Showing papers in "Geological Magazine in 1958"
82 citations
TL;DR: In this article isolated masses of highly olivine-rich lavas within a dominantly basaltic series of pillowed flows have been found in the northern foothills of the Troodos Igneous Massif.
Abstract: Small isolated masses of highly olivine-rich lavas within a dominantly basaltic series of pillowed flows have been found in the northern foothills of the Troodos Igneous Massif. The rock is characterized by abundant phyric olivine usually set in a glassy, basaltic groundmass. Both intrusive and extrusive varieties of the rock have been found. It is suggested that the rock originated as a melt, possibly from the Troodos ultrabasic complex. Comparison is made with the serpentine lavas of Turkey.
76 citations
TL;DR: In this article, microspore assemblages from the Six Inch Mine coal seam and associated shales at Quarnford, Staffordshire, northern England were collected and studied.
Abstract: Microspore assemblages from the Six Inch Mine coal seam and associated shales at Quarnford, Staffordshire, northern England, were collected and studied. Three new genera, Discernisporites, Mooreisporites, and Proprisporites, and seven new species are erected and described. The maceration techniques developed for obtaining specimens from the shales in comparable condition to those from the coal seam are also described. It was found that spores belonging to the genus Florinites were dominant in the marine shales and that the variety of species in the shales was greater than that of the seam. Chaloner9s discussion gives an alternative hypothesis for the high percentage of conifer pollen in the marine shales relative to that of the coal and nonmarine shales.
73 citations
TL;DR: The combination of intense weathering and sub-surface erosion with ensuing contraction of the debris occurring just below the piedmont angle may be sufficient to explain the maintenance of this angle during slope retreat.
Abstract: Sub-surface erosion is intensely active in weathered granite debris at the scarp foot of Jebel Qasim. Powerful flushes of sub-surface water after heavy rain remove much of the decomposing feldspar partly by solution and partly by mechanical eluviation. The sedentary debris gradually contracts as the feldspar is removed and when removal is nearing completion the debris may become compacted. The compacted debris occupies less than 40 per cent by volume of the granite from which it was derived.The upper fringing pediment around this hill is mantled by moist incoherent debris holding small local pockets of water which persist throughout the dry season. Annual recharge of this sub-surface water ensures intense weathering in the debris.The combination of intense weathering and sub-surface erosion with ensuing contraction of the debris occurring just below the piedmont angle may be sufficient to explain the maintenance of this angle during slope retreat.
70 citations
TL;DR: A large part of the Wealden in southern England does not contain ostracods, mollusks, or vertebrates, but has been found to contain fossil plant microspores and megaspores and these are now used to delineate stage boundaries and to correlate the stages with the lower Cretaceous succession in Lincolnshire and the Netherlands as mentioned in this paper.
Abstract: A large part of the Wealden in southern England does not contain ostracods, mollusks, or vertebrates, but has been found to contain fossil plant microspores and megaspores. These are now used to delineate stage boundaries and to correlate the stages with the lower Cretaceous succession in Lincolnshire and the Netherlands. The boundaries of the Berriasian, Valanginian, Hauterivian, Barremian, and Aptian are discussed, though not necessarily firmly located, and the point is made that much more work needs to be done.
44 citations
TL;DR: Carboniferous and Permian fossils collected from Central Vestspitsbergen between 1938 and 1957 are listed according to formations and the age of each is assessed from these determinations as mentioned in this paper.
Abstract: Carboniferous and Permian fossils collected from Central Vestspitsbergen between 1938 and 1957 are listed according to formations and the age of each is assessed from these determinations. Resting unconformably on folded Devonian or metamorphosed Hecla Hoek the succession begins with plant-bearing continental facies and passes upwards into a marine succession with fusuline, coral and brachiopod faunas in limestones and dolomites associated with evaporites and cherts. Correlation with rocks elsewhere in Svalbard, which has been effected largely by lithological facies, is reassessed on palaeontological evidence; this consists of a sequence of plants from approximately Tournaisian to Namurian; of fusulines from the Fusulina Zone to the Pseudoschwagerina Zone, with the Carboniferous-Permian boundary falling in the middle of the Wordiekammen Limestones; and of brachiopods above this. The youngest fossils may be Upper Permian. The succession has few breaks and with further study will contribute to the correlation of Russian, West European, Greenland, and American rocks.
36 citations
TL;DR: A study of Stephanocerataceae and Perisphinctaceae of the Middle Jurassic demonstrates that the structure of the septa comprises a complex vault and pillar system which is functionally adapted to the dimensions of the tube so as to give maximal stability to the shell.
Abstract: A study of Stephanocerataceae and Perisphinctaceae of the Middle Jurassic demonstrates that the structure of the septa comprises a complex vault and pillar system which is functionally adapted to the dimensions of the tube so as to give maximal stability to the shell. Only through a study of the septum can we interpret the different forms of the suture and discriminate between important and unimportant features. Different septa may have analogous sutures, especially in the external parts. These septal patterns are strikingly consistent within subfamilies or families even where other features suggest overlap between the groups. Some parts of the septum are not adapted, but either retained from earlier ontogeny or inherited, and constitute vestigial (genotypic) characters distributed through taxons.These empirical results have been applied to the taxonomy of some groups of hitherto doubtful systematic position (Cadomitinae, Normannitinae, Sphaeroceratinae, Parkinsoniidae, Spiroceratidae).
35 citations
TL;DR: The compositions of pyroxene pairs in pyroxenite and gneiss from Scourie, Scotland, metamorphosed picrite basalt from Kilauea, hornfels from the Oslo district, and granulite from Ardnamurchan, Scotland have been analyzed chemically and inferred optically.
Abstract: The compositions of pyroxene pairs in pyroxenite and gneiss from Scourie, Scotland, metamorphosed picrite basalt from Kilauea, hornfels from the Oslo district, and granulite from Ardnamurchan, Scotland, have been analyzed chemically and inferred optically. The tie-lines of these pairs have been ploted in the diagram of the system wollastonite-enstatite- ferrosilite, and the trends are compared with those found for plutonic igneous associations.
28 citations
TL;DR: In this article, the lower middle Hecla Hoek succession in Ny Friesland was established and reported, and the nature of the contact with the lower Hoek is considered, and Veteranen limstones and quartzites of the lower Veteranen series, the Galoistoppen beds and Cavendishryggen limestones and quartzite of the middle Veteranen Series, the Glasgowbreen quartzites and graywackes of the upper Veteranenseries, and Enpiggen beds and Fulmarberget shales of the Oxfordbreen series are
Abstract: Between 1949 and 1955, the lower middle Hecla Hoek succession in Ny Friesland was established and reported. Examination of the series in various localities during these years and subsequent field work in 1956 and 1957 have yielded additional details which are here reported. The nature of the contact with the lower Hecla Hoek is considered, and the Veteranen limestones and quartzites of the lower Veteranen series, the Galoistoppen beds and Cavendishryggen limestones and quartzites of the middle Veteranen series, the Glasgowbreen quartzites and graywackes of the upper Veteranen series, and the Enpiggen beds and Fulmarberget shales of the Oxfordbreen series are described. The section is compared with that in Nordaustlandet. The succession as a whole shows frequent repetition of a limited number of rock types and probably represents a distinctive phase in the development of the Ny Friesland geosyncline.
27 citations
TL;DR: In this article, the distribution of oblique-slip shears exposed in the south-western part of the Midland Valley of Scotland was analyzed. But the results were limited to a single set of commonly occurring normal-dextral shears.
Abstract: Primary shears with oblique-slip displacement can only arise by failure after a rotation of two of the three principal axes of stress from an expected vertical and horizontal position relative to the earth's crust, and are either normal-wrench or thrust-wrench hybrids. As a consequence of a full 90° clockwise or anticlockwise rotation, the changes in pitch of striations on slicken-sided fault planes belonging to both categories are stereographically represented by two small circle courses which are ∠90°–o apart for the normal-wrench association, and ∠180°–o apart for the thrust-wrench one: ∠o being the angle of internal friction. Using these assumptions to analyse the distribution of oblique-slip shears exposed in the south-western part of the Midland Valley of Scotland, it appears probable that two unrelated sets of commonly occurring normal-dextral shears are of primary origin, for the inferred azimuthal orientations of the principal axes of stress are remarkably close to those estimated for other, more orthodox tectonic features found elsewhere in the Midland Valley and appropriately absent in the south-west.
26 citations
TL;DR: Sedimentary dikes occur in the exposures of the Appin phyllite-limestone along the shore of Loch Leven south of Fort William, western Scotland as mentioned in this paper.
Abstract: Sedimentary dikes occur in the exposures of the Appin phyllite-limestone along the shore of Loch Leven south of Fort William, western Scotland. Both downward and upward injected dikes are present; the former are probably contemporaneous with deposition of the beds, the latter post-depositional. The dikes are invariably associated with slumped rocks that are typical of unstable marginal geosynclinal areas. The term "cavity filling dikes" suggested by Fairbridge in 1946 is not recommended, but his suggestion that sedimentary dikes are associated with slumped deposits of marginal geosynclinal areas is confirmed.
TL;DR: An abundant fauna characterizes the upper Jurassic Kurnub limestone of the Wadi Hathira area in southern Israel as discussed by the authors, where the section consists of Eligmus-Erymnoceras limstones and marls.
Abstract: An abundant fauna characterizes the upper Jurassic Kurnub limestone of the Wadi Hathira area in southern Israel. The section consists of Eligmus-Erymnoceras limestones and marls, Eligmus-Grossouvria marls with limestone, Somalirhynchia-Putealiceras marls and limestones, Shuqraia limestones with marl, and Cladocoropsis marls and limestones. The faunas are listed.
TL;DR: A re-examination of the Moine-sub-Moine boundary of the Morar dome shows it to be a zone of transition between two metamorphic states as mentioned in this paper.
Abstract: "A re-examination of the Moine-sub-Moine boundary of the Morar dome shows it to be a zone of transition between two metamorphic states. Some notes on the structure accompany a mineralogical description of the changes across the boundary; discussion is made of evidence that the metamorphic boundary transgresses the geological boundaries. The schists of the core are thought to be in a lower metamorphic state than those of the envelope."
TL;DR: In the Tertiary rocks of Victoria, a continuous sequence of 11 faunal units characterized by pelagic foraminifers, ranging from upper Eocene to middle Miocene, has been recognized as mentioned in this paper.
Abstract: In the Tertiary rocks of Victoria, a continuous sequence of 11 faunal units characterized by pelagic foraminifers, ranging from upper Eocene to middle Miocene, has been recognized. These faunal units are based chiefly on the appearanice of species of Globigerina, Globogerinoides, Globoquadrina, Orbulina, or Biorbulina. Each unit is briefly described. Comparison is made with other regions-- New Zealand, Caribbean, Saipan, Europe, and North America--where some features of the same sequence of events have been noted. Eventually, intercontinental correlation of Tertiary rocks may be possible on the basis of first appearances of pelagic foraminifers.
TL;DR: In this paper, minor folds with axial directions at a marked angle to the regional fold plunge have been observed on the Craignish peninsula, western Scotland and on the Rosguill peninsula, northwest Donegal, western Ireland, and are described and discussed as discordant structures.
Abstract: Minor folds with axial directions at a marked angle to the regional fold plunge have been observed on the Craignish peninsula, western Scotland, and on the Rosguill peninsula, northwest Donegal, western Ireland, and are described and discussed as discordant structures. The folds of the Craignish peninsula are thought to have resulted from rotation of a detached structure, originally concordant, into a new position. Some of those of the Rosguill peninsula are thought to have been produced by the same process; others are attributed to refolding which caused development of a new schistosity in the matrix. Most of the discordant structures are no longer attached to their original roots, and in such cases of detached structures, care should be used in analysis.
TL;DR: Petrographic study of rock specimens collected across the axis of the Quihita-Cunene gabbro intrusion from Pocolo to Gambos, and to the south near the Cunene river, Angola, indicates that the Gabbroic massif is probably a single intrusion differentiated into a series of layered rocks as discussed by the authors.
Abstract: Petrographic study of rock specimens collected across the axis of the Quihita-Cunene gabbro intrusion from Pocolo to Gambos, and to the south near the Cunene river, Angola, indicates that the gabbroic massif is probably a single intrusion differentiated into a series of layered rocks. Rhythmic and cryptic layering are present. Comparison is made with the Great Dyke of Southern Rhodesia.
TL;DR: Pelites in the aureoles of intrusions of basic magma in Connemara, Ireland, have been strongly metasomatized, dealkalized, and desilicated as mentioned in this paper.
Abstract: Pelites in the aureoles of intrusions of basic magma in Connemara, Ireland, have been strongly metasomatized, dealkalized, and desilicated. Farther from the intrusions, the pelites show very little thermal metamorphism, but are similarly poor in silica and rich in alumina and total iron. Study of the chemical composition of pelites from southern Connemara and comparison with pelites on the north flank of the antiform, where the metamorphism is of a different facies, show little difference, and it is concluded that the compositions reflect original sedimentation features.
TL;DR: In the lower Severn valley, the highest and oldest terrace was designated the Woolridge in 1938 as mentioned in this paper, and the gravels have been reexamined and found to be of two different ages.
Abstract: In the lower Severn valley, the highest and oldest terrace was designated the Woolridge in 1938. The gravels have been reexamined and found to be of two different ages. The older gravels are probably outwash of a Severn valley glacier; the younger series consists of stream gravels. It is proposed to call the older series the Woolridge, and the slightly younger gravels, the Upleadon. Both are composed chiefly of Bunter pebbles, but the younger series also has abundant Silurian material.
TL;DR: In New Zealand where the former landscape type is typically developed, there has also been quite strong "periglaciation" and in Europe running-water erosion cannot but have operated to some extent in interglacial ages as discussed by the authors.
Abstract: Alternation of morphogenetic systems conditioned by wide swinging of climatic belts equatorward and poleward has been used to explain otherwise puzzling relict forms in many regions. A characteristic finely dissected landscape relief prevalent in some middle-latitude regions is in strong contrast with smoothed, coarse-textured, whalebacked, relatively featureless relief in others, notably western Europe, which are now in the humid-temperate zone. This latter is believed to be relict from the periglacial regimes of Pleistocene ice ages. In New Zealand where the former landscape type is typically developed, there has also been quite strong “periglaciation”, and in Europe running-water erosion cannot but have operated to some extent in interglacial ages. It appears that the periglacial smoothing has been pushed to the extreme limit in Europe but that its effects have been neutralized in New Zealand by the vigour of dissection in the alternating warm ages. Periglacial smothering, or “fossilization”, of fine-textured relief, which has been followed by renewed fine dissection, is very common at Wellington, New Zealand. The reasons are not clear why running water should have been (and should still be) more efficient in dissecting the New Zealand landscape than that of Europe, so that the relict periglacial landscape remains intact in the latter region.
TL;DR: A bone found in the peat near King9s Lynn, Norfolk, has been identified as belonging to a pelican as discussed by the authors, which is the fifth fossil record from east Anglia but it is the first to be accurately dated, and it can be correlated with Godwin9s pollen zone VII-VIII (Iron Age).
Abstract: "A bone found in the peat near King9s Lynn, Norfolk, has been identified as belonging to a pelican. This is the fifth fossil record from east Anglia but it is the first to be accurately dated, and it can be correlated with Godwin9s pollen zone VII-VIII (Iron Age). Other fossil pelican bones from east Anglia and Somerset are identified as those of the Dalmatian pelican rather than the white pelican which now visits parts of north-west Europe."
TL;DR: In this article, the upper Hecla Hoek group is divided into the Polarisbreen and Oslobreen series and the dolomites are, at least in part, lower Cambrian; the middle and most of the lower OSLobreen limestones are lower Ordovician.
Abstract: The upper Hecla Hoek group of the Hecla Hoek succession in Ny Friesland, northeast Spitsbergen, is subdivided into the Polarisbreen and Oslobreen series. A fauna collected from the Oslobreen dolomites and limestones in 1956 is here described and the age range shown to be greater than previously suggested. The dolomites are, at least in part, lower Cambrian; the middle and most of the lower Oslobreen limestones are lower Ordovician. The fauna contains trilobites belonging to Hystricurus, Bolbocephalus, and Bathyurus, brachiopods belonging to Obolus and Archaeorthis, gastropods belonging to Macluritella and Helicotoma, and the cephalopod Salterella.
TL;DR: The Woolhope inlier, near Ledbury, Wales, has several zones of fragmentary beds in the Ludlovian (Silurian) strata that have yielded thelodont and acanthodian denticles as discussed by the authors.
Abstract: The Woolhope inlier, near Ledbury, Wales, has several zones of fragmentary beds in the Ludlovian (Silurian) strata that have yielded thelodont and acanthodian denticles. Thelodont remains have also been found in the Usk and Lye inliers at the base of the Dayia shales and very probably occur at this horizon over the entire area. While concentrations of fish remains are not found in the Llandovery or Wenlock series, they are undoubtedly present though scattered.
TL;DR: New occurrences of kyanite-bearing schists in the Moine Series in southern Ross-shire demonstrate the order of appearance of the typomorphic minerals staurolite, kyanitic, garnet, and sillimanite, and are of significance in elucidating the relationship of regional metamorphism to orogenesis.
Abstract: New occurrences of kyanite-bearing schists in the Moine Series in southern Ross-shire demonstrate the order of appearance of the typomorphic minerals staurolite, kyanite, garnet, and sillimanite, and are of significance in elucidating the relationship of regional metamorphism to orogenesis. The scarcity of kyanite in the Northern Highlands is the result of both isochemical and allo-chemical effects, and its distribution is compared with that of its polymorphs andalusite and sillimanite .
TL;DR: In this paper, the Devonian sandstones are overlain unconformably by a series of Permo-Carboniferous rocks, and the major lithologic horizons can be recognized in nearby areas, and a tentative correlation is made.
Abstract: On the peninsula between Ekmanfjorden and Dicksonfjorden, Spitsbergen, Devonian sandstones are overlain unconformably by a series of Permo-Carboniferous rocks. These consist of 200 meters of limestone, with a thin basal conglomerate and frequent layers of nodular chert, a succession of 300 meters of beds of dolomite, limestone, gypsum, and anhydrite, and 150 meters of chert. Dolerite sills outcrop in the area and are more widespread than previously mapped. They occur at a constant stratigraphic level, but are not continuous. The major lithologic horizons can be recognized in nearby areas, and a tentative correlation is made, which can probably be extended later.
TL;DR: Karroo sedimentation in the Zambezi valley area between Kafue and Livingstone, Northern Rhodesia, took place on a mature surface developed on an intracratonic basin of the African shield.
Abstract: Karroo sedimentation in the Zambezi valley area between Kafue and Livingstone, Northern Rhodesia, took place on a mature surface developed on an intracratonic basin of the African shield. The formations comprise the lower Wankie sandstone (upper Carboniferous), Gwembe coal formation, Madumabisa mudstone, Escarpment grit, upper Karroo sandstone, and Batoka basalt (lower Jurassic). Structural development since Karroo time is outlined, and it is thought that the present valley is a downwarped part of the peneplain which forms the plateau adjacent to the northwest.
TL;DR: In this article, the effects of lunar or tidal pull on the solid surface of the earth are accumulative and initially responsible for upwarping, mountain building, and other types of deformation.
Abstract: The view is put forth that the effects of lunar or tidal pull on the solid surface of the earth are accumulative and initially responsible for upwarping, mountain building, and other types of deformation. Evidence of raised beaches in England, of strata in the Swiss Alps, and of various rocks in Jamaica, Barbados, Trinidad, and New Zealand is cited.
TL;DR: In this paper, the discovery of a reworked specimen of middle Liassic Pleuroceras transiens in the basal Cretaceous conglomerate at a roadside exposure in the Murlough bay area, Ireland.
Abstract: Records the discovery of a reworked specimen of middle Liassic Pleuroceras transiens in the basal Cretaceous conglomerate at a roadside exposure in the Murlough bay area, Ireland.
TL;DR: The recent discovery of a plant zone containing Lyginopteris stangeri at Penderyn, on the North Crop of the south Wales coal field, as well as other plant occurrences in the Neath valley area, indicates the presence of the Eumorphoceras stage of the Namurian (upper Carboniferous).
Abstract: The recent discovery of a plant zone containing Lyginopteris (Calymmatotheca) stangeri at Penderyn, on the North Crop of the south Wales coal field, as well as other plant occurrences in the Neath valley area, indicates the presence of the Eumorphoceras stage of the Namurian (upper Carboniferous), which requires reinterpretation of the Avonian and Namurian succession.