbelt. The gneisses and schists, as well as the unconformably overlying Katanga meta-sediments with their stratiform orebodies, have been folded into-overturned to recumbent structures .in which the westerly to northwesterly trend of anticlinal and synclinal axes is closely controlled by the old ridges and valleys, respectively. The overfolding is in turn the result of the incompetent behavior of the gneisses and schists which rode over the rigid buttress formed by the massive Nchanga Granite during orogenesis. Secondary redistribution of copper is believed to have taken place during the folding at one of the orebodies, which is located in the most intensely deformed area. Otherwise the present copper concentrations are still in their original stratigraphic positions. The close spatial relationship between the palaeoridges, the meta-sediments and the associated copper concentrations, suggests a common origin of both sediment and copper from the old ridges. Pre-existing copper lodes in the Basement gneiss and schist are invoked as the source of the copper, which was reconcentrated, either by detrital or chemical means or a combination of these processes, into the sediments at no great distance from the original lodes some of which are still preserved directly under the cupriferous sediments.
Suphide mineral zoning in the Baluba ore body, Zambia1972Vink, B.W.51(3)This paper describes the sulphide mineral zoning through the stratigraphic column in the Baluba copper-cobalt mine in the Zambian Copperbelt. This zoning is explained by changing Eh and pH conditions with time, due to fresh river and rain waters, entering a saline basin.
Preliminary observations on the palynology of the Precambrian Katanga Sequence, Zambia1972Binda, P.L.51(3)This is the first record of microfossils found in palynological preparations of Precambrian metasediments from the Zambian Copperbelt. Argillites and carbonates of the Lower Roan contain clusters of spherical forms, chains of cells, and filaments of algal affinity, which are similar to Precambrian microfossils reported from Australia and Europe. The Mwashia and the Kundelungu groups contain mainly isolated Sphaeromorphida.
Scope of stratigraphic and sedimentologic analysis of the Katanga Sequence, Zambia1972Eden, J.G. van; Binda, P.L.51(3)It is speculated that the Katanga Sequence of the Zambian Copperbelt may have been deposited in a large basin which extended to the southwest into South West Africa. This concept calls for improved regional correlation, particularly since many economic strata-bound deposits in these areas are found in identical stratigraphic sequences of similar age. The Great Conglomerate, partially glacial in origin, can be considered a deposit of the widespread Late Precambrian glaciation and can, therefore, provide a much needed time-stratigraphic marker. The association of the Copperbelt orebodies to particular sedimentary facies may help to delineate trends of mineralization on a local as well as on a more regional scale. The lowermost part of the Katanga Sequence is interpreted as deposited during a regional transgression of the sea which created similar environments along a northwest-southeast belt. Though much of the Copperbelt ore is considered syn-sedimentary in origin, some occurrences are better explained by secondary processes.
Recent contributions to copperbelt geochemistry1972Jolly, J.L.W.51(3)Short abstracts are given of some recently completed investigations bearing on the geochemistry of Copperbelt ore deposits. Three detailed investigations were carried out on veins and altered barren zones in the ore-bearing argillites and footwall quartzites at Chambishi, Luanshya and Muliashi. At all three places, hot fluids have locally altered the host rock, formed veins, leached and remobilized sulphides, and in one case, formed breccia. Comparison of samples from selected parts of the orebody and barren rock at Chambishi has shown interesting mineral and chemical trends that may have important bearing on the origin of the ore. An investigation into the use of mercury in prospecting was also undertaken with some positive results
Ore minerals of the Zambian copperbelt1972Notebaart, C.W.; Vink, B.W.51(3)In this paper, major and minor copper and cobalt ore minerals, presently known to occur in Copperbelt ores, are described briefly.
The geology of the Zambia Broken Hill mine, Kabwe1972Kortman, C.R.51(3)The Zambia Broken Hill ore deposits occur within a belt of dolomitic rocks of Katanga age (Upper Precambrian), which strikes NW and is flanked by shale and phyllite. The main pipe-Iike orebodies, striking WSW, and plunging to the ENE, have a massive sulphide core, consisting of sphalerite, galena and pyrite, surrounded by an oxidised zone containing willemite, smithsonite and cerrussite. An antipathetic relationship exists between lead and iron in the sulphide ore. The wall rock, a pure massive dolomite, was brecciated during oxidation. The breccia matrix consists of jasper-like lithified mud with erratic fragments of oxidised ore. A similar lithified mud is common along the outer margins of the oxidised ore, where it was emplaced through late infilling of cavities.
Summary - Geophysics in the Zambian environment1972Ellis, M.W.51(3)
Introduction into mining an d metallurgy on the Zambian Copperbelt1972Bruggen, J.W. ter51(3)This article gives a general review of technical practices in use at the Zambian copper industry from mining to refining. Some statistics concerning ore reserves and production for 1970 are included.
Open pit planning with the aid of a computer design system1972Pronk van Hoogeveen, L.A.J.51(3)Computer techniques have become increasingly important in planning open pit mines. This article describes a computer system for the design of open pits to mine stratiform orebodies. The system incorporates a modified version of the Open Pit Design Program developed by Rio Tinto Zinc Consultants Ltd. The particular requirements of such a system, for example, the accuracy of representation of geological detail and the ability to follow footwalls, are described in this paper together with the methods that have been adopted to satisfy them. A description of how the computer design program was used to develop the medium and long term mining plans for the Nchanga Open Pit is included.
Underground mining mechanisation at roan consolidated mines since 19651972Collinson, B.M.51(3)A brief description of the ore deposits at RCM's two large underground mines at Luanshya and Mufulira is followed by details of the main mining methods used immediately prior to mechanisation and at the present time. The objectives of mechanisation are listed together with additional benefits that have accrued. Experience with various types of mechanized mining equipment, loaders, trucks, drill rigs and raiseborers is described as are the steps taken to speed up ground support. The article concludes with a description of ventilation, underground maintenance, tyre usage and training.
The water problem in relation to mining at konkola division, Nchanga consolidated copper mines limited1972Rijken, J.H.A.; Clutten, J.M.51(3)Nchanga Consolidated Copper Mines Limited, Konkola Division (formerly Bancroft Mines Limited) is the wettest mine on the Zambian Copperbelt and probably the second wettest in the world. The stratigraphic position of the orebody, between the Hangingwall and Footwall Aquifers, results in large quantities of controllable and uncontrollable water flowing into the workings during mining operations. In 1970 an average of 340 000 cubic metres (75 million gallons) pet day were pumped to surface, equivalent to 64 tonnes of water per tonne of ore hoisted. Sufficient pumping capacity has to be installed to lower the water table in the various aquifers in time to meet production commitments. The sustained capacity for 1972 wiII be in the region of600 000 cubic metres (130 million gallons) per day. The mining method of sub-level open stoping requires dewatering of the Footwall Aquifer during development operations and dewatering of the Hangingwall Aquifers prior to stoping. Water is, therefore, a major consideration in mine planning. A clear understanding of the geological features of the Konkola mining area is essential to develop a successful and efficient dewatering scheme. Dewatering of the various aquifers is achieved by drilling boreholes and by driving mining headings into the aquifers. The problem of recharge is not yet solved and research in this field is in progress, including colour and infrared aerial photographic surveys, chemical and neutron activation analyses of waters, regional water balance studies, and age determinations of waters by natural isotope analysis.
New developments at the leach plant at Nchanga consolidated copper mines limited chingola division1972Bosse, P.J.W.51(3)
Summary - The research and development department of Nchanga consolidated copper mines limited1972Tumilty, J.A.J.; Timmers, J.51(3)
Metallurgical practice at the broken hill division of Nchanga consolidated copper mines limited1972Barlin, B.51(3)A detailed description is given of the metallurgical complex comprising a concentrator, electrolytic zinc plant, sinter plant, Imperial Smelting Furnace and lead refinery used to produce refined lead and two grades of zinc at the Broken Hill mine in Kabwe, Zambia. Flow sheets and 1970 production details are included.
The evolution of petroleum engineering in the last 40 years1972Arps, J.J.51(4)
Stufenweise durchführung von Lagerstättenuntersuchungen unter dem Gesichtspunkt der Wirtschaftlichkeit am beispiel der eisenerzlagerstätte Mano river, Liberia, Westafrika1972Theurkauf, E.51(4)
A new find of a cave hyaena from the Netherlands1972Erdbrink, D.P.51(4)Description of a mandibular fragment of the right side of a Cave Hyaena, found in 1971 near Deventer as the seventh recorded find of this species in the Netherlands, probably from an Eemian deposit.
Das Karbonische alter der Tiefbohrung Wanneperveen I, eine revision1972Amerom, H.W.J. van51(4)A revision of the samples from the borehole Wanneperveen I, The Netherlands, leads to the following conclusions: a) Taeniopteris parva Jongmans nov. sp., published and figured in Jongmans&VanderHeide (1953) can be identified as single pinnules of Neuralethopteris schlehani forma rectinervis (Kidston). b) The non-marine shell described as "Carbonicola" carbonaria in the same above mentioned publication, is now determined as Carbonicola cf. circinata Pastiels 1960. Consequently the age of the fossil baring sediments in the borehole Wanneperveen I must be lowered from the Autunian to the Westfalian A.
Letter to the editor1972Wagner, R.H.51(4)
Samenvattingen van de lezingen symposium "Enkele nieuwe aspecten van Delfstoffen in Nederland"197251(4)
KNGMG Jaarverslag 1971197251(4)
The Tyrrhenian sea - an introduction1972Ritsema, L.51(5)
Deep earthquakes of the Tyrrhenian sea1972Ritsema, A.R.51(5)
Oceanization - geothermal models1972Schuiling, R.D.51(5)
Driving forces of Mediterranean orogeny1972Bemmelen, R.W. van51(5)A critical review of newer data on the Tyrrhenian area (marine geology, land geology, paleomagnetism and seismicity) leads to a formulation of some general aspects of its evolution in Cenozoic time. A solution is suggested for the geodynamic puzzle of Corsica and Sardinia, based on a relativistic structural analysis of the apparent rotations and translations of these islands with respect to a deforming continental frame. During the Cenozoic the central Tyrrhenian area was subjected to pulses of doming and intervening periods of subsidence. The youngest uplift occurred in Mid-Pliocene time and thereafter it collapsed to bathyal depths at a rate of 1 mm/yr. This diastrophic evolution was accompanied by a geochemical transformation of the original continental type of crust (formed during the Hercynian orogeny) into an intermediary type of sialic crust (about 11 to 12 km thick). Meanwhile an orogenic crustal wave migrated radially outward from the Tyrrhenian centre of diastrophism, accompanied by radially outward directed overthrusts, imbrications, and other compressive tectonic features. The driving forces of this orogeny are evidently acting from the concave side of the orogenic arc. The expectations of three geodynamic models of interpretation, advanced for the Tyrrhenian test-case, are compared with the observed aspects of its evolution. These models are (I) plate tectonics, (II) radiogenic heating by the continental crust, and (III) active mantle diapirism. It appears that only the third model provides an explanation which is consistent with the available geonomic evidence.
Über einige molluskenfunde im Wellenkalk von Winterswijk (Niederlande)1972Boekschoten, G.J.51(5)
Nieuw Zeeland en "Plate tectonics"1972Lingen, G.J. van der 51(5)
Enkele aspecten van (geo)mechanische modellenbouw1972Jong, L.N.J. de51(5)
International soil museum197251(5)
Landsliding in the Crati basin, Calabria, italy1972Nossin, J.J.51(6)The Crati basin is flanked on either side by crystalline metamorphic rocks that have been subjected to intensive folding, shearing and crushing, and have hence lost much of their resistance. The basin is filled with Neogene alternations of sand, clay and conglomerates, in a (sub)horizontal position. It is a tectonic depression separated from the metamorphic surroundings by major faults. Post-Calabrían uplift of around 1000 metres, with differential movements superposed, accounts for rapid erosive incision that undercuts the slopes at the foot. Slopes have a further reduced stabitity on account of the loss of coherence in the metamorphics, of frequent faulting and of exposure of water in the slope face, often trapped by Tertiary clay layers and exposed after erosive incision. The main fault-scarp zones separating the basin from the surrounding metamorphics are zones of increased weakness. AII this accounts for an accumulated potential slope instability. Unstable slope zones are identified on air photos, whether they are presently moving or not. Zones in actual movement invariably make part of such larger zones of instability. This movement is mostly triggered off by cutting in the slope for purposes of road construction, frequent in this area under rapid development. Nine characteristic landslides are discussed. The recognition at an early stage in the planning phase, of potentially unstable slope zones from air photos - followed by field verification - allows the foreseeing of difficulties of construction and maintainance of communication lines. This may thus contribute to prevent disasters.
Paleomagnetic reconnaissance study of the Flamanville Granite, with special reference to the anisotropy of its susceptibility1972Voo, R. van der; Klootwijk, C.T.51(6)For a preliminary paleomagnetic investigation of the Flamanville granite (Normandy, France), ten samples were studied. The granite samples had a weak remanent magnetization and a high magnetic susceptibility. The direction of the characteristic remanent magnetization was consistent with other Carboniferous paleomagnetic results from Stable Europe. The high magnetic susceptibility was distinctly anisotropic. The shape and orientation of the susceptibility ellipsoids were determined with the Utrecht astatic magnetometers, according to the method of As (1967). This method has been extended and its practical use is discussed. The orientation of the susceptibility ellipsoids could be interpreted in terms of the mode of emplacement of the granite.
Post-Archeozoic large-scale convection in the earth's mantle1972Vanderzee, T.J.51(6)Static models of the lower mantle do not easily accommodate a cooling of the core on a terrestrial time scale. Moreover, merely shallow flows do not readily explain the present distribution of sial. Therefore, a still active, overall and occasionally reversing mantle convection is proposed that is consistent with the spasmodic character of orogenesis. This convection is compatible with modern estimates of pertinent parameters in a hydrodynamic theory of convection within spherical shells. It bears on the geomagnetic dynamo and helps to explain a correlation that has been suggested between changes in earthquake activity and in the earth's rotation. Apart from tidal dissipation within the mantle, a cooling of a radio-inactive core, on the order of 600°C during the last two and a half to three billion years, seems to be required to complete about a dozen successive mantle overturns.
The Plio-Pleistocene boundary in the North Sea Basin revision of its position in the marine beds1972Voorthuysen, J.H. van; Toering, K.; Zagwijn, W.H.51(6)A revision is given for the definition of the Plio-Pleistocene boundary in marine beds of the North Sea Basin. It has appeared that Elphidium oregonense Cushman & Grant (an arctic species at present living in the Bering Street) characterizes a narrow faunal zone, which falls into the lower part of the first glacial stage of the Pleistocene, the Praetiglian, as defined by means of pollen-analysis. The Elphidium oregonense-zone is presently considered to mark the Plio-Pleistocene boundary. Beds hitherto assumed to belong to the Pleistocene i.e. Merksem beds, "Amstelian", are classified now within the Upper Pliocene.
Changes in vegetation and climate in the Amazon basin and surrounding areas during the Pleistocene1972Hammen, T. van der51(6)
The presence of Nypa palms in Europe: a solved problem1972Haseldonckx, P.51(6)Some new evidences for the autochthony of Nypa palms were found during a palynologìcal study of Eocene sediments in the Spanish Pyrenees. percentages of Spinizonocolpites Muller 1968 of nearly 40 per cent, a possible phylogenetic relationship between Spinizonocolpites baculatus and Spinizonocolpites echinatus and the appearance of fossil pollen and fruits of Nypa, restricted to the Eocene, make it unlikely that Nypa should be transported along the shores of the Tethys Sea.
Holocene Sea Level changes, Cumberland Coast, Northwest England: Eustatic and glacio-isostatic movements1973Andrews, J.T.; King, C.A.M.; Stuiver, M.52(1)Radiocarbon dates on materials from storm-eroded coastal sections plus other dates from peats and wood now below current high tide level are used to construct a preliminary history of relative sea level movement and to derive isostatic and eustatic components of the sea-level changes. Sea-level rose 22 m, relative to the land between 9,200 and 6,000 BP. No information is available for sea level between 6,000 and 3,600 BP but it was probably slightly higher than present. The main Postglacial Beach along this stretch of coast, and the highest evidence of marine action, is ca 5m above average high spring tide level. Shells in this beach date from 2,300±BP which suggests that at least storm waves were reaching these elevations 3,000 years or so after the usually accepted age for the feature. Relative sea-level changes after 3,600 BP were complex and there is at least one soil forming interval recorded. The high coastal sand dunes backing this stretch of coast date from between 1.200 and 1.500 BP. The estimated glacio-isostatic recovery is ca. 18m over the last 13,000 years. Computed eustatic curves indicate fluctuations in world sea-level in the last 5,000 years but these fluctuations could be caused by variations in storminess.
The gravity field of the Papuan Peninsula1973Milsom, J.52(1)Large gravity anomalies on the Papuan Peninsula (the eastern part of the island of New Guinea) are associated with the Papuan Ultramafic Belt, an overthrust ophiolitic complex which may once have formed the frontal zone of an island arc. Very low fields occur over outcrop of the underthrust sialic metamorphics. The extreme east of the peninsula is built up of basaltic lava over which moderately high gravity fields are observed; the structure of this latter area is most simply explained in terms of Recent extensional movements
Displacement patterns of strike-slip faults in Malaysia-Indonesia-Philippines1973Tjia, H.D.52(1)Detailed field studies seven important strike-slip faults in East and West Malaysia, West Sumatra, Java, and Central Sulawesi, used reliable, minor fault-plane markings (bruised step riser, spall, crescentic gouge, lunate fracture, chatter mark, pluck mark, slickenside prod mark) to determine the sense of displacement. The sense of movement on about ten other major transcurrent faults in the region was derived from the literature. A common direction of horizontal compression for each of three tectonic domains that subdivide the region between the Asian and Australian continents is indicated by consistent displacements along the wrench faults. For two of the currently active tectonic domains the directions of regional compression are 10°-190° (for Sumatra and Java) and approximately east-west (for the Philippines and the Indonesian islands east of Strait Makassar). These directions of regional compressions are parallel to compressive stress directions computed from sea-floor spreading rates by Le Pichon (1968) and to earthquake-slip vectors interpreted by Isacks et al. (1968) for the margins of the region under discussion.
De stichting van een mijnmuseum, een urgente zaak1973Raedts, C.E.P.M.52(1)
Evidences of Post-Pleistocene desiccation in South West Ecuador and Northern Peru1973Sarma, A.V.N.52(1)
Verslag kontaktgroep kristalgroei1973Lieth, R.M.A.52(1)
Mineralogical analysis of the "Brown Rain" of February 7th, 19721973Schoorl, R.52(1)
Facies relationships in a tidally influenced environment: A study from the Eocene of the London Basin1973Bosence, D.W.J.52(2)The sedimentology and burrow associations of a lower Tertiary (Lutetian and Cuisian) section in south-east England are described and compared with bedding types described from the Wadden Sea and Rhine estuary. In the lower part two facies are distinguished representing channel and bank deposits. Their relationship, bed forms, fauna and general lack of bioturbation suggest deposition in an inshore tidally influenced region. The sequence is truncated by bioturbated glauconitic sediments of the transgressive Bracklesham Beds.
Sand movement in the in- and offshore tidal area of the S.W. part of the Netherlands1973Terwindt, J.H.J.52(2)This paper deals with the resultant sand movement over the offshore underwater delta along the tidal inlets of the S.W. part of the Dutch coast and with the sediment exchange between the North Sea and the underwater delta. It appears that a complicated circulation of sediments occurs in the whole channel system in the area, mostly directed perpendicular to the general coastline. On the shoals the sand transports by currents are almost negligible. The picture of sand movement by waves suggests a net northeastern sand transport over the shoals. Also the data derived from sediment balances and grain-size differences point to a net northeastern movement of fine sand over the underwater delta. The direction of the sand transport by currents and grain-size data reveal that there is an appreciable sediment exchange between the underwater delta and the North Sea in the Haringvliet area and apparently also along the southwestern part of the underwater delta.
Aspects of the historical and physical geology of the Sunda Shelf essential to the exploration of submarine tin placers1973Aleva, G.J.J.52(2)After a short summary of the geology of the region, mainly based on observations on the tin islands, the original exploration concept is explained: the off-shore area is the drowned continuation of the land area, as studied and explored on the islands, only covered by a relatively thin layer of Recent to Holocene marine mud. The formation of cassiterite placers mainly depends on four genetic factors: primary tin occurences in the basement rocks, chemical weathering of these primary occurences, elutriation or washing out, and the presence of traps. Submarine acoustic profiling has greatly helped in identifying the depositional and erosional sequences, which would not have been possible with the aid of drilling samples only. Contrary to the situation on land, there are at least three sedimentation cycles and one erosion cycle (with a total sediment thickness of up to at least 60 m), covering the Permian basement. In the last chapter the new stratigraphical data are linked up with the principles of tin placer formation, thus leading to a new, considerably less simple, exploration concept.
New results from continuous gasometric determinations of carbonate in cuttings and cores from drill holes1973Schettler, H.52(2)Continuous gasometric determination of carbonate in cuttings has been succesfully used by the Mobil Oil AG in the Weser-Ems area since 1954. It is used to check changes in rock composition (facies development) during drilling and to compare the results with those of adjacent drillings. Cuttings are taken at intervals of 1 to 2 m at the site of drilling; they are washed, dried, and ground. The amount of CO2 is determined with the "Scheibler- asometer" (described in MüIlet,1967) by treating 1/2 gr of the sample with HCl. Absolute carbonate content and the approximate calcite/dolomite ratio can be estimated if the first reading is taken after 30 seconds, the second after 1 minute (sometimes after 5 minutes) and the final reading after the gas development is completed (to 21 minutes). The resulting "carbonate-log" can be compared with those of adjacent drill holes during drilling operation. Such logs are very useful for exploring carbonate reservoirs and for stratigraphic correlation of sections strongly influenced by tectonics and of rocks lacking fossils.
New results from continuous gasometric determinations of carbonate in cuttings and cores from drill holes1973Schettler, H.52(2)Large Enclosure
Stratigraphy, sedimentology and palaeogeography of Eifelian, Givetian and Frasnian strata between the river Porma and the Embalse de la Luna, Cantabrian Mountains, Spain1973Reijers, T.J.A.52(3)The chronostratigraphy of the Middle-Upper Devonian Portilla Limestone Formation is discussed in three stratigraphic sections. Deposition of limestones occurred in a diachronous way. A discussion in four sections, of the sedimentology of the Huergas Formation, the Portilla Limestone Formation and the Nocedo Formation leads to a palaeogeographic picture of two shallow platforms in the west and in the east, resp., on which open marine subtidal to intertidal limestone sediments were deposited. The platforms were separated by a slightly deeper depositional environment into which a delta protruded, eventually filling up the basin. This delta was covered with limestones, similar to those present on the platforms but patchy, irregularly distributed and in smaller thicknesses. The limestone deposition ended with a new, strong pulse of siliciclastic sediments, presumably coming from the NE and spreading out gradually over the whole area. In these sediments, Lower Devonian ferrugenous San Pedro pebbles are present, indicating a deep erosion in the Northern Leonides
A new trace fossil from non-marine upper Palaeozoic red beds in county Wexford and county Kerry, Ireland1973Horne, R.R.; Gardiner, P.R.R.52(3)Previously unrecorded radially symmetrical, apparently cylindrical or downward tapering structures in red, non-marine siltstones and sandstones of Devonian to early Carboniferous age are described from south-west County Wexford and the Dingle Peninsula, County Kerry, Ireland. These structures are interpreted as biogenic trace fossils rather than inorganic features. They are most probably dwelling burrows, possibly of a fresh-water coelenterate. The most comparable known forms are LaevicycIus Quenstedt, 1879, Kulindrichnus Hallam, 1960 and Bergaueria Prantl,1946.
Sedimentary structures in the Southern and Central portions of the waterberg area, Northwestern transvaal1973Vries, W.C.P. de52(3)Sedimentary structures in the Waterberg System comprise transverse current ripple marks, linguoid ripple marks, cross-bedding, ripple marks on foresets of cross bedding, normal type of convolute structures and so-called convolute lump structures which occur on the upper bedding plane of a convoluted bed.
The type Campanian and the Campanian-Maastrichtian Boundary in Europe1973Gorsel, J.T. van52(3)In his description of the type Campanian Coquand mentioned two localities in which his Campanian unit occurs. Later investigations showed that the two sections are not exact time equivalents. As a result controversies arose whether the one or the other unit should be the type Campanian. The simplest solution is to consider both units as Campanian stratotypes, one representative for the lower part and the other for the upper part, the more so as this agrees quite well with usage outside France. Between the top of the upper Campanian type section and the base of the Maastrichtian type section a time gap exists. In this time gap the boundary between the geochronologic units Campanian and Maastrichtian has to be drawn. It is suggested to adopt the boundary of Seitz (1952) because this boundary is commonly used and because its use is in accordance with the priority principle
The Thal interfluve, Pakistan. Geomorphology and depositional history1973Higgins, G.M.; Ahmad, M.; Brinkman, R.52(3)Landforms and depositional history of the semi-arid and arid Thal desert and the adjoining Indus floodplain in Pakistan are described and discussed. Climate and sand relief are controlled by three wind regimes: southern monsoon from the Arabian Sea and eastern monsoon from the Bay of Bengal in summer, and northern winds in winter. Present vegetation ranges from wooded steppe to (arid) desert steppe. The sands deposited by the Pleistocene Indus river were reworked into longitudinal and transverse ridges, alveolar (honeycomb-pattern) sands and locally barchan dunes, depending upon wind directions and forces. Abandoned Pleistocene Indus channels containing narrow clayey strips occur in this area, the eastern ones mostly obscured by wind resorting. The Holocene Indus floodplain shows four depositional stages: the sandy base of a braided river system; two stages of a thin finetextured cover; and recent moderately coarse sediments
Jamaica's Pleistocene reef terraces1973Cant, R.V.52(3)
Highlights of Zambia's mineral industry in 1972197352(3)
Verslag van het "international colloquium on Messinian events in the Mediterranean"197352(3)
Politieke en ethische aspecten van de grondstoffenvoorziening1973Uytenbogaardt, W.52(4)
Gravitational gliding in the Northern Sierra de Los Filabres (SE Spain)1973Langenberg, C.W.52(4)Evidence is given for rotatory movements of klippes in the northern Sierra de los Filabres. Use has been made of difference in the orientation of linear structural elements in the klippes compared with that of equivalent structures in the underlying 'basal succession'. The rotations indicate gravitational gliding, probably resulting from updoming of the mountain-range in a late stage of the orogenic history.
Holocene transgressions and regressions on the Essex coast outer Thames estuary1973Greensmith, J.T.; Tucker, E.V.52(4)Faunal and lithological changes within the 34 m of Holocene sediments of the chenier plain suggest six episodes (l-VI) of marine transgression interspersed with five episodes of regression. Evidence presented for recognising transgressions includes chenier formation, marsh retreat and vertical changes in fauna, involving brackish water and intertidal molluscs. Regressions are interpreted chiefly from geosols and peat seams. Radiocarbon dates indicate that the transgressive episodes lI, lll and V first affected the region at about 7500, 4000 and 1400 B.P. respectively. The most recent one (VI) probably commenced about 300 B.P. The dates of episodes I and IV can only be conjectured. Comparison with similar events globally as well as in the Low Countries suggests that eustatic changes in sea level have played a significant ¡ole in the Holocene history of the Outer Thames estuary.
The sedimentary environments of Tropical African estuaries: Freetown Peninsula, Sierra Leone1973Tucker, M.E.52(4)Four main environments are described from tropical estuaries of the Freetown Peninsula, Sierra Leone: A) sand bats, B) channels, C) intertidal flats and D) mangrove swamps. The sand bars are predominantly well-sorted medium sands, with dunes as the main bed form. The channel sediments vary in grain size and bed form up the estuaries, but generally contain lag deposits (mostly of shell debris and laterite pebbles) coarser than the adjacent intertidal sediments. The intertidal flats are mostly muddy sands, commonly with scour pits and current lineation. The sedimentary structures are obliterated by infaunal bivalves and burrowing crustaceans. The mangroves, developed peripherally around the estuaries, are important in trapping and binding the finer grades of sediment. Sierra Leone has an extreme two-season climate, considerably affecting the estuarine sediments. During the dry season, a period of accretion, much sediment (mainly bed load) is taken into the estuaries from offshore. Crustaceans and bivalves increase in numbers and occupy a larger area of the intertidal flats. During the wet season, mud and plant debris are brought down by the rivers and some bed load is moved down or out of the estuaries. With rising sea level, the estuarine deposits are prograding landward, over fluviatile sediments and soils (laterite in this case), producing a coarsening upward sequence from rootlet beds through bioturbated muddy sands to well-sorted cross-bedded medium sands.
Influence of crystallographic habit and aggregate structure of authigenic clay minerals on sandstone permeability1973Stalder, P.J.52(4)Our studies have shown that shifts in the trend of the permeability/porosity relationship for sandstones may be explained in terms of the crystallographic habit and aggregate structure of authigenic clay minerals. It is also suggested that the specific surface (surface/volume ratio) of the clay minerals (either authigenic or detrital in sandstones) could account quantitatively for the different permeability/porosity relationships and might represent a parameter that could be introduced into conventional permeability/porosity plots. It is assumed that a high specific surface of the interstitial clay minerals will induce tortuosity and therefore turbulence at higher flow rates and will also cause pore-space reduction by favouring water adsorption on the large available clay-mineral surface. The thread-like habit often observed for authigenic illite will also cause a division of pore space into a large number of tiny holes, through which fluid flow is much more difficult.
On the presumed dimorphism within halysites colonies1973Boer, P.L.52(4)Dimorphism does not exist in Halysitidae. The mesocorallites as defined by Buehler (1955) and the microcorallites and mesocorallites as defined by Hamada (1958) are considered filling structures; the author prefers the more descriptive term tubules for these skeletal features. The taxonomic importance of the distribution of these tubules in the corallum is questioned.
Use of Berek compensator made still easier1973Jagadiswara Rao, R.52(4)
"Symposium kristalgroei" Noordwijkerhout Mei 19731973Carpay, F.M.A.52(4)
KNGMG Jaarverslag 1972197352(4)
In memoriam - Prof. Dr. Ir. H.A. Brouwer1973Egeler, C.G.52(5)
Significant relations between textural and structural features of the rocks in the Churchbay-, Templebreedy members of the uppermost Old Red Sandstone complex, South of Cork, Ireland1973Leflef, D.52(5)The alluvial rocks in the lower part of the uppermost Old Red Sandstone Complex show a significant relationship between their structural and textural features. In the area presently dealt with the encountered rocks are of sandstone, "intermediate", and mudstone facies which together allow a further subdivision into 7 rocktypes according to the above relationship. Each rocktype is characterized by its own association of structures and its own grainsize range. Two types of structures were found to exist: namely those which vary upon grainsize variations and those which do not. The latter category embraces horizontal lamination and low-angle cross-lamination. The category, the structures of which vary upon grainsize variations, comprises mostly high-angle cross-lamination. The distinguished rocktypes are regularly organized in vertical sequences, as well as in down-current developments, reflecting the changing flow conditions during time of deposition.
Lássociation spilites-quartz Keratophyres du Sud-Ouest de la Peninsule Iberique1973Soler, E.52(5)Submarine volcanics were emplaced along tension faults developed along a pre-orogenic flexure zone in the southwestern Iberian peninsula. The age of these extrusions is placed between the Famennian and upper Visean. The lavas belong to the spilite-quartz kelatophyre association, with the latter strongly prevailing. Investigation of these rocks indicates two different series (a very acid one and a basic one) but without gradations. This is explained through mobilization of sialic crustal material by basic injections. The primary basic magma could have been basaltic; it may have been contaminated by sialic material and, to a greater extent, by the thick sedimentary pile which still contained connate waters and which the basaltic magma had to penetrate before reaching the sea bottom. Hybridization did not occur but rather contamination
On the tectonics of an area near Laujar, Sierra de Gador, Spain1973Rutter, E.H.; Gibbons, M.J.52(5)A small area exhibiting contact relationships between schists of the Sierra Nevada, rocks of the Mischungzone and rocks of the Alpujarride complex, in the Betic zone of Southern Spain, has been studied. It is shown from field observations that the rocks of the Alpujarride complex suffered at least one early deformation coeval with low grade regional metamorphism, and involving tectonic transport from south to north. This was followed by gravity sliding from north to south. Fault surfaces associated with these later movements provide the most obvious evidence of tectonic disturbance in the area. The results of a petrofabric study of twin lamellae in a Mischungzone marble are consistent with the hypothesis of a late phase of gravity induced sliding.
Lijst van lopende tijdschriften in het bezit van het genootschap, door ruilverkeer verkregen aanwezig in de bibliotheek van de afdeling mijnbouwkunde, T.H. Delft1973Dozy, J.J.52(5)
Pre-Bauxite red sediments and sedimentary relicts in Surinam Bauxites1973Valeton, I.; Jürgens, U.; Khoo, F.52(6)In Surinam, in the northern Guiana foreland, two sections of pre-bauxite sediments and two sections of bauxites were studied for origin and composition of the primary material and the pre-bauxite diagenesis, These sections are composed of "red sediments" of the clastic hematite-kaolinite-quartz association from pre-bauxite time; These sediments are erosion products of deeply weathered laterite and were formed in shallow water around basement plateaus. The base of the sequence indicate very turbulent sedimentation; in between we find periodic occurrence of plant roots; on top (today bauxite) there is evidence for new transgression and quiet sedimentations (burrows). The diagenesis of the underlying sediment (here pre-bauxite) is characterized by kaolinization of the lower and gibbsitization of the upper sequence. The type of these red sediments, as characterized by mainly detritic hematite and kaolinite and lack of feldspars, is very uncommon.
A change in rocktypes associated with the approaching shoreline of the Old Red continent, South of Cork, Ireland1973Leflef, D.52(6)The alluvial rocks in the upper part of the Upper Old Red Sandstone (Fennelsbay member) show a less stringent relationship between the structural and textural features than those of the lower part (Churchbay-Templebreedy members). Though this phenomenon is not readily explainable by a paleogeoglaphical development, it is concomitant with well-known changes betraying an approach of the shoreline - such as improved sorting and maturity of sandstones, gradual disappearance of red coloured rocks, and first occurrence of heterotithic rocks – characteristics which are even more strongly in evidence in the overlying Ballinluska member which is of proven (fossils) marine character.
Two fragmentary mandibles of archidiskodont elephants from the Netherlands1973Erdbrink, D.P.; Augustinus, P.G.E.F.52(6)Description of two incomplete mandibulae or Mammuthus (A.) meridionalis dredged up in the Netherlands at Appeltern on the Meuse and at Lathum on the lJssel. Each belonged to a very old and probably male individual. A Cromerian age and a provenance from the Lower Rhine terraces in Germany is considered possible in each case, but heavy minerals analysis does not lead to conclusive evidence.
A simple method for accurate alignment of X-ray diffraction goniometers1973Jansen, J.H.F.; Gaast, S. van der52(6)Accurate alignment of an X-ray diffraction goniometer can easily be obtained if direct scanning of the X-ray beam is used to adjust both the dial of the goniometer and the specimenholder.
Quelques aspects de la concentration des minerais et de son evolution1973Formanek, V.53(1)La concentration des minerais est un sujet très vaste; c'est pourquoi je me limiterai à parler suelement de certains procédés de concentration en m'appesantissant un peu plus sur l'évolution du procédé de flottation
An aragonite-cemented volcanic beach rock near Bilbao, Spain1973Knox, G.J.53(1)An unusual beach rock occurs near Bilbao. The beach is aragonite-cemented and contains melilites/volcanic glass fragments for which there is no apparent source. Man-made bricks and fresh bone fragments suggest that the beach is very young
Hinge movements influencing deposition during the Upper Devonian in the Esla area of the Cantabrian Mountains, Spain1973Reijers, T.J.A.53(1)In the Upper Devonian succession the presence of allochthonous lithological elements and replaced fossils, a regular vertical alternation of layers of coral rubble and biostromes, and abundant indications of erosion and subareal exposure can be explained by application of a regional epeirogenetic model. Epeirogenetic movements governed sedimentation and led to a regressive and a transgressive depositional phase. The Portilla Limestone Formation and the Nocedo Formation have been mainly deposited during the regressive phase; the deposits of the Ermita Formation reflect the transgressive phase.
Analysis of geological information on computer files1973Bär, C.B.53(1)
Storage and retrieval of geological data1973Mentink, H.G.53(1)
A future for induced geothermal energy?1973Schuiling, R.D.53(1)The possibility of using geothermal energy in non-volcanic, normal areas is discussed. An attempt is made to apply this concept to the Netherlands, where the geothermal gradient is in general above the world's average. If geothermal heat production from non-volcanic areas will ever be feasible, technologically or economically, is still very uncertain.
In memoriam - Prof. Dr. D.J. Doeglas1974Nota, D.J.G.; Plas, L. van der53(2)
Explanation to tectonic maps of the Netherlands1974NAM; Heybroek, P.53(2)Three structural contour maps and three geological maps at different levels covering the Netherlands are presented and discussed. The levels depicted are the top Carboniferous, the base Cretaceous-Upper Jurassic and the base Tertiary. The maps are discussed in relation to the tectonic history of the Netherlands. The deformation is classed as intracratonic, epeirogenetic. Three successive patterns of movement are recognized: the Permo-Triassic, the Jurassic-Lower Cretaceous, and the Cenozoic. They are basically different from each other but relatively constant in themselves. The Jurassic-Lower Cretaceous pattern and its inversion in the Upper Cretaceous receives special attention.
Explanation to tectonic maps of the Netherlands1974NAM; Heybroek, P.53(2)Large Enclosure 1
Explanation to tectonic maps of the Netherlands1974NAM; Heybroek, P.53(2)Large Enclosure 2
A practical method for optical spectroscopy of crystals1974Lagerwey, A.A.F.53(2)In this article a recently developed method for optical spectroscopic analysis of crystallized substances is introduced. The practical method proposed is non-destructive, and the apparatus required is relatively simple and inexpensive. Principles of optical spectroscopy for the analysis of trace elements in complex crystals are reviewed; essential aspects of this method and other routine methods are compared. Next, the nature, scope, and limitations of the new practical method are discussed, and the information, which can be obtained, is summed up. In essence, the procedure consists of the sequential registration of absorption- and luminescence spectra of the substance to be examined, and the subsequent analysis of both spectra. Details of the apparatus required, and of the analysis procedure are treated in the following section; different methods for obtaining good quality absorption- and luminescence spectrograms are reviewed here. An important feature of the method is the excitation of luminescence with blue radiation; the advantages of its use are critically discussed. Facultative refinements of apparatus and method, making possible polarisation spectrography and topographical spectrography of macrocrystals, are indicated. Requirements for preparations for the purpose of calibration are mentioned. The practical value of the new method is demonstrated by results, obtained in the process of determination of some definite typochemical varieties of the crystallized minerals scheelite, apatite, zircon, spinel and topaz; these varieties are described. Finally, possible applications in the fields of mineralogy, gemmology and geochemistry, chemistry and physics, and even in industry, are reviewed. It is expected, that the proposed method will develop into a practical tool for routine researches in these branches of science.
Reactivering van de Nederlandse steenkolenmijnbouw bij de huidige oliecrisis?1974Weehuizen, J.M.53(2)
Holocene sea-level changes: a discussion1974Shepard, F.P.53(2)The sea-level curve by Greensmith and Tucker, based on coastal work in southeastern England, is said to conform with other worldwide evidence of Holocene sea-level changes, notably that of Fairbridge and Mörner. However, the curve shows little relation to that of any previous investigators, and contrasts greatly with that of Fairbridge because it shows a lack of appreciable sea level higher than that of the present day.
Holocene sea-level changes: a reply1974Greensmith, J.T.; Tucker, E.V.53(2)
Outline of the Precambrian geology of Southern West Greenland1974Allaart, J.H.; Escher, A.; Kalsbeek, F.53(3)The Archaean gneiss block of West Greenland is made up of gneisses, amphibolites and anorthositic rocks and contains the oldest crustal rocks yet known on earth. The Archaean block is bordered to the south by the Ketilidian mobile belt, largely consisting of younger granitic intrusions and to the north by the Naggsugtoqidian mobile belt which mainly consists of reworked Archaean rocks.
Some aspects of the definition of iron ore1974Kramer, G.M.53(3)Several aspects of the definition of iron ore, as presented in the "Survey of World Iron Ore Resources" of the United Nations, are reviewed. Due to the variety of iron ore formations no general cut-off grade can be indicated. Some outside factors can be of decisive importance for an ironbearing formation reaching the "ore" status.
Scanning electron microscopical observations on weakly cemented Miocene sands1974Riezebos, P.A.53(3)The cementation that has led to the local formation of slightly indurated layers in the white Miocene sand deposits, is due to authigenic quartz growth. Scanning electron microscopical information reveals that the secondary quartz is not only found at the grain contacts. A rather unexpected finding is its presence all around very small as well as large grains. The former ones show the most advanced idiomorphic habit and seem to play an actual part in the cementation. Presolved surfaces could not be found, so that the used silica does not appear to be produced by pressure solution. It is concluded that the grain surfaces must have been clean and highly disturbed before cementation started. This is, because only such surfaces seem to provide numerous suitable sites for nucleation, which may result in a comparatively rapid and full-scale overgrowing. However, since silica under certain conditions also dissolves very readily from disturbed surfaces, it is still possible that a part of the crystallized silica has come from the deposit itself. This particular type of early stage of cementation suggests strongly that the nature of the detrital quartz grain surfaces may be a very important factor in the kind of silica cement being formed. It is suggested that the origin of these weakly indurated layers must have been associated with seasonally rising and falling silica-bearing groundwater
A discussion of new results from continuous gasometric determinations of carbonate in cuttings and cores from drill holes, by Schettler, Vol. 52(2) p. 93-991974Abbott, B.M.53(3)
"Swlling clay minerals in sediment-petrographical analysis"1974Quakernaat, J.53(3)
in de greep van tijd1974Priem, H.N.A.53(4)
Van Waterschoot van der Gracht penning197453(4)
Spoorelementen in het grondwater197453(4)
Trace elements in the waters of the dune water catchment area with artificial recharge of Amsterdam1974Engelen, G.B.53(4)
Heavy metals as trace constituents in natural groundwaters and polluted1974Matthess, G.53(4)The natural and man-made concentrations of heavy metals are discussed concerning their abundance, geochemical mobility and their physiological effects on man. The many gaps of geochemical information concerning abundance and behaviour of heavy elements in the ground should be filled especially for those elements which are important to human health.
Inventory of trace elements in groundwaters of the Netherlands1974Brinkmann, F.J.53(4)An investigation of the Dutch groundwaters as for trace elements has been started. A sampling method has been developed. The results of the first measurements are given. They concern groundwaters from the East of the country as well as from the dune region. The investigation is handicapped by the fact that observation pits may be contaminated by rests of drilling fluid. Contrary to the first intention, production pits are also sampled now. The measurements will be extended to a complete sampling network.
The contamination of Dutch soils with mercury and a few other heavy metals1974Frissel, M.J.; Poelstra, P.; Klucht, N.53(4)As a result of his history the average dutchman knows the various soil types in his country quite well, the chemical structure is usually unknown. The paper describes the typical aspects of the soil constituents as there arc clay minerals, sands and organic materials, Specially the properties, which control the adsorption of traces of heavy metals and pesticides got attention. An important part of the paper is devoted to the behaviour of mercury in dutch and other western european soils. Because part of the drinking water companies in the western part of Holland produce their drinking water from the River Rhine by filtration through dunes, the migration of mercury in soils got serious attention. Most mercury compounds (Hg, HgCl2, HgCICH3) do not migrate in soil, the volatile Hg (CH3)2 migtates fast. The contamination of soils is partly caused by agricultural measures' partly by flooding with water from the Rhine. An analysis of the available data indicated, however, that the main mercury source stems from the wash out of the atmosphere. The contamination of soils in areas with a high population density and much industry is considerably higher than in other areas. A similation model was developed to describe the mercury fall out drain rate.
Reflections on groundwaterpollution by tipping of solid wastes1974Mesu, E.J.53(4)In the following paper is stated that groundwater-pollution caused by waste-tips is of very little significance. That is when is token that the waste is never dumped in open surface-water nor below the groundwater-table and that the subsoil does not contain gravel-layers nor bear ('karst"-phenomena or open fissures. Besides it appears that the leachate from a tip contains most pollution during the first years after tipping and that after two or these years this pollution diminishes gradually. The microbial breakdown of the waste and the herewith formed products play a big role in the purification-processes in the soil. Organic material is needed for the development of this microflora. This induces to the opinion to combine the tipping of certain types anorganic (chemical) waste with urban waste (high organic content) rather than to tip it separately.
Government revenues per barrel in the OPEC-countries 1957-19731974Tamboezer, R.G.53(4)This paper covers the evolution of government-revenues per barrel of exported crude oil in the OPEC-countries from 1957, when the major oil-companies lowered their posted prices and thus the government revenues, through September 1973, when the ¡elation between the oil-companies and the governments had so drastically changed that the recent enormous posted-price-increases could virtually be decreed by the OPEC-governments without any recognizable influence from the company-side. Also an indication will be given of the evolution of the realized prices of crude oil over that period. In appendices, tables and figures government revenues per barrel of exported crude, volumes of exported crude and total government revenues will be given for three representative OPEC-countries (Saudi Arabia, Libya and Venezuela) and for the total Middle-East, both in current dollars and in constant dollars (1957 $).
Kyanite in the Hercynian metamorphic rocks of the Oporto-Viseu belt, North Portugal1974Atherton, M.P.; Atkin, B.P.; Naggar, M.H.53(4)Kyanite and garnet have been found in some metamorphosed rocks of the so-called low-pressure Oporto-Viseu belt of the Older Hercynian granites, Portugal. Reassessment of the nature of the metamorphism is therefore necessary, as well as its relation to the higher pressure, Barovian metamorphic belt to the west (Oliveira de Azemeis).
A note on lower pressure and higher pressure metamorphic belts in North Portugal1974Oen, I.S.53(4)In north portugal a lower pressure metamorphism occuring in belts associated with Older Hercynian Granites includes low and intermediate pressure facies types. A higher pressure metamorphism occurring in belts outside the main granite area includes intermediate to high pressure facies types.
De natuurlijke erosie als basisniveau voor het transport van elementen1974Schuiling, R.D.53(4)
Koper en zink in de Waddenzee1974Duinker, J.C.; Eck, G.T.M. van; Nolting, R.F.53(4)
Zware metalen in riviersedimenten1974Driel, W. van; Groot, A.J. de53(4)
Natuurlijke en versnelde mobiliteit van fosfaat1974Golterman, H.L.53(4)
De mobiliteit van fluor op mondiale schaal1974Aronds, C.A.53(4)
Verblijfstijden van Zn en Cd1974Weyden, C.H. van der53(4)
KNGMG Jaarverslag 1973197453(4)
In memoriam - Prof. dr. I.M. van der Vlerk1974Hammen, T. van der53(5)
The hercynian diastrophism in the Betic of Málaga, SE Spain: a discussion1974Roep, T.B.53(5)Arguments for and against a hercynian diastrophism in the Betic of Málaga (especially of the Vélez Rubio region) are briefly discussed. It is concluded that the transition in facies, from Paleozoic turbidites to a Permo-Triassic alluvial fan, and the contrast in detritus of the Paleozoic and Permo-Triassic sediments favour the hypothesis of a hercynian diastrophism.
Waste disposal and underground waters1974Visser, W.A.53(5)Underground waste management, environmental ìmplications and artificial recharge were the subjects discussed in two symposia, respectively in Houston, Texas, in 1971 and in New Orleans, Louisiana, in 1973. In the present paper the author summarizes aspects of the injection of liquid wastes into reservoir rocks by deep wells in the U.S.A. These aspects concern legislation and policy, statistics and actual conditions in some regionally important disposal Zones. Attention is given to the protection of useful subsurface waters Ground waters, i.e, those waters that take part in the present hydrologic cycle, and formation waters, i.e. those that are isolated from the present cycle, are distinguished. Disposal in the former constitutes a potential hazard to the environment, in the latter under certain precautions disposal may be considered safe. In The Netherlands conditions are such, that aquifers that are properly isolated from the present hydrologic cycle occur at depths greater than between approximately 500 and 1000 m. Below these depths disposal prospects are present in sandstone/ claystone alternations of upper Palaeozic to Tertiary age and possibly in upper Cretaceous limestones. In the northern and eastern parts of the country solid or liquid (including radioactive) wastes could be disposed of in artificial caverns in rock-salt deposits.
Enige technieken en markteconomische aspecten met betrekking tot de fabrieksmatige verwerking van steenkool tot gasvormige of vloeibare energiedragers1974Geertman, G.H.M.; Steeman, J.W.M.; Wetzels, F.J.53(5)First a review is given of the existing techniques and current development in the application of coal as an energy carrier, when the disadvantages attached to the use of coal is avoided. This technical part deals mainly with the process technology of manufacturing SNG and/or crude from coal and the generation of electricity from coal respectively. Secondly, the (future) commercial proposition of these techniques is valuated by determining the unit costs of the product (depending on conversion costs and the upset-price for the coal) and comparing this with the price development of alternative energy. For USA conditions it is expected that, in spite of the relatively high costs of conversion, a competitive SNG market price can be realised, being the result of a low cost price for coal ex mine. A competitive SNG price on the basis of European coal does not seem attainable. However, in Europe a competitive production of SNG may be achieved, provided that the price of imported coal does not appreciably exceed the technical cost price. If on the other hand the price of imported coal is based on a calorific equivalence with heavy fuel oil, SNG prices do not seem competitive with natural gas prices, unless this SNG will be used for 'heavy' premium markets (non-industrial public use). Conversion of coal into liquid fractions is much more expensive than conversion into SNG and therefore probably will nog be initiated very soon under the existing European conditions. For, SNG may serve as a substitute for heavy oil fractions and middle destillates (e.g. in industrial and domestic applications); the latter in their turn may be converted into light fractions via "cracking" at relatively low conversion costs.
De problematiek van de ondergrondse vergassing van steenkolen1974Stuffken, J.; Wetzels, F.J.53(5)Underground gasification on an industrial basis seems not applicable to European coalreserves. This conclusion is based on considerations of a technical, environmental and - especially – commercial nature. The main technical problems for European conditions are described: combustion process control, roof control, joining boreholes, control and elimination of leakage (incl. short circuit and leakage of combustion gas to the banking level), water influx into the gasification area, geological features, etc. Past experiments are very disappointing and indicate that no solution whatsoever was found for the numerous and complex technical problems. From an environmental point of view, a number of drawbacks are presented. In commercial respect underground gasification of European coal is not competitive at all because the calorific cost price of the gas produced is quite at variance with current and future prices for energy. This price discrepancy is of such a magnitude that there is serious doubt about the commercial viability of this energy source even on the very long range. Finally, no serious argument can be put forward from a strategic point of view, because of the minute share in European energy supply even in case of a large scale underground gasification program.
On the evolution of structure and metamorphism during the alpine orogeny in the eastern and central Betic Zone (Betic Cordilleras, Spain)1974Egeler, C.G.53(5)The relationships between Alpine overthrusting, folding and regional metamorphism in the eastern and central Betic Zone are discussed, in the light of recent studies. It is substantiated that two major episodes of metamorphism had occurred, related to distinct stages of the orogenic evolution. In this there is a marked analogy with the evolutionary trend of the internal zone of the Alps. The conspicuous difference between the two belts lies in the time relationship between the final emplacement of the nappes and the 'main' episode of crystallization. In the Betic Zone it is the early episode that has determined the overall 'picture' of the metamorphism.
The Westphalian of the Netherlands with special reference to microspore assemblages1974Wijhe, D.H. van; Bless, M.J.M.; Dijkstra, S.53(6)The Westphalian in The Netherlands can be subdivided into six biostratigraphical miospore zones. Each zone is distinguished by an assemblage of several characteristic species, which individually are not restricted to a particular zone with the exception of Radiizonates aligerens. Top and base of each zone are characterized by the first or last (regular) occurrence of a particular diagnostic species. In the Upper Westphalian A and Lower Westphalian C a distinct correlation exists between the microfloral and major lithological changes, which suggests that the Westphalian floras have been at least partly influenced by paleoecological factors.
Aspects of Permian, Triassic and Early Jurassic palynology of Western Europe - A research project1974Clement-Westerhof, J.A.; Eem, J.G.L.A. van der; Erve, A.W. van; Klasen, J.J.; Schuurman, W.M.L.; Visscher, H.53(6)A palynological research project in the Permain, Triassic and Lower Jurassic of western Europe is briefly outlined. The project is aimed at the development and promotion of palynology as a primary tool in regional stratigraphical classification and correlation. A number of examples of specific topics currently under investigation are briefly discussed, viz. (1) a Cordaitina-assemblage from the Permian Collio Formation of northern Italy, (2) Late Permian megaspores from the Vicentinian Alps, Italy, (3) palynological assemblages from the Muschelkalk and Lettenkohle of Luxemburg, (4) a palynological reconnaissance study in the Keuper of Spain, (5) palynological assemblages from the uppermost Rhaetian of the Northern Limestone Alps in Germany, and (6) palynological assemblages from the Lower Jurassic of the Vicentinian Alps, Italy. It is emphasized that regional palynological studies should be integrated in international multidisciplinary stratigraphical projects.
Palynology of Rhaetian, Liassic and Dogger strata in the Eastern Netherlands1974Herngreen, G.F.W.; Boer, K.F. de53(6)Rhaetian, Liassic and Dogger sediments have been examined palynologically from boreholes, mainly located in the Achterhoek area, eastern Netherlands. The results are presented in seven pollen diagrams and a distribution chart; seven pollen zones have been recognized and illustrated (6 photoplates). A range chart of selected palynomorph types has been designated, covering the uppermost Triassic-Dogger strata. Some concluding remarks concerning Liassic tectonic movements are made.
The palaeogeographic evolution of the Netherlands during the Quaternary1974Zagwijn, W.H.53(6)An outline of the palaeogeographic evolution of the quaternary sedimentary basin of The Netherlands is given, based on a discussion of 12 maps, figured in the enclosure. In the second part of the paper a documentation of the sources used is given.
The palaeogeographic evolution of the Netherlands during the Quaternary1974Zagwijn, W.H.53(6)Large Enclosure
The last interglacial-glacial cycle: state of affairs of correlation between data obtained from the land and from the ocean1974Wijmstra, T.A.; Hammen, T. van der53(6)An attempt is made to evaluate the state of affairs of correlation of deep sea curves, long palynological sequences in terrestrial deposits and the stratigraphical sequence in NW Europe. There seems to be little doubt about the correlation within the reach of normal 14C dating (approximately covering the last 50,000 years), corresponding with oxygen isotope stages 1, 2 and, at least partly, with 3. If the indirect dating of the temperature minimum of stage 4 as approx. 70,000 B.P. is correct, a correlation with the Lower Pleniglacial becomes less probable and a correlation with one of the cold phases in the Early Weichselian much more likely. In that case, at least as the Macedonian region is concerned, a correlation of stage 4 with the dry phase between the Drama and Elevtheroupolis intervals seems to be the most probable.
Eine Interstadiale Torfschicht bei Nijmegen (Niederlande) und deren Bedeutung für die Erklärung der dortigen landschaftsmorphology1974Teunissen, D.; Teunissen van Oorschot, H.53(6)An interstadial peat layer near Nijmegen (The Netherlands) and the meaning of this layer for the explanation of the surrounding landscape morphology. The Geological Map of The Netherlands (1935,1947) defines the sandy plain west of the glacial push moraine of Nijmegen as a fluvioglacial drift plain. Pons (1957) has noticed, that this plain is divided into two steps. These steps are separated by a low landscarp. We suggest that the Würm glacial dry valleys of the upper step terminate at the landscarp and that the lower step does not consist of Riss glacial sandr material as was thought previously, but that it is composed of the laterally fused, very flat alluvial cones of the dry valleys of the upper step. We base this opinion mainly on the presence of a moershoofd-interstadial (ca.45.000 years old) peat layer in the sediments of the lower step.
Implications of a pollen diagram from the Adriatic Sea1974Bottema, S.53(6)A pollen diagram from the shelf of the Adriatic is presented and compared with diagrams from the adjoining mainland and with pollen spectra from Mediterranean deep sea samples. This comparison may give information on local pollen production on the mainland as well as on the influence of secondary pollen in deep sea sediments. Next to palynological dating, volcanic ash layers may provide more precise dates. It seems that for palynological investigations cores from shallow water are preferable to those from deeper water.
Palynological and paleoecological investigations in the Vosges (France): a research project1974Janssen, C.R.; Kalis, A.J.; Tamboer van den Heuvel, G.; Valk, E.J. de53(6)In order to reconstruct the Late- and Post-glacial vegetation development of a west-eastern belt in the Vosges (France) palynological and paleo-ecological investigations were made. One map and five simplified diagrams are shown and will be discussed. The map shows the area in study. On basis of differences in geology and relief the area has been divided into five regions. In this paper the central region receives most interest. A diagram of surface samples taken on a mountain summit, shows the local and/or regional deposition of several pollentypes. These results are used for the interpretation of pollendiagrams and it is possible to base a zonation on regional pollentypes as far as late Post-glacial pollendiagrams are concerned. In two diagrams the trends in the curves of some regional pollentypes have been correlated to historical events and it also seems possible to reconstruct fluctuations of the upper forest limit. Figure 6 shows differences in pollen percentages in profiles of two bogs, which may be due to the existence of a vegetation zonation in the older Post-glacial.
Palynological and paleoecological investigations in the Vosges (France): a research project1974Janssen, C.R.; Kalis, A.J.; Tamboer van den Heuvel, G.; Valk, E.J. de53(6)Large Enclosure
Niederwil, a palaeobotanical study of a swiss neolithic lake shore settlement1974Zeist, W. van; Casparie, W.A.53(6)In 1962 and 1963, excavations were carried out in the Neolithic lake shore settlement of Niederwil, in northeastern Switzerland. The site, which is dated from ca. 3700 to ca.3625 B.C. (bristlecone pine calibrated 14C dates), was founded on gyttja and overgrown by peat. In the settlement remains the conditions were favourable for the preservation of organic material. Information on the vegetation in the vicinity of Neolithic Niederwil is based upon the results of the examination of plant macrofossils, mainly wood, seeds, and fruits, recovered from the site, and upon the palynological study of sediment cores from outside the settlement. At the time the natural vegetation of the uplands consisted of Carpinion betuli forests, in which, in addition to oak and beech, various other trees and a larger number of shrubs were found (table 1). In the river valleys Alno-Padion forests with poplar, ash and elm would have been present. In consequence of cutting and grazing, open vegetations came into existence (table 2), while Prunetalia shrub vegetations expanded considerably along forest edges. The main crop plants of the Niederwil farmers were bread wheat (Triticum aestivum), naked barley (Hordeum vulgare var. nudum), flax (Linum usitatissímum), and opium poppy (Papaver somniferum). Further, wild plants would have played a more or less important part in the diet of the Neolithic inhabitants.
Pollen and diatom analysis of a shore section of the former lake Wervershoof1974Voorrips, A.; Jansma, M.J.53(6)A pollen- and diatom analysis of a shore section of the former Lake Wervershoof was carried out to investigate the history of occupation and vegetation in the region. The section is dated to between 1800 BC and 850 AD; a dating near the end of this period is probable. The presence of human occupation near the lake shore is shown. At this time the lake contained fresh water. The occupation changed its agricultural emphasis from the growing of wheat and barley to the growing of rye. The occupation is ended by a marine transgression. During a break in this transgression there is a renewed inhabitation.
Pollen and diatom analysis of a shore section of the former lake Wervershoof1974Voorrips, A.; Jansma, M.J.53(6)Large Enclosure
Palynology in the study of present-day hillslope development1974Riezebos, P.A.; Slotboom, R.T.53(6)It is pointed out that in measuring current geomorphological processes, which in general act either extremely slowly or, if more catastrophic in nature, at long intervals, knowledge of the recent geomorphological history is essential. This is particularly necessary, if the outcome of the measurements have to serve as a basis for prognosis, because an extrapolation of measurements alone is subject to a high degree of uncertainty. In the area near Bavigne (Luxembourg), where present day displacements of slope material are measured, loamy materials covering the slopes appear often to contain pollen in appreciable amounts. Pollen diagrams constructed from this sort of material show a considerable agreement with the corresponding sections of reference diagrams prepared from alluvial deposits. The disturbance of the pollen stratification by the decay of included contemporaneous pollen combined with a supply of younger pollen, which is considered to be common in sandy soils, apparently has been equally effective in the alluvial fills and in the soils developed in the slope-covering materials. Hence, the disturbance must have been of a similar order of magnitude in the alluvial as well as in the slope materials. The present authors therefore consider the palynological analysis under certain circumstances as an appropriate technique for collecting the necessary information in regolithic materials. The data obtained suggest that pollen analysis of these materials, in conjunction with lithological and pedological field evidence, not only may be used to date events, to which slope materials have been subjected in the recent past, but also to contribute to their reconstruction.
Palynology in the study of present-day hillslope development1974Riezebos, P.A.; Slotboom, R.T.53(6)Large Enclosure
Problems in the interpretation of pollen diagrams of mineral soils1974Havinga, A.J.53(6)The theories of pollen homogenization and of differential decay of Quercus pollen in Pleistocene cover sand soils now showing a podzol profile, adduced in earlier papers, are disputed by some palynologists. In the present article they are supported by various palynological, ecological, pedological and experimental arguments. Two examples from published evidence, relating to a loess and a cover sand soil respectively, are given to demonstrate that pollen analysis of mineral deposits with a minute pollen concentration may easily lead to the wrong conclusions.
The data bank of palynological species descriptions at Leiden1974Gemeraad, J.H.53(6)The present state of the palynological data bank at Leiden is described, the problems, as yet partly unsolved, are explained and suggestions are given to improve the input procedure.
The Northwest European pollen flora, a new project1974Janssen, C.R.; Punt, W.; Reitsma, T.J.53(6)
Committee "Geoscience and man"197453(6)
The Calais deposits in the vicinity of Wieringen and the geogenesis of Northern North Holland1975Ente, P.J.; Zagwijn, W.H.; Mook, W.G.54(1-2)Based upon lithologic data and radiocarbon datings the lithostratigraphy of the Calais IV phase and existing subphases A and B is discussed. A subdivision of the Calais IV A subphase into two subunits 1 and, 2 is introduced. The new subdivision solves the incompatibility between statements of various previous authors on the subject. The data obtained are utilized to elucidate the genesis of northern North Holland.
Continental and coastal plain deposits of the uppermost Old Red Sandstone complex of Southern Ireland1975Kuijpers, E.P.54(1-2)A description is given of an Old Red Sandstone sequence of Upper Devonian age occurring along the south coast of Ireland. This sequence shows a gradual transition from continental deposits to overlying tidal marine sediments via a transition zone. The most characteristic changes occurring upward in the transition-zone between the underlying continental (interior alluvial plain) deposits and the marine tidal sediments are: 1) The increasing mineralogical maturity of the sandstones. 2) The appearance of "heterolithic beds". 3) The increasing frequency of occurrence of thick fluviatile sandstones. 4) The change in rock colours from reddish via greenish to greyish hues.
Spilites, regional metamorphism and subduction in the Iberian Pyrite Belt: some somments1975Schermerhorn, L.J.G.54(1-2)The Devonian-Lower Carboniferous eugeosynclinal succession of the lberian Pyrite Belt was deformed and regionally metamorphosed during the Hercynian orogeny. Metamorphic grade decreases from lower greenschist facies in the north to pumpellyite facies in the south. The volcanics comprise a felsic and a mafic-intermediate suite, the latter including spilite lavas and tuffs with intrusive diabases. Spilites precede, follow, and are contemporaneous with felsic eruptions. The parent magma of the spilites and albite diabases was not altered notably by contamination and assimilation. The felsic volcanics are sodic to potassic quartz keratophyres, mostly tuffs. Rio Tinto stratigraphy is reviewed. The possibility that the compositional bimodality of the volcanics might be related to subduction seems remote.
Allophane and its initial crystallization products as concretions in the south Limburg Chalk1975Buurman, P.; Boekschoten, G.J.; Koster, Y.54(1-2)Silicon-alumina concretions with about equal amounts of both components and ranging in crystallinity between allophane and initial crystallization toward halloysite or gibbsite were found in and on Upper Cretaceous limestones. These concretions were probably the result of accumulation of Late Tertiary and Early Pleistocene weathering products, accumulated by stagnation of percolating waters. Crystallization might have been inhibited by the electrolyte concentrations in the limestone pore waters. pure allophane material was much like the allophane originally described in 1816.
De Nederlandse Aardwetenschappen in de spiegel van oraties en openbare lessen1975Engelen, G.B.54(1-2)
Roraima, Tabelberg and Uatumã Formations of the Guiana Shield: a correlation1975Kloosterman, J.B.54(1-2)On the western and central parts of the Guiana Shield, South America, tabular sedimentary sequences are found, consisting of sandstones, shales and conglomerates and of tuffs, tuffites and graywackes. In Venezuela, Guyana, Roraima and Surinam they have been designated the Roraima Formation; on the southern margin of the Guiana Shield in Brazil they are called the Uatumã Formation. The writer argues that they are similar in origin and probably are roughly coeval in the several parts of the Shield. Summaries and a selection of quotations are presented, in part taken from not easily available papers, and in part translated for the benefit of students who read English but not Portuguese.
Isotope geochronology in the Indonesian Tin Belt1975Priem, H.N.A.; Boelrijk, N.A.I.M.; Bon, E.H.; Hebeda, E.H.; Verdurmen, E.A.T.; Verschure, R.H.54(1-2)Granitic rocks on Belitung (Billiton), Bangka and the Tuju islands (Pulau Tudjuh) have a Rb-Sr isochron age of 217 ± 5 Ma with initial 87/Sr86Sr = 0.7152 ± 0.0029 (15 whole-rocks and 4 biotites). K-Ar ages of four hornblendes and two biotites average 214 ± 4 Ma. The granitic complex on Karimata has a Rb-Sr isochron age of 74 ± 2 Ma with initial 87Sr/86Sr = 0.7101 ± 0.0025 (8 whole-rocks), while an associated amphibolite has a K-Ar age of 78 ± 5 Ma. (Rb-Sr ages based upon d = 1.39 x 10-11/a; errors at 95% confidence level.) The granites have intruded into flysch-type sediments containing Norian fossils, while the regional stratigraphic and tectonic relationships strongly suggest that they are overlain by fossiliferous sediments of probably Rhaetian age. The age of 217 ± 5 Ma can thus be taken as the minimum age of the Norian, probably as representing the Norian/Rhaetian boundary. Cassiterite mineralisation is associated with both Upper Cretaceous and Upper Triassic granitic masses, but major tin deposits are related only to Upper Triassic plutons.
Kritik zur plattentektonik1975Bemmelen, R.W. van54(1-2)For an all-round interpretation of the Earth's history geodynamic as well as geochemical processes should be taken into account. The anthropomorphic character of the jargon used by plate-tectonicists is an impediment to achieve this aim. The driving forces of the geodynamic evolution as viewed by the current model of plate tectonics are too much restricted to mechanical processes, whereas their intertwining with physico-chemical processes should also be realized.
Ice-pushed ridges in the Eastern part on the Netherlands river area1975Verbraeck, A.54(1-2)
The Pre-Tertiary rocks of SW Cyprus1975Ealey, P.J.; Knox, G.J.54(1-2)The pre-Tertiary rocks of SW Cyprus consist of an autochthonous unit, composed of Campanian sediments, and an allochthonous assemblage containing igneous and sedimentary rocks of Triassic to Lower Cretaceous age, and some undated metamorphic rocks. The complex rests on a basement of Cenonanian to Campanian basic pillow lavas, which form the youngest unit of the Troodos Igneous Complex. The basal autochthonous sediments (Perapedhi Formation) consist of thin (less than 10 m) iron-rich shales (umbers), locally associated with cherts and manganese nodules. The overlying autochthonous sediments (Kannaviou Formation) comprise 500 m or more of abyssal mudstones and marls intercalated with tuffaceous sandstones containing also lithoclasts similar in lithology to the large allochthonous rock units that are now referred to as "Mamonia Allochthonous Complex" The volcanic elements in the Kannaviou Formation have been derived from an andesitic-dacitic source, extraneous to Troodos, and probably reflect the crustal instability that culminated in the emplacement of the Mamonia Allochthonous Complex. During this time the Troodos Massif was probably a submarine high, undergoing submarine weathering and local brecciation. The Mamonia Allochthonous Complex comprises Triassic alkali lavas associated with reef and pelagic limestones, metamorphic schists, serpentinites, peridotites, gabbros, Triassic turbiditic sandstones and packstones intercalated with shales, Jurassic cherts, shales and packstones, and Lower Cretaceous quartz sandstones intercalated in shales. The total sedimentary thickness is not more than a few hundred metres. The association is interpreted to be of deep-marine origin in general, but including also shallower, probably continental-margin related elements at its base and top. The allochthonous units were probably emplaced on southern Cyprus as olistolithic blocks or smallscale sheets, and as debris in Campanian-pre-Upper Maastrichtian times. Their regional distribution in Cyprus makes a proveance north of Troodos unlikely
in vitro weathering products of pyrite1975Buurman, P.54(1-2)Fine grained natural pyrite concretions oxidize spontaneously under laboratory conditions. A solution of oxidation products in distilled water yields the following crystallization products upon evaporation (in order of formation): melanterite, rozenite, szomolnokite, rhomboclase, coquimbite, roemerite, a slightly basic ferric sulphate, and voltaite. The crystallization sequence is comparable to that found in natural environments where pyrite ores are oxidizing.
In memoriam prof. Dr. Ir.F.A. van Baren1975Reynders, J.J.; Mouthaan, W.L.P.J.54(3-4)
Jaarrede1975Eek, W.N. van54(3-4)
Late Quaternary history of the Skagerrak; an interpretation of acoustical profiles1975Weering, T.C.E. van54(3-4)In the Skagerrak several sedimentary units are present that were found previously in the Norwegian Channel. The thickness and distribution of late-postglacial sediments is measured and mapped. The origin of the sediments are discussed and a model for the late-Quaternary sedimentary history of the area is suggested. The occurrence of shadow zones is related to gasbubbles or coarse materials in the subsoil. Sedimentary structures such as large scale foresets and giant sand waves are found along the southern border of the Skagerrak. The sand waves are considered as relict structures. The bottom relief in the Skagerrak is closely related to the sedimentary history; along the southern border ice grounding has probably played an important role.
Fossil coleoptera from Weichselian deposits at Voorthuizen, the Netherlands1975Angus, R.B.54(3-4)An account is given of fossil from two organic layers in Weischelian deposits at Voorthuizen, The Netherlands. On radiocarbon and stratigraphic evidence these beds apparently date from between the Brorup and Upton Warren interstadials. Although the samples analysed were small and gave meagre fossil assemblages, the lower bed clearly represents tundra conditions, with average July temperatures below 10°C. The upper bed gave a climatically nondescript fauna from which no firm inferences can be made. However, it is considered that had this bed been deposited under conditions as cold as those represented by the lower bed, the fossils would have given some indication of this, and it therefore seems likely that it reflects somewhat warmer conditions, with average July temperatures of about 10°C
Cementation of pliocene-Quaternary fluviatile clastic deposits in and along the Oman mountains1975Stalder, P.J.54(3-4)Huge masses of coarse clastics were deposited and cemented during and shortly after the last uplift phases of the Oman Mountains; the environment was fluviatile and the climate was alternatively humid and semi-arid. The cement includes mainly calcite, high-magnesium calcite and dolomite; their genesis and relation to the area of water run off are discussed. The cement textures indicate both vadose and phreatic cementation. The absence of cement cathode-luminescence seems to be characteristic of this fresh-water environment of cementation.
Correlation of Indonesian active volcanic geochemistry with Benioff Zone Depth1975Hutchison, C.S.54(3-4)The active volcanic arc of Indonesia extends almost continuously over 6000 km from north Sumatra to the Molucca Sea. Chemical analyses of 196 rocks from 33 volcanoes have been processed to give molecular norms and multiple linear correlation analyses between various chemical parameters and silicon content or differentiation index (D.I.) and vertical depth of the underlying Benioff Zone, which ranges from 140 to 300 km. The great majority of the volcanic products is of augite-hypersthene andesite or basalt, sometimes with olivine and hornblende, and occasionally with biotite, quartz and tridymite. Leucite occurs in volcanoes overlying the deepest seismic contours. Most rocks are quartz-normative, but many are olivine- and even nepheline-normative where the volcanoes overlie the greatest seismic depths. Significant relationships exist between each of potassium %, alkalis % and the ratio of potassium to alkalis and both silicon content (or D.I.) and depth to the underlying Benioff Zone. The relationship with silicon or D.I. is petrologically controlled and the relationship with Benioff Zone depth may suggest that the magmas are produced at and rise from the Benioff Zone and that some of the chemical variation is controlled by the depth of magma production. However the best correlation obtained cannot explain more than 50 to 60% of the chemical variation in terms of depth of magma production. Future refinement of the measurement of the seismic contours and improvement of the chemical analyses may lead to a closer correlation, but on the basis of the present data it is necessary to conclude that, in addition to seismic depth, other unknown factors play an important role in controlling the chemical variation of the volcanic rocks.
The Triassic Kodiang limestone formation in Kedah, W. Malaysia1975Coo, J.C.M. de; Smit, O.E.54(3-4)The Triassic Kodiang Limestone Formation is formally described as a new lithostratigraphic unit in the Malay Peninsula. The thickness of the stratotype measured is more than 125 m. The carbonate sediments, consisting of algal stromatolites, intraformational breccias, limestone conglomerates with sedimentary slumps, black mudstones with radiolarian chert, and limestone turbidites, were deposited in a shelf, slope, and basinal environment. The paleoslope was dipping to the east.
An interpretation of Groningen subsurface temperature data1975Engen, H. van54(3-4)Temperature surveys have been carried out by NAM in gas wells in and around the Groningen field, From these surveys subsurface temperatures at datum level (= 2,875 m S.S.) between 88 and 1 14° C have been obtained, which have been used to construct a subsurface temperature map. This map is used for volumetric gas in place calculations and the prediction of producing wellhead temperatures. On the map a number of areas with low datum depth temperatures can be seen, which appear to correspond with overlying salt domes and ridges. In these areas the heat flow rate to the surface is found to be above average.
An interpretation of South-Limburg subsurface temperature data1975Sadée, C.P.M.54(3-4)Staatsmijnen in Limburg (now named Naamloze Vennootschap DSM at Heerlen) has conducted temperature measurements in the Carboniferous rocks of the South-Limburg coalmining area. From the measuring results the temperature gradients for both the overburden and the Carboniferous are derived. The temperature gradient of the Carboniferous averages δc = 3.0 °C/100 m, whilst, that of the overburden, depending on the composition and the water content, appears to range between δd = 5.5 and δd = 2,4 °C/100 m, according to 5 separate regional groups of measurements in the South-Limburg mining area. With the aid of the data obtained a map has been compiled of subsurface temperature at datum level, (-749 m. Amsterdam Zero Level), which chart is to serve in making predictions regarding climatic conditions in underground workings.
The relation between the tropical planktonic foraminiferal zoantion and the Tertiary far East letter classification1975Haak, R.; Postuma, J.A.54(3-4)A correlation between the tropical planktonic foraminiferal zonation and the Tertiary Far East Letter Classification is presented. Their relationships with world-wide time stratigraphical units and classic European stages are tabulated. The datum planes of the most important planktonic and larger Foraminifera are also shown.
The sheeted intrusive complex of Troodos, Cyprus1975Boorder, H. de54(3-4)Geological observations during a mineral exploration programme in the western part of the Troodos Igneous Complex, Cyprus, have led to the formulation of a hypothesis concerning the origin of the Sheeted Intrusive Complex in connection with the development of the Troodos dome. The hypothesis suggests an originally horizontal attitude of the "Diabase" sheets in a large part of the Sheeted Complex. Some related aspects of sulphide mineralisation are discussed.
Isotopic dating of glauconites from the Upper Cretaceous in the Netherlands and Belgian Limburg, 11975Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Romein, B.J.; Verdurmen, E.A.T.; Verschure, R.H.54(3-4)K-Ar dates of seven glauconites from Campanian and Maastrichtian horizons in Netherlands and Belgian Limburg are ionsistent with their stratigraphical position.
Structural evolution of the Neogene salt basins in the Eastern Mediterranean and the Red Sea1975Mulder, C.J.; Lehner, P.; Allen, D.C.K.54(3-4)This paper attempts to describe the Neogene evaporite basins in the Eastern Mediterranean and the Red Sea Rift in the context of the regional tectonic framework and the regional tectonic phases of the Alpine-Mediterranean region. It is mainly based on airgun seismic surveys in the Mediterranean and Red Sea carried out in the time span between 1971 and 1973. The Neogene basins of the Eastern Mediterranean as well as the Red Sea began to form after the main Oligocene - Lower Miocene Alpine orogenic phase. The morphological conditions for evaporite deposition in the Mediterranean basins, during a short period of time were provided by late Miocene - early Pliocene tectonic movements in the basin peripheries, which caused a temporary restricted connection with the open sea. It was followed by open marine conditions during the Pliocene. Graben subsidence in the Red Sea Rift began during Oligocene - early Miocene. Initial terrestrial sedimentation was followed by widespread evaporite deposition, which lasted throughout a considerable part of the Miocene period. The late Miocene - early Pliocene tectonic phase caused a final disruption of the connection with the Mediterranean. Open marine conditions were established in the Pliocene through a connection with the Indian Ocean. Regional doming of the Arabian-Nubian shield and axial collapse, first of the main graben and later of the axial trough, is thought to represent the dominant mechanism for the origin of the Red Sea Rift.
A pollendiagram from the Weichselian deposits near Apeldoorn, the Netherlands1975Ruiter, G. de54(3-4)Pollen analysis of a 20 m long core of peat, sand and silt deposits near Apeldoorn, the Netherlands shows that these sediments were laid down in the Late Eemian, the Early Weichselian and the Middle Weichselian. Only the most upper Eemian is present- In the Early Weichselian one zone with interstadial character and represented by a peat layer is particularly well developped, showing succesive maxima in the pollen values of Alnus, Picea and Pinus. Pollen of Betula however remains dominant. The Middle Weichselian is strongly glacial in character. It includes an oscillation with Salix, Potamogeton, Pediastrum and SeIaginella selaginoïdes pointing to more favourable conditions.
A pollendiagram from the Weichselian deposits near Apeldoorn, the Netherlands1975Ruiter, G. de54(3-4)Large Enclosure
In memoriam William van Leckwijck (1902-1975)197655(1-2)
Commentaires sur la datation des glauconies du Cretace superieur du Limbourg1976Odin, G.S.55(1-2)
Isotopic dating of glauconites from the Upper Cretaceous in the Netherlands and Belgian Limburg, 1: reply to the comments by G.S. Odin.1976Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Romein, B.J.; Verdurmen, E.A.T.; Verschure, R.H.55(1-2)
On the origin of submarine canyons1976Berckel, F.L. van55(1-2)It is suggested that the origin of submarine canyons depends on two factors: 1. a drop of the ocean level below the shelf/slope rim as a consequence of the formation of enormous ice masses during a glaciation. 2. the presence of powerful streams, created by the melting of ice masses; these streams carried large amounts of glacial debris across the shelf and deposited them on the continental slope. Continuous overloading of these debris piles resulted in debris avalanches downslope, which excavated canyons and ultimately formed large submarine fans.
Marine transgressions as a factor in the formation of sandwave complexes1976Swie-Djin, N.55(1-2)The genetic relation between the onset of a marine transgression and the consequent upbuilding of three ancient sandwave complexes is discussed and illustrated. These are: a. The Lower Tertiary Roda sandwave complex of the southern Pyrenean basin. b. The Lower Greensand sandwave complex of the Isle of Wight. c. The Miocene sandwave complex of the swiss Molasse. Based on these examples, a model for the formation of a sandwave complex in relation to a marine transgression and tidal action is developed. Finally, based on geological arguments derived from the sequential and structural analysis of these ancient sandwave complexes, the genesis of the modern sandwaves of the North Sea is ¡elated to the Holocene transgression.
Thermal anisotropy - a factor contributing to the distribution of Caledonian metamorphic zones in the SW Scottish Highlands?1976Borradaile, G.J.55(1-2)The distribution of metamorphic zones in the SW Scottish Highlands may have been influenced by the bulk thermal anisotropy of the regional structure
Models for the estimation of world ore reserves1976Wijs, H.J. de55(1-2)Although mineral resources are non-renewable, mineral reserves can be created by new discoveries and from already identified sub-economic resources. A probabilistic model is presented to adjust reserve estimates to changes in minimum workable grade. This model is based upon a rational frequency distribution for the dependence of tonnage on cut-off and average grade. For this purpose the straight lognormal transformation is rejected, and replaced by a logarithmic, three-parameter transformation of wider applicability, including negatively skewed distributions of iron, bauxite, and phosphate deposits. The estimation of ore reserves occasionally serves the restricted purpose of the commercial evaluation of mining property. Yet, more often such estimates have a wider scope: up to forecasts of the adequacy to supply the future needs of a country or the world.
An inexpensive infinite flume1976Winkelmolen, A.M.55(1-2)A new design is presented of an infinite flume. This flume has been specially developed to study equilibrium processes during transport and deposition of sand and the influence of time on these processes. The flume-plan is oblong rectangular, the channel is 60 cm deep and 45 cm wide. In each corner reflexion blades are mounted, which are specially shaped to compensate for the increase in width in the bends. The water drive is performed by means of paddles, hanging from two parallel chains which run over cog-wheels. The paddles move in a vertical position through the water. Due to a downcurrent inclination of the chains, the paddles are gradually lifted out of the water and are free of the surface whilst flipping round the cog-wheels, thus producing no extra turbulence. Flow characteristic are shown for different discharge rates and peculiars of the flume are discussed
Lineament analysis from ERTS (Landsat) images of the Netherlands1976Sesören, A.55(1-2)A lineament map from ERTS (Landsat) images of The Netherlands is presented. The directions of these lineaments have been compared to fault patterns in the Carboniferous, the base of the Cretaceous and the uppermost Tertiary and Quaternary. The known fault patterns are essentially similar to the Landsat lineament patterns
Preliminary observations on the origin and sedimentological nature of sarsen stones1976Whalley, W.B.; Chartres, C.J.55(1-2)The type of orthoquartzite known as sarsen stone is found over wide areas above the Chalk of south-east England. Scanning electron microscope and thin section studies indicate that sarsens are composed of quartz grains with syntaxial overgrowths of secondary quartz. They contain relatively little inter-particle siliceous cement. Their strength appears to be derived from the interlocking structure of the quartz grains produced by the syntaxial overgrowths.
Eolian "sandy lignite" and associated sediments from the Miocene of the Lower Rhine Basin Western Germany1976Clemmensen, L.B.55(1-2)Eolian flats are often encountered along modern shorelines in association with wash-over fans, storm inlets and swamps. A possible ancient analogy to this environmental situation has been confronted in the Miocene sediments in the Garsdorf Quarry, Western Germany. These sediments consist of several facies associations, the uppermost of which is notable due to the occurrence of sandy lignite. The sandy lignite displays several sedimentary structures of presumably eolian origin and is interpreted as an eolian sediment formed during humid conditions on eolian flats. Deposits associated with the sandy lignite include stratified channel-sand, most probably representing storm inlets filled by eolian and ephemeral stream deposits, sheets of faintly laminated sand of wash-over fan origin, and lignite formed in coastal swamps.
Practical applicability of a zonation with benthonic foraminifera in the worldwide Lower Cretaceous1976Bartenstein, H.55(1-2)Presentation of a new zonation chart with benthonic foraminifera, valid for the worldwide Lower Cretaceous, Berriasian to Albian, in the temperate and tethyan facies realms. Divisions, sections and zones comprise 22 foraminifera columns with 36 species of different stratigraphic value.
Size, shape and density sorting around two barrier islands along the north coast of Holland1976Veenstra, H.J.; Winkelmolen, A.M.55(1-2)The sand movement on and around two barrier islands flanking the tidal flat area north of The Netherlands is studied by means of size, shape and density sorting. Since there is mainly fine sand in the area, the competency of the transporting media is seldom reached and selection mainly occurs on shape and density. In the deeper off-shore, a coarse grain-population shows inherited characteristics from a higher energy early transgressive phase, whereas a finer population is consistent with the present-day hydrodynamic situation. Tidal channels in between the islands form outer tidal deltas. These deltas protect the islands against the waves produced by N-W gales and they form a "shadow" for the W-E longshore currents. The coastline of the islands is still retreating. The removal of sand mainly occurs during storm surges. The eroded material is redeposited in sorted zones parallel to the coast. Only the susceptible material, that is deposited farthest from the beach, can be transported by the longshore currents. The coarsest, most spherical and densest grains remain closest to the beach and can re-enter the beach as prograding bars during more quiet conditions. This process gives rise to a stepwise diminishing grain-size from island to island towards the east. The eastern island is situated on top of older river and/or tidal channel deposits, which are easy to erode. This gives the tidal inlet, and hence the tidal delta, a great lateral mobility. The eastern island is therefore very mobile. The western island is bordered by a deep tidal channel, which cuts into more resistent glacial deposits. This keeps the channel and hence its outer tidal delta in the same site. The western island therefore did not change longitude and constantly retired over its own deposits. This resulted into completely different sand properties for both islands, which mainly shows in the garnet percentages and the high rollability values for the western island.
Simple uses of covariograms in geology1976Dijkstra, S.55(1-2)The paper presents an elementary introduction into the theory of random functions and demonstrates the usefulness of covariograms in the analysis of geological data. Most examples refer to experiences in exploration geochemistry.
Clay diapirism in the Lower Emsian La Vid shales near Colle, Cantabrian mountains, NW-Spain1976Stel, J.H.55(1-2)Faults, tension-rupture, slumplike- and load-and-flamelike structures in thin carbonate intercalations in the Upper La Vid (Lower Emsian) shales NW of Colle are described. They are argued to have been caused or accentuated by clay diapirism. The paleoslope probably had no influence on this deformation process.
Major Flandrian transgressive cycles, sedimentation and palaeogeography in the coastal zone of Essex, England1976Greensmith, J.T.; Tucker, E.V.55(3-4)The 36 m thick succession rests discordantly on sub-aerially weathered Pleistocene and older strata arid comprises 3 major marine transgressive cycles. The lower 2 are confined to the vicinity of deep Pleistocene channels whereas the 3rd, possibly initiated c. 7500 B.P. extends across the whole coastal zone. Each cycle consists of a lower division of clays and silts with thin coarser deposits towards the base and an upper division of sands and sandy gravels. The contact between the two divisions is often erosional or sharp. Landward displacement of the plain lithofacies is most pronounced during episodes of relatively rapid rise in sea level, as in the U.S.A. and Holland. At certain levels reached by the rising sea extensive bodies of relict Pleistocene sediment becamte available for marine reworking. The persistence of lagoon, marsh, beach, chenier, barrier, tidal flat and channel lithotopes through the succession in conjunction with 12 radiocarbon dates allow general palaeogeographic deductions to be drawn, more especially for c. 7500, c.4000 and c. 1350 B.P.
Morphogenetic trend of Lepidocyclina and its application in time stratigraphy1976Kiam Fui, H.55(3-4)The morphogenetic trend of Lepidocyclina in Miocene sediments from Sarawak, East Malaysia, has been studied. A correlation has been established between the degree of curvature of Lepidocyclina and the planktonic foraminiferal zonation in the area. The results prove that this evolutionary trend of Lepidocyclina is a practical tool for chronostratigraphy.
The distribution of Laacher See ash west of the Eifel region1976Jungerius, P.D.; Riezebos, P.A.55(3-4)Volcanic grain percentages in heavy-mineral concentrates of local colluvial deposits in Luxembourg and surrounding areas have been used to trace the dispersal of an ash deposit of Allerød age characterized by an association of brown anphibole, pyroxene and sphene. Remnants of the ash fall were detected at distances of more than 300 km southwest of the Laacher See eruption centre. As Allerød ashes previously have been found at similar distances east of this centre, it is evident that the dominant wind direction during this geological interstade cannot be reconstructed from the distribution of ashes produced by short-lived eruptions.
On the solenid growth habit of Paleofavosites1976Stel, J.H.; Oekentorp, K.55(3-4)Serial sections of Paleofavosites specimen presents proof to the contention that Desmidopora = Multisolenia is only a growth habit of Paleofavosites. The socalled solenia are funnel-shaped parts of the paleofavosited wall around quite ordinary corner pores. The former are arranged in dumb-bell pairs among any tour adjoining corallites. Such dumb-bells are arranged crosslike, when seen in the direction of growth of the corallites. This growth habit is found in the type species of Paleofavosites as well as in other undisputed members of that genus. The present authors accordingly consider Priscosolenia as a junior synonym of Paleofavosites. Desmidopora (= Multisolenia + Mesosolenia) could serve as a subgeneric heading for paleofavositids with this peculiar growth habit.
Implications of the occurrence of large gravity gradients in Northern Timor1976Milsom, J.; Richardson, A.55(3-4)Recent gravity measurements in eastern Timor have shown that steep gradients occur in the northern part of the island, and that the maximum Bouguer Anomaly values attained are greater than those on the inner volcanic arc immediately to the north. The observations can be explained only by supposing that the dense source rocks rise very close to the surface, and analogies can be drawn with the large anomalies associated with ophiolitic thrusts in New Guinea and New Caledonia. The pattern of volcanic activity north of Timor also resembles that of eastern New Guinea, suggesting, again by analogy, that a thrust slice is wedged in the subduction zone south of the inner Banda arc. If correct, this hypothesis provides some support for the concept of Timor as built up of a series of thrust slices resting ultimately on continental basement.
Cretaceous oceanic anoxic events: causes and consequences1976Schlanger, S.O.; Jenkyns, H.C.55(3-4)Organic carbon-rich sediments ate globally developed in pelagic sedimentary sequences of Aptian-Albian and Cenomanian-Turonian age. They formed in a variety of paleo-bathymetric settings including oceanic plateaus and basins, continental margins and shelf seas. The widespread nature of these deposits suggests that they were not strictly controlled by local basin geometry but were a product of "Oceanic Anoxic Events". We interpret these events as the result of the interplay of two major geologic and climatic factors: firstly the Late Cretaceous transgression which increased the area and volume of shallow epicontinental and marginal seas and was accompanied by an increase in the production of organic carbon; and secondly the existence of an equable global climate which reduced the supply of cold oxygenated bottom water to the world ocean. This combination of climatic and hypsographic conditions favoured the formation of an expanded oxygen-minimum layer and where this intersected the sediment-water interface, organic carbon-rich deposits could be formed, these being records of "Oceanic Anoxic Events".
Critical parameters for the production depletion and substitution of mineral resources1976Brinck, J.W.55(3-4)From the mining history of different mineral commodities it is indicated that the average annual growth of production can be used as an indicator for their economic and industrial maturity. Calculations show the growth rate to be determined by the size of the remaining reserves as function of the annual production. Its value at all times tends to remain directly proportional to the number of times that a mineral industry could double its annual production before depleting its remaining reserves. The observations indicate logistic growth of mineral production toward a moving ceiling which is determined by both natural- (Clarke and specific mineralisability) and technico-economic- (price and current state of mining technology) parameters. If confirmed, this will enable the prediction of ultimate production levels and possible rates of substitution of scarce commodities by more abundant ones. Furthermore, it would increase the physical base for the viability of our technological society by a factor greater than 10; increasing its predictable lifetime from less than a century to well over a thousand years. Using this relation to predict the size of the inferred reserves of a metal from its current annual production and average growth rate, close confirmation of independent estimates with the Mimic model is obtained for the major metals iron, aluminum, copper, gold, zinc and lead, each with a value of annual production in excess of one billion US$. Somewhat less convincing results are obtained for the almost equally well established industries of nickel, tin, mercury and antimony. They show lower growth rates than allowed by the theory. Still lower rates are found for the metals chromium, manganese and tungsten. The nonconforming metals all are commodities for which the USA territory shows marked deficiencies. Their less than normal growth seems to stress the importance of geographic and geo-political factors for the industrial development of mineral commodities, as well as their rather great substitutability.
Fan-delta sedimentation: An example from the Late Jurassic - Early Cretaceous of Milne land, Central East Greenland1976Sykes, R.M.; Brand, R.P.55(3-4)The Hartz Fjeld Formation (Middle Volgian - Ryazanian) is interpreted as a synorogenic fan-delta complex. The lower part of the formation is characterised by coarsening upwards fan-delta sequences with marine delta destructive units. A thick lagoonal unit separates these sequences from the upper part of the formation in which fan-delta deposition resumed in a lateral position and fan plain sands are intercalated within bay muds. A distinction is made between fan-delta deposition, dominated by sheetflood and streamflood processes, and short-headed stream delta deposition in which flow is confined in stable channels.
Volcanism and metallogenesis1976Schermerhorn, L.J.G.55(3-4)
Zum alter des "Karbons vom Christophberg", Kärnten, Österreich1976Amerom, H.W.J. van; Boersma, M.; Riehl-Herwirsch, G.55(3-4)In 1961 during fieldwork plant remains were found at the "Christophberg" near St. Filippen (Carinthia, Austria). The flora was believed to be indicative of a Westphalian age. However, during the summers of 1974 and 1975 additional material has been collected, among which Callipteris conferta could be determined. Due to the discovery this flora at the base of the postvariscian transgression series at the Christophberg is at present considered to be of Rotliegend age.
Charles Lyell and Charles Darwin1976Brouwer, A.55(3-4)Lyell's main work, The principles of geology (1830-1833), left a deep impression on Darwin. This is not only evident from the three geological books Darwin published after his return from the voyage of the Beagle, but also from his main work, The origin of species (1859). The latter can be considered as an application of Lyell's principle of uniformitarianism to the history of the living world. Lyell on the other hand never became a fully convinced Darwinian. It is suggested that this was mainly due to a fundamental difference between Lyell's steady-state model of the Earth's history, and Darwin's view of the history of life as a progressive process. Increased knowledge of the Earth's early Cryptozoic history shows that progressive changes also occurred in the history of the Earth. This, however, does not invalidate the general applicability of the principle of uniformitarianism throughout the whole of geological time.
Notes on the sedimentology and paleobotany of the Werfener schichten in the Western Gailtaler Alps near Kötschach (Carinthia, Austria)1976Amerom, H.W.J. van; Boersma, M.; Niedermayr, G.55(3-4)During fieldwork near Kötschach in Carinthia (Austria) in the summer of 1975 plant remains in the "Werfener Schichten" (Trias) were discovered for the first time, Pleuromeia cf. sternbergii (Muenster) Corda, Voltzia sp., "roots", "seeds" and some leave fragments of uncertain identity could be recognized. The plant-bearing beds are situated in between a series of red and gray coloured, mainly coarse-grained clastics, from which important indications could be obtained on the lithological development of the triassic basal layers in the western Drauzug.
Inflatie in de stratigrafie?1976Brouwer, A.55(3-4)It is questioned whether the complete system of lithostratigraphic terms introduced in the explanation of a (beautiful) new geological map of the Netherlands, scale 1:600000 (Zagwijn & van Staalduinen, 1975) serves a useful purpose. Some definitions seem to be in defiance of the recommendations by the International subcommission on stratigraphic classification, some terms seem to be superfluous.
In memoriam Ph.H. Kuenen1977Straaten, L.M.J.U. van56(1)
Features of Middle Pleistocene sandur deposits in the Netherlands1977Ruegg, G.H.J.56(1)The sandur deposits discussed below appear to be much similar to alluvial fan deposits. Only minor differences may occur which are related to the nature of the source area (slopes, availability of non-consolidated material) and to climatic conditions. In the introduction a synopsis is given concerning river types and their deposits in general, represented in the deposits of this part of the North Sea Basin; subsequently, Neogene and Quaternary fluvial deposits (including sandur deposits) in The Netherlands are classified based on the type of deposition.
Depositional environment of the Oligocene Rupel Clay in well Grashoek-l, Peel region, The Netherlands.1977Brouwer, J.56(1)A continuously cored marine Oligocene Rupel Clay of the N.A.M. well Grashoek-1 (Peel region, the Netherlands) yielded a benthonic foraminiferal fauna indicative of a bathyal environment with a seadepth below 300-500 m.
Depositional environment of the Oligocene Rupel Clay in well Grashoek-l, Peel region, The Netherlands.1977Brouwer, J.56(1)Large Enclosure
A volumetric model to estimate the amount of gas in a newly discovered rock reservoir.1977Prins, S.56(1)A volumetric calculation of the amount of gas in a rock reservoir requires in practice numerical integration of a volume integral. The distributions of porosity- and gassaturation values throughout the reservoir have then to be known: Since in all practical cases these distributions are only partially known, the calculatiorì of the amount of gas in the reservoir can only be made using a model of the reservoir from which the overall distributions are derived. The model is based on premises that have to be specified separately. The problem of finding suitable distributions is most urgent for a newly discovered reservoir. Therefore an example of such a case has been picked out and general geological and physical considerations have been used as the principal premises in order to arrive at a starting model, named the Continuous Conformal Model (CCM). The construction and computational procedures are illustrated by a numerical example.
Biostratigraphy of Cretaceous calcareous nannoplankton1977Sissingh, W.56(1)The stratigraphical distribution of selected species of calcareous nannoplankton from sections of Cretaceous deposits in Tunisia, France, The Netherlands, West Germany, Great Britain, Denmark, Turkey, Oman and New Jersey was studied. A number of Late Cretaceous lineages was recognised, on which a proposal for a revised zonation is based. Twenty-six zones are distinguished for the Cretaceous interval. First-order correlations between zones and Cretaceous stage-stratotypes are discussed briefly. The Upper Cretaceous part of the proposed zonation has also been correlated with planktonic foraminiferal zones. One new genus and two new species are described.
Biostratigraphy of Cretaceous calcareous nannoplankton1977Sissingh, W.56(1)Large Enclosure
The geology of Cyprus and its place in the East-Mediterranean framework1977Cleintuar, M.R.; Knox, G.J.; Ealey, P.J.56(1)New datings and sedimentological observations seem to confirm the Cretaceous age and submarine origin of the Troodos igneous complex in central Cyprus. Troodos rocks, of marked calc-alkali character, form the basement to an Upper Maastrichtian-Tertiary sequence, 500-1800m thick, of bathyal-shallow abyssal marls and chalks. In N Cyprus these relatively undisturbed sediments are in contact with southward thrusted flysch deposits (2000-3000 m) of prevailing Miocene age, indicating a tectonic weld of major order. Allochthonous Permian-Lower Cretaceous shelf limestones are exposed in what seems to be the core (Kyrenia Range) of the N Cyprus thrust belt. In SW and S Cyprus a thin, exotic rock complex (Mamonia) wedges in between the Upper Maastrichtian-Tertiary sediments and Troodos basement. The Mamonia comprises a Triassic- Lower Cretaceous allochthonous, mainly deep marine assemblage that rests on Campanian dated andesitic pyroclastics. The geological evolution of Cyprus is conceived by the authors as follows: The Troodos igneous complex formed part of an ocean rise in a Cretaceous sea bordered by continental margins. In about Campanian time Troodos was underthrust by the southern (Afro-Arabian) margin. Some of the continental margin rocks (the allochthonous Mamonia), preceded by pyroclastic slope deposits, came to rest on the leading edge of Troodos. The andesitic source of the pyroclastics was probably in the former margin. Quartz sandstone blocks of Lower cretaceous age, included in the allochthonous assemblage, are possibly Nubian sandstones derived from the southern continent. Continued underthrusting forced Troodos to rise without disturbing its sedimentary cover. Eventually, in the upper Miocene and Pliocene, slope deposits and detached shelf limestones from a northern(? ) source were thrust on the Troodos north flank. The tectonic setting of Cyprus is analogous to that of other peri-Arabian thrust belts in that ophiolite/deep-sea sediment associations appear thrown on the southern continent. The Troodos "ophiolite", however, seems unique because of its enormous size and relative rigidity.
A note on the isotopic age of Beryl pegmatites near Rama, Suriname1977Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verdurmen, E.A.T.; Verschure, R.H.56(1)
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)A palynological study has been made of some organic deposits from The Netherlands dated between ca. 50,000 and 30,000 B.P. From the recent ecology and distribution of plants found as fossils in the Moershoofd lnterstadial complex, the Hengelo Interstadial and the Denekamp Interstadial, it was concluded that the average July temperatures were 13°, 13-15° and 10°C, respectively. Furthermore a decrease of at least 5°C was found within a time span of 1,500 years during the Moershoofd Interstadial complex.
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E1
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E2
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E3
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E4
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E5
A palynological investigation of the Moershoofd, Hengelo, and Denekamp interstadials in the Netherlands1977Kolstrup, E.; Wijmstra, T.A.56(2)Large Enclosure E6
The stream network in the Netherlands as a groundwater discharge phenomenon1977Vries, J.J. de56(2)The stream network in the higher, Pleistocene part of The Netherlands is genetically coupled with groundwater discharge systems of various extents. Streams of a given order can be described as the outcrops of groundwater flow systems of a corresponding order. The drainage system is controlled by the precipitation surplus (climate), by the resistance of the subsurface to groundwater flow (geology) and by the previous relief and the depth of incision (topography). This concept is defined as the Groundwater Outcrop-Erosion Model (GOEM). On the basis of this model stream nets can be synthesized theoretically. In this context use is made of data on geology, geomorphology and climate applying groundwater flow formulae and Horton's law of stream order versus stream density. Comparison of the actual and "synthetic" stream-net characteristics shows reasonable agreement.
Contribution to the stratigraphy of the Weichsel Pleniglacial in the Belgian Coversand area1977Vandenberghe, J.; Gullentops, F.56(2)Earlier stratigraphical studies of the upper Quaternary in N.W. Belgium have been supplemented with some recently obtained dates, which allowed to make a new approach to construct a more detailed stratigraphical table of the Weichsel Pleniglacial in this region. Between a series of "laminated sands and silts" (undermost part) and a series of "coversands', (uppermost part) an important peat bed was found (Assebroek peat). The pollen spectrum indicates relative warm conditions. A 14 C-date of 30,700 BP was obtained and therefore the peat is correlated with the Arcy-Kesselt interstadial. The overlying "coversands" are characterized by three levels of ice wedges and frost cracks and by one pebble string. The formation of the lowermost level of large deep ice wedges is dated between 26,220 BP and 24,760 BP. It is shown that the severest climatic conditions during the Weichselian started very soon after the Arcy-Kesselt interstadial.
Late Cretaceous and Cenozoic history of Northeastern Brazil1977Mabesoone, J.M.; Rolim, J.L.; Castro, C. de56(2)The late Cretaceous-Cenozoic history of northeastern Brazil is characterized by relief development, correlative sediments and paleosoil profiles. Between Albian and Miocene the so-called Sulamericana Surface developed on a slowly epirogenetic doming area, with the formation of kaolinic and arenaceous soils. During the Miocene the uplift became stronger with consequent deposition of the correlative Serra do Martins Formation and basaltic volcanism. During the more quiet Pliocene a lateritic soil developed on these sediments (Cuité Soil). The early Quaternary glaciations again caused rupture of the equilibrium, resulting in the removal of most of the sedimentary cover of the region, depositing the detritus along the coast. Erosion halted on the reappearing Jurassic planation surface elaborated in crystalline basement rocks (Sertaneja and Tabuleiros Surface). During the interglacial periods soil formation took place on the correlative deposits (Guararapes Formation, Riacho Morno Soil). The last two glaciations which apparently were of stronger intensity, caused the formation of pediments with bornhardts, and river and coastel terraces (polyphase Paraguaçu Cycle). Correlative deposits were laid down in grabens caused by tectonic reactivation (Macaiba Formation). The covering Potengi Soil was formed during the last interglacials. Recent deposition of white sands suggests a new rupture of climatic equiliblium. Paleontological evidence of this history is scarce.
Estimation of the tectonic strain ratio from the mean shape of deformed elliptical markers1977Lisle, R.J.56(2)By considering computer models representing suites of passive elliptical markers subjected to homogeneous deformation, the relationship between the strain ellipse shape (Rs = 1+e1/1+e2) and mean final axial-ratio of the markers is investigated. Random and uniform models in terms of the choice of pre-tectonic initial axial-ratios (Ri) and marker-orientation are considered. The arithmetic mean (R), geometric mean (G) and harmonic mean (H) of the final axial-ratios (Rf = long/short axis) are calculated and it is found that R departs the most from Rs. The closest of the means to the value of Rs is given by H. Using H as an estimate of Rs always gives rise to an error when the markers had a non-circular original shape. However this error diminishes relatively with increase in Rs and decrease in Ri. For the initial clast shapes present in coarse-grained detrital sedimentary rocks and Rs equal or greater than 2.5, H allows an estimation of Rs within 10% error.
A structural study in the Belgian Ardennes with sections constructed using computer based methods1977Langenberg, C.W.; Rondeel, H.E.; Charlesworth, H.A.K.56(2)A 50 km2 area in the eastern part of the Hercynian Dinant synclinorium of the Belgian Ardennes containing sandstones, carbonates and shales is macroscopically folded and cut by several faults. Using numerical procedures the area was divided into five domains within which the folding is statistically cylindrical. The domains were examined with the aid of structural cross-sections. Each section was .constructed using a computer-plot showing the positions of outcrops projected parallel to the fold-axis onto the plane of section, together with the traces of bedding. A composite plot was obtained for all five domains by first rotating four domains separately so that their fold-axes became parallel to the fold-axis in the fifth domain. Such rotations, which affect the coordinates of outcrops as well as the direction cosines of bedding-poles, can be accomplished by matrix multiplication. Sections constructed in this way, particularly the composite section, display the structure to considerable depths. The competent rock-units within the map area have been deformed into rounded parallel folds. The intervening incompetent units appear to be zones of disharmony especially in the south. Several southdipping listric thrust-faults can be discerned in the sections.
Isotopic ages in the high-grade metamorphic Coeroeni group, Southwestern Suriname1977Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Kroonenberg, S.B.; Verdurmen, E.A.T.; Verschure, R.H.56(2)Six whole-rock samples from the high-grade metamorphic Coeroeni Group in southwestern Suriname define a Rb-Sr isochron age of 2042 ± 97 Ma with initial 87Sr/86Sr = 0.7027 ± 0.0039 (λ87 Rb = 1.39 x 10-11 a-1; errors at 95% confidence level).This isochron relationship dates the event of high-grade metamorphism during the Trans-Amazonian Orogenic Cycle. The initial 87Sr/86Sr value does not record a substantial pre-metamorphic crustal history. K-Ar and Rb-Sr analyses of separated minerals (4 hornblendes, 2 muscovites and 6 biotites) yield a highly discordant age pattern, ranging from about 2000 to 1200 Ma (omitting one hornblende containing excess radiogenic argon). This pattern is interpreted as reflecting various degrees of resetting of Trans-Amazonian ages due to a low-grade metamorphic event 1200 ± 100 Ma ago (the Nickerie Metamorphic Episode). The order of mineral dates fits into the common order of radiogenic nuclide retentivities, corresponding to a temperature of about 350°C during the low-grade metamorphism.
Engineering geology - past, present and future1977Price, D.G.56(2)Engineering geology forms the bridge between geology and engineering. It is taught and practised throughout the world and fulfills all the criteria that serve to identify a separate discipline. Its strength lies in the wide range of earth sciences it encompasses while remaining firmly rooted in geology, but its diversity of interest gives rise to uncertainty over its purpose and limitations. The author briefly traces the development of the subject, attempts to define its present state relative to purpose, scope, training and practice and speculates as to further developments.
Boring sponges (Clionidae) and their trace fossils from the coast near Rovinj (Yugoslavia)1977Groot, R.A. de56(2)Boring sponges of the genus Cliona were sampled by SCUBA-diving in the Adriatic Sea near Rovinj, Yugoslavia. Boulders of limestone and shells of molluscs, infested by clionids were collected. The sponges were identified and polyester casts were made of their bore-holes. A description is presented of the spiculae of the sponges as well as their bore-holes. It appears that sponges with different spiculae excavate different borings. The borings in limestone are larger than those in shells.
Morphodynamic development and preservation of physical sedimentary structures in two prograding recent ridge and runnel beaches along the Dutch coast1977Berg, J.H. van den56(3)The two studied beaches both form part of the coastal barrier system which extends along the eastern margin of the southern North Sea. One of them (at Schouwen) is bordered by the coalescing ebb deltas of two major tidal inlets; the other one (at Zandvoort) lies beyond the in influence of inlets. The ridge and runnel beach environment is divided into areas lying relatively sheltered from wave action behind ridge or berm crests and seaward dipping surfaces exposed to the influence of swash and backwash during the tidal cycle. Both of the areas are characterized by a set of sedimentary bedforms and structures, which produce distinctive associations in preserved sediments. Comparison of data on sampled structures from buried sediment layers with information from repeated measurement of beach variation, permitted reconstruction of the location of these associations as preserved during the last few years in sections perpendicular to the coastline. Major differences in the morphodynamics of the two beaches as well as in the location of associated sedimentary structures preserved in these sections, are related to the degree to which the beaches are sheltered from storm waves and to rates of progradation.
Mud in the Dutch Delta Area1977Terwindt, J.H.J.56(3)Mud is transported to the Dutch delta area from the Rhine, Waal, Maas and Scheldt rivers (resp. 0,6; 2,5; 0,7 and 0,7 million tons/year). Above, in the Rotterdam Waterway about 3,5 million tons of mud per year are brought in from the sea. The mud of the underwater delta comes from the Channel, the Haringvliet, from biological formation, from erosion of older clay and mud deposits and from mud that is dumped in this area from the Rotterdam harbours. In recent years the last mentioned quantities amount to approximately 4 million tons per year. The mud content in the water varies greatly over the area, as illustrated in figure 2.
The effect of gas bubble formation on the physical and engineering properties of recently deposited fine-grained sediments1977Faas, R.W.; Wartel, S.56(3)Sediments in the anoxic reaches of the Veerse Meer, a tideless basin in the southwest Netherlands, possess certain physical properties which are directly dependent upon the geochemical environment in which they are accumulating. High values of water content and correspondingly low values of bulk density (unit weight) and shear strength were observed in sediments deposited in low oxygen to anoxic waters (-12 m to -20 m depth). Plasticity increased regularly with depth with highest plasticity found in the most highly reduced sediments at -20 m. One-dimensional consolidation analyses showed rapid consolidation and almost complete lack of rebound. Stress-strain diagrams show little or no reloading curves and are typical of underconsolidated or remolded sediments in which interparticle bonding is minimal. Gas generation and bubble ebullition with swelling is believed to retard normal gravitational consolidation and inhibit fabric development through continual agitation and physical manipulation of sediment particles. Both conditions (i.e., underconsolidation and remolding) exist as a direct result of methanogenesis.
Composition, transport and origin of sediments in the Schelde estuary1977Wartel, S.56(3)The grain-size characteristics (grain-size distribution, comparison of one percent value (C) of a given grain-size distribution with the median value (M) in so-called CM-patterns, silt/clay ratio's) of the Schelde estuary are distributed in relation to the existence of a turbidity maximum. Fine sand, silt and clay are deposited, while fluid mud occurs. Towards the North Sea, as well as in an upstream direction, the sediments become much coarser. Silt, clay and part of the sand are derived from the river drainage basin. Sands are also brought into the estuary from the North Sea. Flocculation is important as a depositional agent. However, deflocculation in a seawards direction, favouring seawards transport of silt and clay particles, is assumed. Movement of fluid mud deposits in relation to river discharge has not been observed. This can be explained by narrowing of the channel and the corresponding increase in stream power, where the river crosses the Boom clay (Oligiocene).
Vegetational and climatic developments during the Late Glacial and the Early Holocene and aeolian sedimentation as recorded in the Uteringsveen (Drente, The Netherlands)1977Cleveringa, P.; Gans, W. de; Kolstrup, E.; Paris, F.P.56(3)A lithological and palynological investigation has been made of the Late Glacial and early Holocene filling of a pingo remnant in Drente (The Netherlands). It was found that the deposition of aeolian sands, although of varying nature, was uninterupted from the beginning of the Late Glacial until the end of the Boreal. From the pollen records a vegetational development was reconstructed and its dependance on temperatures, moisture conditions, and soil development is discussed. It was concluded that the mean July temperatures were at least 10° C - possibly 13° C - in the Bølling, probably 12° - 13° C in the Earlier Dryas, around 14°C at the beginning of the Allerød, and at least 12° C in the Late Dryas time.
Vegetational and climatic developments during the Late Glacial and the Early Holocene and aeolian sedimentation as recorded in the Uteringsveen (Drente, The Netherlands)1977Cleveringa, P.; Gans, W. de; Kolstrup, E.; Paris, F.P.56(3)Large Enclosure 1
Vegetational and climatic developments during the Late Glacial and the Early Holocene and aeolian sedimentation as recorded in the Uteringsveen (Drente, The Netherlands)1977Cleveringa, P.; Gans, W. de; Kolstrup, E.; Paris, F.P.56(3)Large Enclosure 2
Basement tectonics from LANDSAT imagery in mining exploration1977Ramos, V.A.56(3)The mineral potentials of basement cratonic areas are evaluated on the basis of mechanical analyses of their tectonic framework, obtained from LANDSAT imagery, Tensional release targets are selected through the application of different deformational models and the identification of the stage and type of deformation. Correlation between tensional release zones and epigenetic hypogenic mineralization in different cratonic areas of South America has been successful in several mining exploration programmes.
The influence of pore water on the compaction behaviour of carbonate sand1977Boer, R.B. de; Lagrand, J.56(3)Maastrichtian Carbonate Sand collected from the Pietersberg near Maastricht (Netherlands) was compressed at room temperature, in order to detect pressure-solution phenomena. Compaction took place at slowly rising loads (10 atm/day) as well as under constant loading. The maximum loads to which the different samples were subjected varied from 15 to 280 atmospheres. The influence of the following factors on the compaction behaviour of the sand was studied: 1. presence or absence of pore water; 2. partial CO2-pressure of pore water; 3. inhibition of calcite precipitation; 4. saturation of pore water with respect to calcite; 5. circulation of pore water. At room temperature applied microscopically detectable pressure-solution phenomena were not produced. The influence of the presence of pore water on compaction was clearly demonstrated, but the pore-water composition appeared not to be a dominant factor.
A fast procedure for sampling sedimentary structures down to 1,1m in unconsolidated wet sands1977Berg, J.H. van den56(3)An inexpensive, simple and efficient method has been developed for sampling sedimentary structures, down to 1.1 m. below the sediment surface, in unconsolidated wet sands. The method can be used on land and in quiet water to a depth of at least 4 metres. The procedure makes possible the study of sedimentary structures in the form of lacquer peels measuring 1.1 m. high and 0.1 m. wide within one hour after coring has been started.
The undation theory1977Bemmelen, R.W. van56(3)
Preface - Fault tectonics in N.W. Europe1977Frost, R.T.C.; Dikkers, A.J.56(4)
Sketch of a possible lineament pattern in Northwest Europe1977Dikkers, A.J.56(4)Regional linear fracture zones, or "lineaments", are known to be elements of fundamental importance in the structure of the Variscan (Hercynian) and older basement in NW Europe. Several lineaments have shown periodic tectonic activity until very recent times; movements in different directions at different times are common. Based on data from various sources - especially aeromagnetics and Landsat images the existence of several lineaments in the North Sea area is postulated. The known and the postulated lineaments can be loosely grouped into three recognisable, but not sharply defined, directional sets: around NW-SE, NE-SW, N-S. The effect of the lineaments on the structure of the Permian and younger cover is well expressed in the segmentation of the Mesozoic-Tertiary graben systems, in particular the Central Graben-Viking Graben.
Sketch of a possible lineament pattern in Northwest Europe1977Dikkers, A.J.56(4)Large Enclosure
Fault and lineament patterns in the southern highlands of Scotland1977Johnson, M.R.W.; Frost, R.T.C.56(4)This paper discusses the mapped faults and photolineaments (observed on Landsat images) in part of the Scottish Caledonides. The prominent NNE-SSW to NE-SW trending wrench faults, including the Great Glen Fault, were active in the Upper Palaeozoic. In addition, recent studies have suggested Mesozoic/Tertiary activity along the Great Glen Fault. The Highland Boundary Fault, which forms the southeastern margin of the metamorphic Caledonides was an active reverse fault in Devonian times, and later transcurrent movements along it have been postulated. Another conspicuous fault set trends NW-SE; some of these faults were active in Mesozoic/Tertiary times. A minority of the faults trend roughly N-S or E-W. A map of lineaments from Landsat images has been constructed. The lineament pattern is shown to correspond closely to the fault pattern. Although by no means all mapped faults were observed on the satellite imagery, it is considered that some previously undescribed fractures and extensions to known faults were detected.
Fault and lineament patterns in the southern highlands of Scotland1977Johnson, M.R.W.; Frost, R.T.C.56(4)Large Enclosure 1
Fault and lineament patterns in the southern highlands of Scotland1977Johnson, M.R.W.; Frost, R.T.C.56(4)Large Enclosure 2
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Linear features (believed to represent fractures of some kind) seen on Landsat satellite images, topographic maps and geological maps have been mapped for the area of southern Norway (roughly the region south of the 65° parallel). Special attention is given to the area of the Oslo Graben. The results of the analysis are related to the main geological and geophysical features of the region, of which a brief description is given. A system of NW-SE and NE-SW sets of lineaments is present over most of the region and predominates in the Precambrian area; it is thought to be the oldest structural element. In the Caledonian belt the NE-SW set is predominant, in accordance with the general strike. A roughly N-S trending set is obviously associated with the Oslo Graben but extends well to the north of the latter; a similar pattern is also present near the west coast. An E-W set is locally associated with Devonian movements. The coastlines of southern Norway conform closely to the directions of the dominant fracture pattern in the vicinity.
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 1
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 2
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 3
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 4
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 5
Analysis of fracture patterns in southern Norway1977Ramberg, I.B.; Gabrielsen, R.H.; Larsen, B.T.; Solli, A.56(4)Large Enclosure 6
Mesozoic faulting in East Greenland1977Surlyk, F.56(4)Mesozoic faulting in the East Greenland Basin is interpreted as the result of graben formation extending from a postulated "trilete junction" south of Scoresby Sund. Faults appear slightly curved in plan, but can be divided into straight sections 2 - 10 km long (up to 20° between adjacent segments). They are normal types only, dipping 60° - 80°, with throws up to 4 km partly resulting from block rotation. Although this rotation implies faults curved in section, they can usually be assumed flat with such large radii of curvature. Major faults are often complex zones (0.5 - 4 km wide) of narrow blocks and slivers. Faulting was partly synsedimentary. Comparisons of pre-Mesozoic and Mesozoic fault directions show fairly similar dominant trends (335°, 355°, 015° - 025°,035° - 050° & 085° - 090°) in all areas, indicating that pre-existing basement anisotropies controlled directions of Mesozoic-Cenozoic faulting. Basin formation was accomplished by roughly N-S boundary faults in east and west and major NW-SE faults, which together defined a series of fault blocks (subsiding successively from south to north). In Volgian- Valanginian times, the basin was further split into N-S trending antithetic blocks by faults 10 - 30 km apart (crustal extension about 6%).
Mesozoic faulting in East Greenland1977Surlyk, F.56(4)Large Enclosure
Ancient and recent rifting in the Rhinegraben1977Illies, J.H.56(4)The Rhinegraben is part of a western European rift system. Although of different ages and trend, these rifts are situated on pre-existing basement weakness zones. Signs of Rhinegraben subsidence occur in mid-Jurassic, but true rifting began in mid-Eocene. Boundary faults are complex systems of normal faults, dipping about 65°, perhaps flattening with depth. "Horizontal stylolite" orientations indicate an Eocene palaeostress field (related to Alpine plate collision) with its minimum component normal to the graben, i.e. ideal for rifting on the basement weakness zone. Rifting continued until Lower Miocene, but the depocentre shifted north with continued development of a mantle bulge in the south. Then, although crustal upwarping and volcanism continued, graben formation ceased - the stress field was no longer appropriately oriented. Graben activity restarted in Upper Pliocene and continues today. In-situ stress measurements indicate a sinistral shear component parallel to the graben, producing different tectonic reactions in the three slightly differently oriented graben segments. This shear motion is ascribed to continuing Alpine uplift and extension pushing northwestward the block east of the graben. The Rhinegraben and Lower Rhine Embayment are connected by a continuous seismotectonic belt where rifting is controlled by pre-existent basement fractures and regional stress,
Tectonic patterns in the Danish region (as deduced from a comparative analysis of magnetic, landsat, bathymetric and gravity lineaments1977Frost, R.T.C.56(4)Lineament maps of the Danish region have been produced from three different data sources: magnetic anomaly maps, surface data (Landsat satellite images and bathymetric maps) and Bouguer gravity maps. The directional patterns produced, represented by rose diagrams, show several prominent and statistically significant directions. Three directions (WNW-ESE to NW-SE, NNE-SSW and NE-SW to ENE-WSW) are well defined by all three data sources, and are parallel to the principal structural trends in older exposed rocks framing the region studied; however, the other less prominent directions may also be of import. The close correspondence between patterns produced by surface data and by magnetic data (presumably mainly representative of the basement) is regarded as strong evidence that these patterns are tectonically significant and are probably present throughout the sedimentary cover. Systematic pattern differences are observed between three sub-areas of the region; these may reflect variations in the basement, different tectonic histories and/or different thicknesses of sediment.
An experimental approach to basement-controlled faulting1977Horsfield, W.T.56(4)To assist in the interpretation of fault structures in the North Sea, a programme of scaled-model experiments was run in a specially-built sandbox. Faults were produced in the sand overburden in response to normal displacement along faults in the underlying basement. Variations in overburden fault geometry were studied in relation to the attitude of basement faults and variations in sand properties. A stereoscopic method was used to analyse successive stages of development. In the experiments, two stages were observed. Initially, curved precursor faults formed, particularly over high-angle basement faults. These were followed by planar normal faults. Over low-angle basement faults, antithetic as well as synthetic normal faults were prominent.
Early subsurface temperature measurements in the Netherlands1978Visser, W.A.57(1)The earliest known subsurface temperatures were obtained in 1879 in a borehole (to in the a depth of 365 m) centre of the city of Utrecht. During the years 1912 - 1914 temperatures were measured to depths as great as 1400 m in a number of wells in structurally high areas in Tertiary, Senonian, Triassic, Upper Permian and Carboniferous rocks. In 1952 additional data were obtained (Peel horst), followed in 1956 by a few measurements in the South Limburg mining district. The various thermometers used are briefly described. The temperatures are related to lithology and stratigraphy and to the salinities of the interstitial waters. very low geothermal gradients are present in Quaternary to uppermost Tertiary due to percolating waters of meteoric origin. In the post-carboniferous overburden and, where shallow, in the higher parts of the Westphalian the waters are either fresh, or, if saline, do not reach sea-water concentrations. In such areas the geothermal gradients are lower than 3°C/100 m. In the Carboniferous, due to the low thermal conductivity of coal, gradients tend to be high: over 4, and reaching 5.2 to 5.6°C/100 m. In contrast, the high conductivities of anhydrite and rock salt cause low gradients (2.5 in the Buntsandstein and Zechstein formations).
Geological thinking and mapping in the Netherlands before and during Staring's lifetime1978Thiadens, A.A.57(1)This paper deals with geological thinking and mapping in The Netherlands before and during the life of W.C.H. Staring (1808-1877). During the last two centuries there have been two centres of geological activity, viz. Groningen and Haarlem. Some outstanding pre-staring geological achievements are mentioned. As typical items, which may give an idea of the geological thinking in The Netherlands in the past, special attention is paid to theories about the origin of peat, the provenance of erratic boulders, and the mapping of Quaternary The first geological map of the Netherlands (scale 1:200,000) was made by Staring, who is considered the father of Netherlands geology.
Phylogenetic sequences of Lower Cretaceous benthic foraminifera and their use in biostratipgraphy1978Bartenstein, H.57(1)Ten stratigraphically important phylogenetic sequences of benthic index foraminifera in the Lower Cretaceous are described. Their distribution is examined in North West Germany, which belongs to the north temperate facies realm, and they are also found to be, in part, of stratigraphic importance in the Lower Cretaceous throughout the world, including the tethyan facies realm. The development and importance of such phylogenetic sequences for biostratigraphic determinations is emphasized; the paper concludes with a supplementary note about the validity of statistical analyses as applied to phylogenetic Iineages.
New data on Early Dinantian (Early Carboniferous) stratigraphy and sedimentation in South Cork, Ireland1978Gelder, A. van; Clayton, G.57(1)The sedimentology and stratigraphy of the Dinantian (Lower Carboniferous) Kinsale Formation are described from ten major coastal sections in south Cork, Republic of Ireland. Palynological correlations between the sections are outlined, and subdivision of the Kinsale Formation into three members is proposed. Members I and 3 are dominated by mudrocks, and are separated by the more sandy member 2. Sediments assigned to member 1 were deposited in a deep-water, marine environment below wave base, whereas members 2 and 3 were deposited on a shallow marine, muddy platform, where sandy shoals built up. The latter are especially well developed in member 2.
The palaeoenvironment of the Kempenland clay deposits (Lower Quaternary, N. Belgium)1978Geys, J.F.57(1)Grain-size analyses show that the Kempenland deposits (Lower Quaternary, N. Belgium) were deposited in an environment of rather quiet water with a low flow energy and no tidal influence. Electron microscopical investigations indicate that the water contained few salts. The sedimentary structures are the result of an unidirectional current towards the northwest, in a river with a mainly meandering character. No evidence could be found for a marine, littoral or perimarine genesis. Most probably the Kempenland deposits can be placed within the Kedichem and Tegelen Formations of Dutch authors.
Sand and gravel from shallow seas1978Oele, E.57(1)Various factors which influence the economic feasibility of offshore mining are discussed. The mined sands and gravels are used for constructional purposes. Therefore, some specifications of the grainsize distribution of the exploitable product are mentioned. A gravel exploration by the Netherlands Geological Survey in an area off the Norfolk coast is mentioned. Some special samplers, used for this purpose, are described. Sand and gravel on the shelves have been transported and supplied by rivers, glaciers, wind and locally by longshore currents. Marine erosion may contribute as well. The North Sea and English Channel are good examples of an aggregate-bearing shelf, since shells, sands and gravels are all present. The availability is at least as important as the transporting agents. Controlling include a.o. climate, tectonic instability and distance from the source area. Even in the Pleistocene the weathering processes in the tropical zones resulted in only small amounts of sand and gravel reaching the present-day shelf areas. In the subtropical zone the humidity and tectonic instability are a prerequisite for their presence) whereas in the temperate zones various mechanisms have led to mineable deposits. From a combination of prospective areas and densely populated regions it follows that only very restricted parts of the shelf are of interest as far as mining is concerned.
Theoretical stress conditions in the matrix around a rigid circular inclusion and their geological implications1978Hossain, K.M.57(1)Equations are derived which describe the stress condition in the matrix around a rigid circular inclusion subjected to uniaxial stress. The values of the principal stresses and their orientations are obtained using a computer. The orientation of potential fractures around an inclusion is determined from the stress trajectories and the development of pressure shadows and pressure fringes are predicted by assuming that mineral migration occurs in response to gradients in the mean stress. The type of structures (whether pressure shadows or pressure fringes) that develop in the low mean stress zone adjacent to the inclusions is controlled by the magnitude of applied stress.
Contrasts across the shear zone in the Precambrian rocks of Western Singhbhum1978Bhattacharyya, D.S.57(1)A prominent shear zone runs E-W across Singhbhum. Structural analysis indicates three phases of folding, all with E-W axial planes dipping northerly or subvertically to the north of the shear zone. South of this shear zone there are two phases of folding consisting of earlier folds with NNE striking axial planes, overprinted by later E-W folds. This marked structural contrast, along with other contrasting characteristics, indicates a large horizontal displacement that juxtaposed the two separate orogenic belts. Kinematic patterns indicate that such a large horizontal displacement could have been brought about by a sinistral transcurrent shear during the second phase of deformation seen in the north. The changes in kinematic patterns from N-S compression to transcurrent movement to N-S compression again during the same Singhbhum orogeny are of great interest.
Diagenetic and metamorphic evolution of Cambro-Ordovician siliclastic sediments in Northwestern Spain1978Gietelink, G.57(1)The diagenetic and metamorphic evolutions of the Cambro-Ordovician silicictastic sediments of the Luna area, which formed part of the Lower Palaeozoic stable shelf, and of the Sil area, which was situated in the adjacent geosyncline, were determined and compared. The overburden in the Luna area reached 2500-3500 m, based on stratigraphic evidence. This is in agreement with the mineral association occurring in the sediments (authigenic illite with minor amounts of detrital kaolinite and authigenic muscovite and chlorite), indicating a depth of burial of 2000-3000 m. The sediments were subject to diagenetic changes, which occurred shortly after deposition before lithification (syndiagenetic phase), in the lithified rocks (anadiagenetic phase) and after uplifting and erosion of the area (epidiagenetic phase). Based on stratigraphic evidence, the overburden of the sediments studied in the Sil area ranged from 5000 to 14000 m. The mineral associations observed in the sediments (illite-muscovite-chlorite in the upper part and muscovite-chlorite-biotite in the lower part of the succession) are not in agreement with the estimated depth of burial. The sediments of the Sil area underwent diagenetic alterations similar to those of the sediments in the Luna area, but the effects are obscured by metamorphic recrystallization, which occurred during the Hercynian orogeny. During this period the area was affected by regional metamorphism.
Structure of the Northeastern plateau of the Bahariya oasis, Western desert, Egypt1978Elbassyony, A.A.57(1)The structural studies of the northeastern plateau concern two fold axes trending NE-SW. The first fold axis runs through the ElHarra and ElGedida areas. The second fold axis runs through the Gebel Ghorabi and Dumbell's Hill areas. Between these two fold axes lies the plunge of the northeast anticline (Ghorabi anticline) of the Bahariya high. Two periods of deformation have affected the investigated area. The first one is considered to be a part of the Syrian arc system (of the Laramide cycle) that extends in post-cenomanian - pre-Campanian time from Bahariya to Abu Rawash near Cairo. The second one is considered to be a part of the Alpine cycle. It affects the Eocene and Oligocene sediments. Faulting accompanied both periods of deformation. The fault systems: NE-SW (aualitic), E-W (Tethyan) and NW-SE (African) are recognized.
Tentative explanation of the late glacial and Early Holocene climatic changes in North-Western Europe1978Geel, B. van; Kolstrup, E.57(1)
A recently discovered nickeliferous serpentinite from Uda Walawe, Sri Lanka1978Dissanayake, C.B.; Riel, B.J. van57(1)
1978Gillavry, H.J.M.; Beets, D.J.57(2)
Polyphasic Tertiary Tectonics of the interior range in the Central Part of the Western Caribbean chain, Guarico state, Northern Venezuela. 1978Beck, C.M.57(2)The southern -non metamorphic- belt of the Western Caribbean Chain is composed of the superposition of several tectonic units with an upper Cretaceous-Palaeocene content. The whole –called 'Piemontine Nappe'- was detached from an Albian and pre-Albian substratum and suffered two major compressive tectonic phases with southward displacements. The first phase Lower Middle Eocene- produced the allochthony of the previously tectonized Villa de Cura Nappe, which was strongly shortened. During the Oligocene (?) -Miocene period, a wide subsiding furrow appeared along the southern margin of the palaeorelief formed before in relation with a NNW-SSE distension. The second tangential phase -Middle-Upper Miocene- produced a partial overthrusting of the Piemontine Nappe on the Miocene terrains and a new shortening of the latter. An earlier phase may have affected the northern part of the Piemontine dominion in the lower Senonian. This hypothesis and the preceding conclusions are in opposition with the theory -generally held- of a displacement of the Villa de Cura Nappe as due to a continuous sliding occurring during Maastrichtian and Palaeocene time and followed by a continuous sliding of the Piemontine Nappe from Upper Eocene to Miocene time. The hypothesis of tectonisation by gravity sliding is discussed and discarded.
Seismic investigations in the Colombia, Venezuela and Grenada Basins, and on the Barbados ridge for future IPOD drilling1978Biju-Duval, B.; Mascle, A.; Montadert, L.; Wanneson, J.57(2)The geological setting of five sites for future IPOD drilling in the Caribbean is described. These sites were surveyed in 1976 by IFN-CNEXO with 2800 km of multichannel seismic records. The first two sites straddle the lesser Antilles island arc where the oceanic Atlantic plate is subducted westwards under the Caribbean plate. The main objectives of these sites are to investigate the frontal overthrust of the Barbados Ridge (accretionary prism) on the Barracuda abyssal plain, and the age and nature of sediments and crust of the back a¡c basin, e.g. the Grenada Basin. The three other sites are located in the Venezuela and Colombia Basins in order to understand their composite structure better and to compare their geological history with the geological evolution of their surrounding margins.
Anomalous crust in the Eastern Venezuela Basin and the Bouguer gravity anomaly field of northern Venezuela and the Caribbean borderland.1978Bonini, W.E.57(2)A new Bouguer gravity anomaly map is presented for the southern Caribbean borderland and northern South America. Major features are; the Lake Maracaibo-Venezuela Andes minimum (-160 mgal); gravity maxima in the Venezuelan offshore area and on the Netherland Antilles; a steep gradient (- 4.7 mgal/km) south across the Western Caribbean Mountains; the termination on Margarita ultra-mafic rocks of the minimum trend of the Lesser Antilles; and the broad gravity minimum (-200 mgal) to the east and anomalous maxima (+10 mgal) to the west associated with the Eastern Venezuela Basin. Gravity models have been calculated for two sections over this basin. The broad gravity minimum in the east can be explained by up to 15 km of sediment and crustal downwarping to a depth of 47 km. The maxima suggest an anomalous crust, possibly caused by a higher-density basement, a crustal upwarp, or both. The trend of the gravity maxima parallels those of the Eastern Venezuela Basin minimum and the Antillean trends as they enter Venezuela. In addition they are parallel to the ENE structural trends of the Precambrian south of the Orinoco River. Thus, the anomalous sub-sediment rocks could be related to Mesozoic tectonics, or Precambrian basement features.
Paleogeografía del Paleógeno de Cuba oriental1978Brezsnyanszky, K.; Iturralde-Vinent, M.A.57(2)The changes in the tectono-sedimentary regimen between the volcanic arc stage and the platformlike stage in eastern Cuba are studied. During the Palaeocene and Lower Eocene volcano-sedimentary deposits predominated in the territory, derived from volcanic centres in the present Sierra Maestra. Transgressive carbonate sedimentation in the Middle Eocene succeeded the extinction of the volcanic activity. In the Upper Eocene a new tectono-sedimentary regimen started. Terrigenous and carbonate-terrigenous deposits played the fundamental role, and a regression started, which continued into the Middle Oligocene. At that time two islands, separated by a mediterranean channel, developed between the Golfo de Guacanayabo and the Bahía de Nipe. During the Upper Oligocene a new marine transgression started, which reached its maximum development in the Lower Miocene. The change from a volcanic arc regimen to the platform-like stage was marked by a great relief inversion. The Nipe-Guacanayabo fault need not have been a sinistral transcurrent fault; if it is, then it did not have a great displacement in the Palaeogene. The territory of eastern Cuba during the Palaeogene can be divided into a northern more stable part, and a southern unstable part. The characteristics are related to a progressive continentalization from Cretaceous to Palaeogene, and from north to south.
The dispersion of Na, K, Ca and Mg along the footwall of a Pb-Zn ore body, Hope Mine, Jamaica.1978Carby, B.E.57(2)The Hope Mine lead-zinc deposit is located near the western margin of the Wagwater Belt, Jamaica. The galena-sphalerite mineralisation is associated with an andesite body of (?) Eocene age and was deposited from hydrothermal emanations. The dispersion patterns of Na, K, Ca and Mg in two adits of the mine are briefly described and the results are presented. The ratios MgO/CaO and K2O/Na2O are calculated. It is found that this ratio might be useful in locating ore bodies of this type.
Aspects of the attitude of mafic sheets in the Western Cordillera of Colombia1978Boorder, H. de57(2)Changes in the attitude of sheet-like bodies of mafic rocks ('diabase') are discussed in relation to changes in the attitude of the bedding of intercalated and otherwise associated sedimentary rocks. Examples are presented in photographs of outcrops along the main road between Buga and Buenaventura, W. Colombia. The mafic sheets of the Colombian Western Cordillera and their mode of emplacement are compared with the sheets of the Sheeted Intrusive Complex of Cyprus, with reference to the sheet swarms of Iceland. Horizontal emplacement of sheets, never questioned in the Western Cordillera of Colombia, is considered as an alternative to vertical emplacement of sheets, previously suggested for the Sheeted Intrusive Complex of Cyprus. The subject matter is thought to be of importance in the (geophysical) study of the framework of the ocean floors. Further field investigation of the volcanic-sedimentary complex of the Western Cordillera of Colombia should be encouraged.
New data on rudist assemblages in Cuba1978Torre, A. de la; Jakus, P.; Albear, J.F. de57(2)A review of the most important publications about the rudist assemblages in Cuba is offered. A faunal assemblage from the eastern part, belonging to the Maastrichtian (Titanosarcolites fauna), is studied. It includes both Titanosarcolites and Barrettia. Four faunal assemblages are recognized in the Cuban Upper Cretaceous: (1) Tepeyacia fauna, probably Cenomanian-Turonian age; (2) Durania fauna, probably of a Santonian or Coniacian age; (3) Barrettia fauna; and (4) Títanosarcolites fatna. The last two are of a (probably Upper) Maastrichtian age and are corresponding to either two different stratigraphic horizons or two different facies in that age. The relationship between these two assemblages must, however, still be investigated, although the Barrettia fauna probably is somewhat older than the Titanosarcolítes fauna, according to the work of Chubb (1956, 1961). Some evidence about the occasional association of Titanosarcolites and Barrettia at some Cuban and West Indian localities is mentioned.
The distribution of igneous rock suites throughout the Caribbean1978Donnelly, T.W.; Rogers, J.J.W.57(2)New analytical determinations for more than one hundred igneous samples enable us to place several circum-Caribbean igneous series into a tentative tectonic perspective. We consider that the basaltic rocks from Curaçao, Aruba, Tiara (Venezuela), and the mafic intrusives of the Paraguaná Peninsula (Venezuela) belong to a MORB association of possible early Late Cretaceous age, which is correlative with basinal basalts from the Caribbean, and which has been tectonically emplaced after eruption on to the continental border. Some stratigraphically early volcanic complexes from Jamaica, Dominican Republic, Désirade, Tobago, and Bonaire are placed in the primitive group, along with the early volcanics of Puerto Rico and the Virgin Islands. Plutonic rocks from Haiti and the Pedro Bank are somewhat high in K but not broadly different from those of Puerto Rico. The young volcanics of the central Dominican Republic are of the shoshonite (high-K) group. The plutonics of the southern Caribbean continental borderland are probably all calcalkaline, including those of Tobago. Several are notably high in cobalt, which further demonstrates that the southern Aves Ridge plutonics belong here and are not part of some other series.
Marine lithification of reef rock and rhodolites at a fore-reef slope locality (-50m) off Bermuda1978Focke, J.W.; Gebelein, C.D.57(2)At a depth of 50 meters the fore-reef slope at the northern margin of the Bermuda platform consists of solid reef rock interspersed with sand patches and channels. Coralline algae are the predominant framebuilders, the only common coral being Montastrea cavernosa. On the rippled sand abundant red algal nodules (rhodolites) occur with diameters up to 12 cm. Both reef and rhodolites show various stages of alteration and lithification by repetitive boring, secondary framebuilding, internal sedimentation and cementation. All processes are marine. Aragonite cement occurs only within the in situ deposited primary framework, and is probably a very early, post mortem precipitate. Magnesian calcite is the only common cement on all other substrates. Practically all porosity and permeability is destroyed within approximately 1500 years. Net accretion rates in the rhodolites are in the order of 0.05 mm/year. With local current patterns providing a suitable pumping mechanism, the very slow accretion rates are thought to be the main reason for the pervasive nature of diagenetic alteration on this fore-reef locality. Rhodolites of this type may be useful palaeo- environmental indicators for deep (more than 50 m) tropical waters.
Development of the coral facies from the Oligocene to the Recent in Eastern Cuba).1978Franco, G.L.; Nagy, E.; Radocz, G.57(2)Coral formations of eastern Cuba occur around two anticlinoria in zones progressively further from the axis and nearer to the present coast. A lagoonal facies prevails. The oldest fauna, found in the Guantánamo Basin, is of Oligo-miocene age; it correlates with faunas of Antigua and the Panama Canal Zone. The fauna is of Indopacific type and grew on a gravel bottom in quiet water (Corallinacea-Lepidocyclina community). The temperature favoured true reefal growth. An abrupt change occurred at the boundary Early/Middle Miocene, possibly because of an interoceanic influx of cooler water. The development is mostly biostromic. More favourable conditions reappear in the Upper Pliocene. Pleistocene coral zonation resembles that of the Netherlands Antilles, but is less well outlined. Fifty percent of the fossil species listed occurs in Recent reefs and lagoons.
Late Pleistocene depositional and denudational history of Aruba, bonaire and Curaçao (Netherlands Antilles)1978Herweijer, J.P.; Focke, J.W.57(2)A sequence of subaerial denudation benches, which are recognized as remnants of planation surfaces, has been found in the drainage basins of Aruba, Bonaire and Curaçao. The benches were formed during periods of relatively stable sea-level. This denudational sequence has been correlated with the late Pleistocene marine limestones of the islands. These limestone deposits represent eustatic sea-level maxima. The correlation led to a revised stratigraphy of the marine strata. At least ten units, each representing an individual sealevel event, have been recognized. One of the units (presently + 10 m above sea-level) is correlated with the 125,000 B.P. highstand. The rate of tectonic uplift is estimated to be in the order of 0.05 m/1000 year.
Notes on the Tertiary stratigraphy of Margarita Island1978Hunter, V.F.57(2)Micropalaeontological evidence is presented for a further refinement of the Tertiary stratigraphy of Margarita Island, Venezuela. The writer supports Bermudez & Gamez (1966) and Butterlin (1970) in determining the uppermost beds of the Punta Mosquito Formation as no younger than the Truncorotaloides rohri zone of the Middle Eocene. Caudri's (1974) evidence for possible deposition of Upper Eocene sediments is challenged. Micropalaeontological studies and field observations indicate the La Guica Formation to be a middle clay member of the Mio-Pliocene Cubagua Formation. Rich planktonic foraminiferal faunas from this horizon are identified as representing the Late Miocene Neogloboquadrina dutertrei zone of Bo[i & Bermudez (1965). The Los Bagres limestone is interpreted as allochthonous blocks of Paleocene or Early Eocene age within the conglomeratic facies of the Lower Eocene Las Bermudez Formation. The time gap represented by the Miocene-Eocene unconformity on the island can be demonstrated to extend through Late Eocene to Late Miocene time.
Foraminiferal correlation of Tertiary mollusc horizons of the soutern Caribbean area1978Hunter, V.F.57(2)Correlations of conspicuous Tertiary mollusc horizons described from the southern Caribbean area are attempted on associated micropalaeontological evidence. By this method the rich mollusk horizons characteristic of the Springvale Formation of Trinidad, the Punta Gavilán Formation of Venezuela, and the Tubará Formation of Colombia are considered time-correlatable at the Early Pliocene level. The Cantaure mollusc horizon of the Paraguaná Peninsula of northern Venezuela contains an Early Miocene (Burdigalian) microfauna and is correlatable with that of the basal part of the Castilletes Formation of the Guajira Peninsula of northern Colombia and the Quiroz horizon of the La Rosa Formation of the Maracaibo Basin. The 'Raetomya Shales' of the Jarillal Formation of western Venezuela correlate with similar macrofaunas found in the Caus Formation and other transitional facies units associated with the contact of the Middle Eocene Misoa and Pauji Formations of the Maracaibo Basin, and those of the Ceru Mainsji Formation of the island of Curaçao. These horizons can be clearly calibrated with the Truncorotaloides rohri and Orbulinoides beckmanni zones of Bolli's (1966) planktonic foraminiferal zonation. There is also micropalaeontological evidence to suggest that the Hannatoma horizon of western Venezuela can be associated with the final regressive depositional phase of the Middle Eocene throughout northwestern South America.
Tectonic movements during the oscillating development of the Cuban platform1978Iturralde-Vinent, M.A.57(2)The geological development of Cuba has been of the platform type since the Late Eocene. A mosaic of blocks was formed, comprising five grabens, six horsts and four semigrabens, delimited by faults and flexures. The platform as a whole oscillated with a median period and amplitude. The blocks themselves oscillated with three superimposed waves: (1) oscillations with a period of the order of hundreds of millions of years and an amplitude of thousands of metres; (2) oscillations of a million to tens of millions of years, and amplitudes of hundreds to thousands of metres; and (3) oscillations of short periods of thousands of years and an amplitude of tens of metres. These movements are conditioned by a tensional regime and the external manifestations of processes in the subcrustal mantle.
Metasomatism in the Tertiary volcanics of the Wagwater Belt, Jamaica, W.I.1978Jackson, T.A.; Smith, T.E.57(2)The Wagwater Belt represents part of a former inter-arc basin in which approximately 5,000 m of Tertiary sediments and volcanics accumulated. The volcanics are made up of minor amounts of submarine mafic flows and their sedimentary derivatives, and extensive silicic flows, volcanic breccia, conglomerates and tuffs. The mafic flows have been identified as basalts and spilites, and the silicics as dacites and quartz keratophyres. The stable-element geochemistry of the spilites is similar to that of the basalts. Ti, Zr and Y indicate that these mafic rocks were erupted in an intra-plate tectonic setting and are comparable to plateautype tholeiitic basalts. The levels of concentration of the stable elements in the quartz keratophyres are comparable to those of the dacites. The rare-earth elements of these silicic rocks confirm that they belong to the calc-alkaline series. Mineralogical, textural and geochemical data support the view that most of the basalts and dacites in the Wagwater Belt were metasomatized to spilites and quartz keratophyres respectively.
Reproduction and life cycle of Sorites orbiculus (Forskål), Foraminifer1978Kloos, D.; Gillavry, H.J.M.57(2)A sample of megalospheric Sorites orbiculus from lagoon Awa di Oostpunt, Curaçao, contains a surprisingly large percentage of adults with brood in the reproduction chambers. Measurements of the initial chambers of a parent do not differ significantly from those of the offspring. This suggests a paratrimorphic life cycle. Two specimens contain undeveloped embryos consisting of protoconch only or of protoconch with incipient flexostyle. It is concluded that protoconch and flexostyle are separate chambers, and that brood formation proceeds with considerable but not perfect synchronism. These protoconchs have thin walls and are perfectly circular in outline; they will be somewhat deformed by the formation of the flexostyle around them after which the wall will be thickened. The question is raised whether Leutenegger's two plurinucleate specimens with micronuclei could not be diploid megalospheric schizont/gamonts in which case the haploid generation would be reduced to the micronuclei and gametes. The diploidy of such a parent can be tested if the gametes produced by it can fuse inter se into viable zygotes.
Unconformity between Cretaceous and Eocene rocks in Central-Western Puerto Rico: A concept rejected1978Krushensky, R.D.57(2)A major unconformity between rocks of Late Cretaceous and Eocene age in central-western Puerto Rico was previously reported. Recent work suggests that the evidence cited is invalid: (1) because sediments which were interpreted as a basal conglomerate appear to be a fault breccia related (in all areas but one) to gravity sliding; (2) because more extensive mapping has shown that the lithologically distinct Anón Formation, known locally to contain fossils of early Tertiary age, interfingers conformably with formations which contain fossils of Late Cretaceous age. The evidence indicates that deposition in central-western Puerto Rico has been continuous from Late Cretaceous to at least Middle Eocene.
Pseudorbitoids from the Parguera Limestone, Puerto Rico, and from the Back Rio Grande Limestone, Jamaica, with remarks on the pseudorbitoidal evolutionary pattern1978Krijnen, J.P.57(2)Pseudorbitoides curacaoensis and P. israelskyi are described from two localities near Parguera, SW Puerto Rico, and P. trechmanni trechmanni and P. ?rutteni rutteni from respectively the Back Rio Grande and Rio Grande (Blue Mountain inlier, Jamaica). The evolutionary pattern of the pseudorbitoids is discussed on the basis of the present material and of samples described previously from Curaçao and from western Jamaica.
Geology of the northern, central and south-eastern Blue Mountains, Jamaica, with a provisional compilation map of the entire inlier1978Krijnen, J.P.; Lee Chin, A.C.57(2)An interpretation of successive geological events is proposed, based on lithological and palaeontological evidence encountered in the northern, central and south-eastern Blue Mountains, Jamaica. A provisional geological map of the entire inlier is given. An interpretation of a number of structural features includes some remarks regarding a plate tectonic model of the northern Caribbean plate margin.
Seismic risk and earthquake insurance in south and Central Amerika1978Kulhánek, O.; Båth, M.57(2)A method is developed for the calculation of earthquake insurance coefficients, defined as annual premiums normalized by the value of the insured property, taking account of the extent of damage, time element and building type. The method is applied to the seismic histories of capital areas in South and Central America.
Active margin structures within the North slope of the Muertos trench1978Ladd, J.W.; Watkins, J.S.57(2)Seismic reflection records from the north slope (landward slope) of the Muertos Trench south of Hispaniola reveal features similar to those seen on reflection records from Pacific active margins. Tectonically rotated sediment ponds characterize the slope; landward-dipping reflection horizons within the wedge of sediments underlying the slope suggest possible fault planes. Oceanic crust can be traced landward of the trench axis for tens of kilometers beneath the sediment wedge. Seismic refraction velocities are similar to velocity profiles found in Pacific inner trench slopes. The above similarities between the Muertos Trench inner slope and the inner slopes of Pacific trenches suggest similarities in tectonic origins. Although the Muertos Trench, unlike Pacific trenches, is not associated with a belt of active volcanism or a well-defined Benioff zone, models that explain the structure of Pacific trench inner slopes in terms of imbricate thrusting may also apply to the north slope of the Muertos Trench
Active margin structures within the North slope of the Muertos trench1978Ladd, J.W.; Watkins, J.S.57(2)Large Enclosure
The central Falcon igneous suite, Venezuela: alkaline basaltic intrusions of oligocene-Miocene age1978Muessig, K.W.57(2)Basaltic igneous rocks crop out in a 50 km belt within Oligocene sedimentary rocks in the central Falcon Basin of northwestern Venezuela. Outcrop patterns, structural orientations, chilled margins, baked contacts, sedimentary inclusions, igneous breccias and uniformly alkaline compositions suggest these bodies are shallow intrusives and extrusives. Potassium-Argon determinations on a sill yield a 22.9 ± 0.9 Ma age which is 5 Ma younger than paleontologic ages of surrounding sedimentary rocks. A span of igneous activity from 28 to 23 Ma is inferred from stratigraphic constraints. Locally, normal NNW-SSE growth faults are present in Oligocene units. Features of similar regional trend and evidence of growth faulting offshore imply a tensional tectonic regime during Oligocene-Miocene time. The tensional regime, silica undersaturated, alkaline nature of the igneous rocks, and rapid basin subsidence rates suggest a pull-apart basin model for the Falcon Basin – Bonaire Trough area. This resulted from commencement of Caribbean - South American transform motion over a wide zone of offset transform faults.
Caribbean dresge haul compilation: Summary and implications1978Nagle, F.; Erlich, R.N.; Canovi, C.J.57(2)The locations of 400 dredge hauls from the Caribbean have been compiled from published and unpublished sources. The following information on them is listed: location, depth, rock types recovered and age, and a literature reference or institution to contact for further information. The rocks recovered provide information about the Caribbean crust along the northern border of the Caribbean from Central America to Guadeloupe; and under the Beata and Aves Ridges. They also provide evidence for extensive vertical motion (up to several thousand meters) in the Neogene throughout the northern and eastern Caribbean. Many of the dredge hauls already collected have been examined in a selective fashion only. We could significantly increase our knowledge of the Caribbean crust and Neotectonics through more systematic team investigations. There are no dredge hauls from the southern and southwestern Caribbean margins. Suggestions for five localities are made.
Retrograde cataclastic gneiss north of Motagua fault zone, East Central Guatemala1978Newcomb, W.E.57(2)An areally extensive quartz-monzonitic gneiss, characterized by a variety of cataclastic textures, has been mapped as the structurally lowest member of the Chuacus Group in east-central Guatemala. This apparent orthogneiss is separated from overlying Chuacus Group metasediments (phyllite and marble) by a south-dipping, low-angle thrust. The appearances of the gneiss is variable, ranging in texture from ultramylonite to blastomylonite gneiss. Retrograde mineral assemblages characteristic of the upper-greenschist facies (quartz-microclineoligoclase-biotite-chlorite) developed in response to cataclastic deformation adjacent to the Motagua fault zone, and do not represent regional metamorphism in the classic sense. The areal extent of the gneiss suggests that it may be a fundamental basement unit north of the Motagua fault zone in Guatemala's Cordillera Central. It has not been recognized south of the fault zone.
Hydrocarbon potentian of the Trinidad area - 19771978Persad, K.M.57(2)It is now recognized that deltaic and associated sands, together with porous marine limestones, form the vast majority of the reservoirs in the major accumulations of hydrocarbons throughout the world. The source of the hydrocarbons is now thought to be kerogen which is generated from the organic content of principally marine shales which are formed in or near the continental shelves. The Trinidad area contains several sedimentary sub-basins, most of which consist largely of deltaic and associated sediments. These sediments, like most of the ancient deltas of the world, contain major reserves of oil and gas. Other less important reserves should occur in sporadic (time-wise) porous Iimestones. The total proven and probable reserves of the Trinidad area are around 5 billion barrels of oil, of which 1.6 billion barrels have already been produced, and over 47 trillion cubic feet of gas
Morphology and sediments of the shelf around Martinique Island1978Pons, J.C.; Julius, C.; Klingebiel, A.; Pujos, M.57(2)The oceanic cruise called 'GUYANTE' was aimed at the shelf of Martinique Island. It has been possible to re-establish and to state precisely the structural dissymmetry which opposes the Caribbean slope to the Atlantic. The four large sedimentary areas developed here are also different because of structural features.
Rb-Sr evidence for episodic intrusion of the late Cretaceous tonalitic batholith of Aruba, Netherlands Antilles1978Priem, H.N.A.; Beets, D.J.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verdurmen, E.A.T.; Verschure, R.H.57(2)Rb-Sr investigations revealed an age of 85.1 ± 0.5 Ma (Coniacian-Santonian) for the northwestern part of the tonalitic batholith on Aruba, and an age of 70.4 ± 2.0 Ma (Maastrichtian) for the remaining part. The dates are interpreted in terms of an episodic intrusion of the batholith. It is discussed that the two episodes of tonalitic magmatism belong to two different tectonic-magmatic phases in the geologic evolution of the Caribbean region.
Possible use of tropical peats as fuel: an example from Jamaica1978Robinson, E.57(2)Preliminary examinations of two Holocene coastal peat deposits in Jamaica have indicated more than 150 million wet tons of peat, exceeding 10 m depth in places. Most of the peat is of the sedge marsh type, bordered on the seaward side by mangrove peats. It overlies clays, resting in turn on faulted Tertiary limestone blocks. Although ash contents are comparatively high (usually more than 10%, dry weight basis), peats of this type could be attractive as sources of energy in developing countries, such as Jamaica, which have no indigenous supplies of fossil fuel. Deposits similar to those in Jamaica are probably widespread, but few studies appear to have been carried out on peats for fuel in tropical areas.
Relationship between plate tectonics and geothermal heat flows in Sucre Central, Venezuela1978Rodriguez, S.E.57(2)The geothermic zone of Sucre Central, which extends from Cariaco to El Pilar, lies in a strongly tectonized area, in which the El Pilar fault is an important feature. These faults of supracontinental character form one of the southern boundaries of the Caribbean Plate. As a result of this tectonic setting, the northern part of the country (and specially Sucre Central) shows much evidence of geothermal activity, abnormal heat flows, constant seismic activity, and a continuous rejuvenation of the local structures. The presence in Sucre Central of Tertiary dacites, which affect strongly tectonized metamorphic sequences, and which are situated in a zone with enrichment of Pb and Zn, indicates the presence of deep-seated heat chambers which are associated with the deep plate tectonics of northern South America.
Baritization in the Villa de Cura complex, state of Aragua, northern Venezuela1978Rodriguez, S.E.57(2)Along the northern coast of Venezuela a metallogenic zone has been discovered, which is characterized by masses of barite in metamorphic volcanics and sediments of the Villa de Cura Group. This zone is situated at 25 km SE of the city of Villa de Cura, in the industrial centre of the country. The minerals occur in lenses and masses within a sequence of strongly tectonized phyllites and meta-andesites of the El Chino Formation. Most probably these deposits are associated with the numerous occurrences of metals along the Villa de Cura complex in the states of Guárico and Aragua.
Stratigraphy of the Chuacús group on the south side of the Sierra de las Minas range, Guatemala1978Roper, P.J.57(2)The Chuacús Group is a complex of metamorphic rocks in an east-west belt along the Central America Cordillera between the Chixoy-Philochic fault zone to the north and the Motagua fault zone to the south. Newcomb (1975) proposed a stratigraphy for the middle and eastern portions of the Sierra de las Minas range. This investigation attempts to extend that stratigraphy to the western end of the range. To achieve this, some of the formations proposed by Newcomb must be modified, and at least one new formation is introduced. Newcomb's San Augustín Formation is the lowest unit of the Chuacús Group and has not been recognized in the western end of the Sierra de las Minas range. In El Progreso quadrangle several major modifications are needed for the overlying Jones Formation. The mafic composition of this unit may in part be due to metasomatism during Mesozoic to Tertiary serpentinite emplacement. A hornblende gneiss occurs in the lower part of this sequence.
Geochemistry and age of the Tobago igneous rocks1978Rowley, K.C.; Roobol, J.M.57(2)The island of Tobago, situated at the SE corner of the Caribbean plate, is made up of groups of volcanic, plutonic and metamorphic rocks. Thc volcanics are mainly calc-alkaline island-arc rocks which range from basalts to rhyotlacites. They have been affected by metamorphism of the lower zeolite zone facies. The plutonic rocks, which intrude the volcanics range from high-Al gabbros to biotite granodiorites, are much fresher. The metamorphics arc of the greenschist facies and are overlain by the volcanics. All these rocks were hitherto believed to be of Cretaceous age, but new K-Ar dates from the freshest available samples, including a mineral determination, show a Lower Cretaceous age for the pluton. It therefore indlicates that the overlying volcanics are at least of Lower Cretaceous age. Upper Cretaceous ages obtained for the volcanics appear to be artificially young due to the effects of metasomitic alterations on these rocks. It also appears that the Tobago metamorphic rocks may be of a Jurassic age, similar to that of equivalent rocks in neighbouring Trinidad.
Plate tectonics of the Northeastern Caribbean sea region1978Schell, B.A.; Tarr, A.C.57(2)Previous geologic literature and the results of the Puerto Rico Seismic Network are synthesized into a plate tectonic model of the northeastern Caribbean Sea region. The Puerto Rico Seismic Network has detected earthquakes which form a well defined zone of seismicity dipping 45 to 50 degrees from the Puerto Rico Trench to a depth of about 150 km under Puerto Rico. This inclined zone of seismicity is interpreted to represent a lithospheric plate. However, focal mechanism solutions have shown that plate motion along the Puerto Rico Trench is directed in an east-to-west sense similar to that expected in a transform fault zone. A plate tectonic model is developed which shows that a portion of the North American plate, originally subducted under the northern Lesser Antilles, underrides the northern edge of the Caribbean plate. When this underriding plate reaches the Hispaniola subduction zone it sinks deeper taking on a plow-shaped configuration. The Puerto Rico type of 'transform' trench is not unique to the Caribbean, but also occurs in the western Aleutian Trench, Puysegur Trench, northern Sunda Trench, and possibly the Scotia Sea region.
Uranium-series ages of Pleistocene marine deposits on the Islands of Curaçao and La Blanquilla, Caribbean Sea1978Schubert, C.; Szabo, B.J.57(2)Sequences of 3, resp. 5 Pleistocene limestone terraces crop out on La Blanquilla and Curaçao. All represent Pleistocene reefs which have been uplifted. Diagenesis of the corals shows a sequence of increasing alteration with elevation (or age) of the terraces. Samples of corals in growth position were collected for dating of the Lower and Middle Terraces of Curaçao, and of the Limestone Terraces 1 and 2 of La Blanquilla. 230Th age determinations indicate that the Lower Terrace of Curaçao (10 m above sea level) and the Limestone Terrace 1 at La Blanquilla (7-10 m above sea level) formed contemporaneously at about 130,000 years ago, and are time-equivalent to Terrace III of Barbados and to the main limestone terrace of La Orchila island, all deposited during the last interglacial. No equivalents of Barbados I and II Terraces were found; they are probably below sea level, indicating that the Netherlands Leeward Islands and La Blanquilla were less uplifted than Barbados. The age of the higher terraces of Curaçao and La Blanquilla is uncertain because of diagenetic changes, but may be estimated as about 325,000 years for the Limestone Terrace 2 of La Blanquilla and about 570,000 years for the Middle Terrace of Curaçao.
Geochemistry of a meromictic brine lake1978Sonnenfeld, P.; Hudec, P.P.57(2)A meromictic lake on the island of Gran Roque, Venezuela, is both thermally and chemically stratified. The density stratification is largely chlorine-controlled, but concentration of major cations is more variable. A statistical evaluation of chemical analyses serves to indicate that differences in concentration between a central depression and a seaward one suggest seepage of seawater into the latter. Additional cations are supplied by drainage, albeit small, from nearby hills composed of basic intrusives.
On two species of Titanosarcolites (Rudistids) from St. James' Parish, NW Jamaica1978Wal, R.J.F. van der57(2)Specimens of Titanosarcolites from St. James' Parish, NW Jamaica, are described. It is shown that in Titanosarcolites new tubes are formed by a process of subdivision of older tubes. The presence of the ligament in the right valve of Titanosarcolites giganteus is established. The internal structures of Titanosarcolites alatus (Chubb, 1967,1971) are described; the species may be intermediate between Antillocaprina and Titanosarcolites giganteus. The genus Titanosarcolites was already known from the Barettia Limestone of Sunderland.
Structural geology of the southeastern blue mountains, Jamaica1978Wadge, G.; Draper, G.57(2)The structural geology of over 100 km of Cretaceous rocks in the southeastern Blue Mountains is described for the first time. Full stratigraphic details have yet to be resolved, but it is apparent that the structural evolution was controlled by different responses to deformation of the two dominant rock types. These are a thick massive unit of basaltic volcanics and a thinly bedded sandstone/siltstone/ mudstone sequence, separated by thin limestones. Synsedimentary deformation is recognized at the boundary of well-bedded argillaceous and thick arenaceous units. Tectonic folds have a dominant NW-SE trend, but variations exist within a mosaic of structural domains. Three fault trends are recognized with modes at 040°, 100° and 155°.
Longshore transport of mud by waves: Northeastern coast of South America1978Wells, J.T.; Coleman, J.M.57(2)Time series measurements of waves and wave/mud interactions along the Surinam coast indicate that waves may play a greater role than previously thought in the suspension and transport of fine-grained sediment on the northeastern coast of South America. Accumulations of fluid mud or slingmud that occur on western flanks of migrating mudbanks affect incoming swell by changing their form from sinusoidal to solitary-like and by preventing wave breaking except for occasional spilling. As solitary like waves propagate over the soft-mud bottom, fluid mud is suspended, resulting in surface suspensate concentrations that exceed 3.103 mg/I. The presence of solitary waves, high suspended-sediment concentrations, and a relatively uniform angle of wave approach throughout the year may lead to extraordinarily high sediment transport rates. If waves are assumed to have a net drift as given by solitary wave theory, then, in taking angle of wave approach and actual measured concentration of sediment in suspension, enough sediment can be transported by waves alone to explain the propagation of mudbanks by fluidmud transport. On the basis of reasonable wave and sediment conditions, it is estimated that up to 70.106 m3 of mud can be transported alongshore each year.
Ammonites from the Curaçao lava formation, Curaçao, Caribbean1978Wiedmann, J.57(2)Ammonites have been discovered for the first time in some thin pelagic intercalations in the Curaçao Lava Formation. Since this is the oldest rock unit which occurs on the island, its dating is of extreme interest. The rather poorly preserved and partly baked ammonites can be attributed to the genera Beudanticeras, Cleoniceras (Grycia), Gastroplites, ?Dipoloceras, Hysteroceras and ?Pervinquieria. The Curaçao Lava Formation is, thus, of upper Middle Albian age. This is consistent with the available equivalent K/Ar-data of 118 ± 10 and126 ± 12 M.A.b.p. (Santamaría & Schubert, 1974), since submarine extruded basalts dated by this method generally give ages somewhat too high. Paleobiogeographic relationships point to the Western Interior and Pacific faunal provinces of North America, and, to a minor degree, to the European Tethys. Moreover, this is exactly the time when Northern and Southern Atlantic became connected for the first time (WIEDMANN & NEUGEBAUER, 1978).
Preliminary report on the occurrence of Tertiary gold-bearing gravels in Surinam1978Wong, T.E.; Lissa, R.V. van57(2)As a result of the recently commenced exploration programme of the Geological and Mining Service of Surinam, gold was discovered in gravels of the Tertiary Coesewijne Formation near Jorka Kreek and Loksie Hatti. These gravels form the base of isolated plateaus along the southern margin of the Coesewijne Formation in the vicinity of major rivers. The gravels were deposited in braided river and alluvial fan systems under semi-arid conditions. It is assumed that at Jorka Kreek both gold and rounded clasts were derived from the Precambrian Rosebel Formation, whereas at Loksie Hatti the gold is derived from local quartz veins. Further evaluation of these placers, now in progress, should reveal whether or not they are economically exploitable.
Some notes on the geomorphology of the shelf of St. Eustatius (Netherlands Antilles)1978Zonneveld, J.I.S.57(2)During the year 1972 H.Ms. "Luymes" of the Royal Netherlands Navy made a hydrographical survey in a part of the N. E. Caribbean. The resulting echograms and maps allowed a more detailed impression of the topography of the sea bottom in this area to be made. In this paper the relief of the shelf of St. Eustatius, with its submarine terraces and ridges, is discussed.
Supplement to the volume of abstracts 8th Caribean Conference Willemstad197857(2)
Foraminifera and parallel evolution - How ofrwhy?1978Gillavry, H.J.M.57(3)Directional changes are distinguished from yes-or-no changes. The latter lack the quality of direction; in the evolution of larger foraminifera they manifest themselves at first at a late ontogenetic stage as individual monstrosities, but lead, by the deuterogenetic mode, to new genera or families. Further evolution within a lineage is characterized by the directional gradualism of neptonic reduction. Various hypotheses why this complex evolution could have been of selective advantage are reviewed; complicating factors are discussed; there is still a large unexplained residue. Gradualism is considered to be rare and to be associated with faunas of low diversity, consisting of related but genetically isolated subunits which react to extra-group factors as one population, but which may evolve through intra-group competition; hence the frequent coexistence of related lineages. Still unexplained is the following of the same evolutionary pathway by forms of no near relationship. This may be due to severe structural limitation of possibilities; one pathway is followed by forms derived from planispiral ancestors, another by forms derived from trochoid ancestors. Three appendices give details on the phylomorphogenesis of Cycloclypeus, notes on lndonesian larger foraminifera, and notes on the stratigraphy of South Sumatra.
Rocks, life and time - an international guide through the stratigraphical labyrinth1978Brouwer, A.57(3)
The interglacial of Frechen I/Rheinland - A section of the Tiglian A-type1978Urban, B.57(3)Palynological investigations of earliest Pleistocene deposits at Frechen, some ten kilometers west of Cologne permit the dating of these sediments in terms of the Dutch biostratigraphic scale. Of special interest is a newly discovered interglacial period, termed the 'Frechen I Interglacial', which indicates a more complicated development of vegetation during the early Tiglian than was hitherto thought.
The interglacial of Frechen I/Rheinland - A section of the Tiglian A-type1978Urban, B.57(3)Large Enclosure
Composite grains in heavy-mineral concentrates and their significance in the differentiation of surface deposits at the confluence of the Maas (Meuse) and Roer (Rur) rivers.1978Bisdom, E.B.A.; Gerlofsma, A.; Poelman, J.N.B.; Riezebos, P.A.57(3)The varying content of composite grains in heavy-mineral concentrates was used for the differentiation of surface sediments in a geomorphologically and pedologically complicate landscape at the confluence of the Maas (Meuse) and the Roer (Rur). West of the Maas valley, these deposits contain quantities of minor importance (<10%), while to the east surface sediments with percentages ranging from 4 to 59 occur. In this latter area a decrease in an easterly direction is suggested from the data. The characteristic high composite content is also found in sediments from the present flood plain of the Maas as well as in an old fluvial deposit of this river (Caberg terrace). It is suggested that the flood plain of the Maas is the source of the surface deposits being found to the east, and that similar deposits west of the Maas valley come from another source area. Finally the possible use of composites as provenance indicators is discussed briefly.
Composite grains in Maas (Meuse) sediments: a survey and a discussion of their opaque components1978Riezebos, P.A.; Bisdom, E.B.A.; Boersma, O.57(3)The opaque mineralogy of composite grains in acid-treated heavy-mineral concentrates from sediments of the river Maas (Meuse) was studied in reflected light and by SEM-EDXRA analysis. Secondary rutile, secondary ilmenite and hematite constitute the subtranslucent to opaque matter in these composites, which principally represent actual rock fragments. This suggests that the sediments investigated contain products of rather freshly disintegrated rocks. The opaque components enable two important groups of rock fragments to be distinguished: a major group characterized by secondary rutile, secondary ilmenite and their intergrowths; and a minor group with exclusively hematite.
Microfossil biostratigraphy and stage-stratotypes of the Cretaceous1978Sissingh, W.57(3)Correlation of the most recent Cretaceous zonations based on calcareous nannoplankton, planktonic foraminifera and calpionellids allows more precise determination of the relative position of some Cretaceous stage-stratotypes in the standard chronostratigraphical scale. In particular, those of the Santonian, Campanian and Maastrichtian stratotypes seem to be very limited in time-span. It is possible to overcome these limitations and to some extent also the problems concerning their recognition and traceability by a pragmatic extension of the type-sections and by the introduction of auxiliary hypostratotypes in the type areas. However, it is concluded that designation of one or more independent reference sections for Upper Cretaceous stages is a preferable alternative which should receive more attention. In this way also a more useful section could be proposed for the Cenomanian, Turonian and Coniacian stages.
Isotopic evidence for a Middle to Late Pliocene age of the cordierite granite on Ambon, Indonesia1978Priem, H.N.A.; Andriessen, P.A.M.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Hutchison, C.S.; Verdurmen, E.A.T.; Verschure, R.H.57(3)Rb-Sr dating of the pair whole-rock/biotite from the cordierite-bearing granite on Ambon (Moluccas, E. Indonesia) yields an age of 3.3 ± 0. 1 Ma with initial 87Sr/86Sr = 0.7221. The K-Ar age of the biotite is 3.8 ± 0.2 Ma (ages based upon the constants recommended by Steiger & Jäger, 1977). A Middle to Late Pliocene age can thus be assigned to the granitic magmatism
Precambrian palaeosols at the base of the Roraima formation in Surinam1978Kroonenberg, S.B.57(3)A red transition zone with granitic fragments between the Roraima sandstones and the underlying granite at Kappelsavanna, Tafelberg and Emma Range is argued to represent a pre-Roraima palaeosol. The mineralogical and micromorphological characteristics of the palaeosol indicate an origin in an arid or semi-arid climate.
Late Cenozoic history of Eastern Crete and implications for the geology and geodynamics of the southern Aegean area1978Fortuin, A.R.57(3)An interpretation is given of the structural setting and the sedimentary history of the Middle Miocene - Quaternary deposits in eastern Crete (Ierapetra region). The present tectonic structure, characterized by normal faults in W-E and NE-SW directions, is dominated by a central NE-SW graben, which seems to mark a dislocation in the curvature of the Aegean Arc. In Late Serravallian – Early Tortonian times deposition drastically changed from terrestrial to open marine, with turbidites, filling in a graben that extended over the southern half of the region. The sources of sediment supply then shifted from east to west and slices of sediments (in part of pre-Neogene age) slid from the uplifted blocks in the north to the central parts of the region, where a submarine valley was formed. A seismic reflection profile south of Crete may show analogous gravity sliding in the Neogene. From the Late Tortonian till the Pliocene carbonate sedimentation took place. A gradual shallowing followed, which ended with deposition of the well known Messinian facies. Unstable tectonic conditions controlled the sedimentation until the Early Pliocene, when quiet open marine sedimentation returned. In the early Late Pliocene tectonic uplift started to separate Crete as a horst from the surrounding seas. Although strong, this general uplift was periodically interrupted.
Bioerosion by polydora (Polychaeta, sedentaria, vermes) off Helgoland, Germany1978Pers, J.N.C. van der57(3)The boring activities of Polydora BOSC. 1802, are an important agent in bioerosion. Trace fossils attributed to this worm are very common. From data collected on Recent representatives of Polydora ciliata JOHNSTON 1838, it is evident that the boring mechanism of this worm is to be interpreted as a combination of mechanical and chemical processes. Dodecaceria, another genus of polychaete worms, is considered to be able to bore chemically in lime-rich substrata.
Preface - Key-notes of the MEGS-II1978Loon, A.J. van57(4)
Opening adress1978Tieleman, W.H.J.57(4)
Magnesium-salt exploration in the northeastern Netherlands1978Coelewij, P.A.J.; Haug, G.M.W.; Kuijk, H. van57(4)Magnesium-bearing salts occur in the Zechstein Basin in the northeastern Netherlands at a depth of 1500 to 2500 m. Exploration has resulted in the discovery of significant amounts of this salt which will be exploited by solution mining for the production of refractory grade magnesiumoxide. Of the four main evaporite cycles, Zechstein III (the ore-bearing cycle) is fully developed and contains the magnesium salts carnallite (MgCl2.KCI.6H2O), bischofite (MgCl2.6H2O) and kieserite (MgSO4.H2O). The salt sequence has been affected by halokinesis, resulting in salt domes and other structures. The magnesium-bearing layers were thickened towards the top of the structures, thus forming prime targets for exploration. Exploration techniques comprise seismic surveys and rotary drilling. Conventional seismic methods adequately define depth and structural configuration, whilst high-resolution seismic wavelet processing is used for the identification of the magnesium-salt layers on the seismic section and determination of thickness. Seismic sections are converted into acoustic impedance sections which are calibrated from acoustic impedance logs. These in turn are derived from velocity and density measurements in bore holes. The mineral composition, ore grade, and thickness can be accurately determined by petrophysical well-logging: in particular formation density, gamma ray, and sonic logs. Results are calibrated by chemical analysis of drillcores.
Exploration for gas in the Irish area1978Colter, V.S.57(4)Exploration for gas between the Isle of Man and the mainland has confirmed the presence of a Permo-Triassic basin, with sediment thicknesses in excess of 3,000 m. The section can be correlated with the onshore succession and consists of the following: 'Keuper' Marl + Saliferous series (eroded), 'Keuper' Waterstones, 'Keuper' Sandstone, St. Bees Sandstone Manchester Marl and equivalent halite Collyhurst Sandstone and equivalent shales. Drilling and seismic work have shown abrupt thickness changes across some faults, which may show reversals of throw at different times. Sonic velocities in shales at the base of the 'Keuper' Marl suggest depths of burial of more than 4000 m, pointing to the possibility that a thick younger Mesozoic section was once present. Diagenesis of the sandstones includes calcite and quartz cementation and the development of platy illite. Ga