bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gastropoda from the Karroo Beds of Southern Rhodesia
Authors: Cox L. R. 
Published: May 2009

AbstractThe occurrence, very rare in Karroo rocks, of a gastropod species in the Lower Beaufort stage (Upper Permian) of Southern Rhodesia is recorded. It is a small form apparently related to species found in the Tartarian stage of the Russian Permian. These species have been described under extinct marine genera, but on account of their morphology and non-marine habitat this is thought to be inappropriate. The new species much resembles some representatives of the modern genus Hydrobia, not previously recognized in pre-Mesozoic rocks, and it has been decided to describe it as a new species, Hydrobia gondwanica.
Age of the Wealden in North-Western Europe
Authors: Allen P. 
Published: May 2009

AbstractThe Wealden of the Weald is mainly post-Tithonian/pre-Aptian in age. The formation probably comprises the fullest non-marine record of the interval in north-western Europe, spanning most of Berriasian (Infra-Valanginian), Valanginian, Hauterivian and Barremian time. It is well suited to be the standard succession for purposes of direct correlation.The term “ Wealden ” should, if used for beds outside the English basin, be applied only to those non-marine formations (1) clearly lying within the Berriasian–Barremian range and, if possible, (2) correlatable directly with the standard. Otherwise “ Wealden facies ” should be used.Beds claimed as “ Wealden ” elsewhere in north-western Europe are examined in this light.
The Mode of Occurrence of Sillimanite in the Glen District, Co. Donegal
Authors: Tozer C. F. 
Published: May 2009

AbstractSillimanite produced by the contact action of the Donegal Granite shows varied textural and time relationships with the other minerals of the schists in which it occurs. Early Sillimanite was formed in the main stage of metamorphism by destruction of biotite, K, Fe, and Mg being expelled in the process. A later influx of new K from the granite led to the growth of muscovite metacrysts. This was associated with destruction of part of the early Sillimanite, recrystallization of part, growth of a new crop of Sillimanite needles, and formation of muscovite-sillimanite intergrowths.
Glacial Melt-Water Spillways near Kidsgrove, Staffordshire
Authors: Yates E. M. 
Published: May 2009

AbstractAs a result of the drainage contest between the Weaver headstreams and the headstreams of the Trent the west facing edge of the Potteries coalfield has been breached in a number of places, in particular at Kidsgrove. During the last retreat of the ice the Kidsgrove breach came ultimately to act as a spillway for the large lake contained between the ice and the coalfield. Before the breach was uncovered, however, a number of spillways were cut further east.
The Granite Problem: Evidence from the Quartz and Feldspar of a Tertiary Granite
Authors: Tuttle O. F. , Keith M. L. 
Published: May 2009

AbstractThe inversion temperatures of the quartz from twenty-five specimens of the Beinn an Dubhaich granite have been measured and found to correspond to the inversion temperatures of quartz from rhyolites previously studied. Optical and X-ray studies of the alkali and plagioclase feldspars indicate high temperature modifications. The Beinn an Dubhaich granite has the textural and compositional features of a granite together with mineralogical features normally associated with rhyolitic rocks. The results serve to emphasize that methods are now available which make it possible in some cases to determine whether a particular granite was formed by metamorphism of sediments or by crystallization of a magma. It is concluded that the older granites and those which crystallized at greater depths probably have undergone considerable rearrangement of their mineralogical and textural features subsequent to primary crystallization.
Alkaline Syenites at Ruri, South Nyanza, Kenya
Authors: Pulfrey William 
Published: May 2009

AbstractAlkaline syenites from the Ruri Hills in Western Kenya are described, and the hypothesis advanced that their present constitutions have been developed partly by replacement. The syenites occur as dykes and small plugs associated with ring complexes of carbonatites which, together with agglomerates, largely form the hills, and are presumed to be congeneric with an ijolite mass at Usaki.
On the Graphical Representation of Differentiation Trends in Igneous Rocks
Authors: Simpson E. S. W. 
Published: May 2009

AbstractThis paper describes a revised method of plotting analyses of igneous rock suites using the Mafic and Felsic Indices as defined. A composite M–F diagram has certain advantages over the triangular iron-magnesia-alkalis diagram and enables a genetic distinction to be made between the tholeiitic and calc-alkaline series.
The Pegmatites of Trolvis Quarry, Carnmenellis, Cornwall
Authors: Hosking K. F. G. 
Published: May 2009

AbstractThe pegmatites of Trolvis Quarry, Carnmenellis, are small lenticular masses which were developed before the joints of the associated granite. Both mineralogically simple and complex types occur: the latter are drusy. Whilst the earlier minerals lining the druses may have crystallized in a closed system, the later minerals were clearly deposited from a moving phase. The disposition of the later minerals was largely determined by earlier crystals acting as baffles to the mineral-depositing agents. The pegmatites appear to occupy spaces formed by the solution of the granite by a pegmatitic fraction of the magma.
The Structure of the Granophyric Quartz-Dolerite Intrusion of Centre 2, Ardnamurchan and the Problem of Net-Veining
Authors: Wells M. K. 
Published: May 2009

AbstractThe Quartz-dolerite intrusion of Sgùrr nam Meann, Ardnamurchan, is shown to be a ring-dyke which has sill apophyses extending from its outer wall. This is a form of intrusion which has not been recognized before, and its field relations are described in detail. The quartz-dolerite is extensively veined by acid rocks which are ubiquitous in all parts of the intrusion, and most abundant in the sills. From the evidence of the distribution and nature of the veining it is concluded that the acid and basic components of the intrusion must have been ernplaced simultaneously. It is suggested that a gas-charged, acid residual magma may have separated from a crystallizing basic parent under the influence of sudden reductions of external pressure acting upon the system.
Tectonic Features of the Hecla Hook Formation to the South of St. Jonsfjord, Vestspitsbergen
Authors: Weiss L. E. 
Published: May 2009

AbstractA structural study of rocks of the Hecla Hook formation in the area of Forlandsundet of Vestspitsbergen reveals the presence of two B–axes. The earlier (B1) trends roughly east–west and affects only the Hecla Hook formation; the later axis (B2) trends roughly north–south, and affects also rocks of Carboniferous age. It is suggested that B1 is the main “Caledonian” axis in this area, and that B2 and the roughly north–south “grain” of the rocks concerned are Lower Tertiary phenomena.
Magnetic Correlation in Volcanic Districts
Authors: Hospers J. 
Published: May 2009

AbstractAlternating zones of normal and reverse natural permanent magnetization, each comprising about twenty-five flows, have been found in the Tertiary and Quaternary plateau basalt series of Iceland. The techniques for measuring this permanent magnetization are discussed and some results shown. It is suggested that zones of normal and reverse magnetization may be useful for correlation purposes in volcanic districts. Some other possible applications of rock magnetism are mentioned.
From Dolerite to Diorite: Older Granite Activity near Ellon, Aberdeenshire
Authors: Farquhar O. C. 
Published: May 2009

AbstractHornblende-schists, probably intruded as dolerite sills, have been permeated by trondhjemitic material. Conversion to rocks of dioritic aspect is the end-stage of this process, but the intermediate stages are more common. The conversion has been effected with little displacement so that all varieties can be observed in their correct sequence.
“Hutton's Unconformity,” Isle of Arran
Authors: Tomkeieff S. I. 
Published: May 2009

AbstractIt is shown that “Hutton's Unconformity” on the Isle of Arran has been misinterpreted. The assumed plane of unconformity is in reality the plane separating the Dalradian schists from the upper-most zone of schists impregnated with and cemented by calcareous material. The true plane of unconformity is situated some 4 feet above this plane.
Oblique-Slip Faults and Rotated Stress Systems
Authors: Williams Alwyn 
Published: May 2009

AbstractPrimary 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°–ø apart for the normal-wrench association, and ∠180°–ø apart for the thrust-wrench one: ∠ø 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.
The Geology of the Land between Ekmanfjorden and Dicksonfjorden in Central Vestspitsbergen
Authors: Bates D. E. B. , Schwarzacher W. 
Published: May 2009

AbstractThe peninsula between Ekmanfjorden and Dicksonfjorden has been mapped geologically. Devonian sandstones are overlain unconformably by a Permo-Carboniferous sequence of limestones (200 m.) and dolomites and gypsum (300 m.). This is followed by more than 150 metres of Permian cherts. The strata show a slight but consistent dip towards the SSE. A fault having the trend of this dip has been proved in Ekmanfjorden. Sills are intruded in the higher levels of the succession and it is suggested that the intrusions are contemporaneous with the faulting. By comparing the lithology the area can be correlated with the known sections of Billefjorden and Kongsfjorden.
Further Data on the Petrology of the Pelitic Hornfelses of the Carn Chuinneag–Inchbae Region, Ross-shire, with Special Reference to the Status of Almandine
Authors: Harker R. I. 
Published: May 2009

AbstractThe pelitic hornfelses surrounding the Carn Chuinneag–Inchbae complex have, with the other rocks in the area, been subjected to the regional metamorphism which affected the Moine Series as a whole. The minerals of the original hornfelses have reacted to form assemblages which are typical of regional rather than purely thermal metamorphism although the massive structure of the hornfelses is well preserved.By studying the changes which took place in the hornfelses during the regional metamorphism it has been possible to deduce the most likely mineral assemblages indigenous to the original hornfelses.The results of the chemical analyses of some of the pelitic hornfelses are presented and chemical data on some of the garnets are given. It is considered unlikely that all the garnets in the hornfelses, which are essentially almandines, formed as a result of the earlier contact metamorphism: some at least probably occur as a result of the later regional metamorphism.
The Plutonic History of the Aswan Area, Egypt
Authors: Gindy A. R. 
Published: May 2009

AbstractThe coarse porphyritic Aswan Granite used in many ancient Egyptian monuments has been held to intrude a tract of gneisses and schists. It is suggested in this paper that the granitic body was formed during a phase of granitization which followed the folding and metamorphism responsible for producing the gneisses and schists. A part of the granite retains mimetic structures inherited from the pre-existing rocks, but the southern part became mobile and developed a new structure. The intrusion of a magmatic granite in dykes and sheets followed the phase of granitization.
The Structure and Development of Peiragraptus fallax, gen. et sp. nov. A New Graptolite from the Ordovician of Canada
Authors: Strachan Isles 
Published: May 2009

AbstractA new genus, Peiragraptus, is proposed for graptolites having a partial diplograptid development and mainly uniserial rhabdosome. A growth series of the new species P. fallax from the Upper Ordovician of Anticosti is described.
Devonian Goniatites from North Cornwall
Authors: House M. R. 
Published: May 2009

AbstractA study of Devonian faunas from North Cornwall shows that a considerable area of beds hitherto regarded as Upper Devonian are of Middle Devonian age. Goniatite localities at Trevone Bay and Portquin correlate with the Upper Maenioceras Stufe of Germany: other localities within the area mapped as Grey Slate by the Survey are also Middle Devonian. Only the area marked as Purple and Green Slate by the Survey has yielded Upper Devonian goniatites.
Petrology of the Anorthosite-Gabbro Mass at Kadavur, Madras, India
Authors: Subramaniam A. P. 
Published: May 2009

AbstractA small body of anorthosite with related gabbroic facies from the Archaean of Southern India is described. The mass is inferred to be a funnel shaped phacolithic pluton, emplaced in the crest of a steeply plunging major anticline of metasedimentary quartzite and quartz schists. The marginal rocks of the mass are gabbroic and foliated, while the core is largely made of massive anortho-sites occasionally showing flow structures. The chemistry and petrography of the rocks of this mass suggest their having resulted from differentiation in place of a gabbroic anorthosite intrusion. This occurrence is thought to be a unique example of the Adirondack type of anorthosite, and supports Buddington's hypothesis of evolution of anorthositic rocks from a gabbroic anorthosite magma.
Holothurian Spicules from the Oxford Clay of Redcliff, near Weymouth (Dorset)
Authors: Hodson Frank , Harris Barbara , Lawson Louise 
Published: May 2009

AbstractNine species (eight new) of holothurian spicules are recorded from the Oxford Clay (cordatum zone) of Redcliff, near Weymouth on the Dorset coast. The new species are described and named and the significance of a close association of Rhabdotites and Theelia is discussed. Previous records of holothurian spicules from British strata are reviewed.
Conjugate fold systems in the Moine Thrust Zone in the Lochcarron and Coulin Forest areas of Wester Ross
Authors: Johnson M. R. W. 
Published: May 2009

AbstractThe Moine Thrust Zone in the Lochcarron and Coulin Forest areas contains numerous small scale folds which plunge eastwards. The axial planes of these folds are inclined towards the north or south so that no regional directional translation of the rocks can be postulated from these structures, whose symmetry as a whole is orthorhombic. The folds are considered to have resulted from local lateral extension and concomitant compression of laminated rocks involved in the thrusting.
Facies Boundaries in Pelites at the Middle Grades of Regional Metamorphism
Authors: Francis G. H. 
Published: May 2009

AbstractAn examination of existing definitions of facies and subfacies boundaries in pelitic rocks suggests that some alteration is necessary to emphasize two important reactions:3 Staurolite + 2 Quartz ⇌ Almandine + 5 Al2SiO5 + 3 Water, andMuscovite + Quartz ⇌ Potash feldspar + Al2SiO5 + Water A generalized plot shows possible relations between the curves of these two reactions and the inversion, curves of the aluminosilicates within the P-T field of metamorphism. The curves of further reactions commonly used to define facies and subfacies boundaries have been schematically added to this plot, and trends of metamorphism in various areas are indicated thereon. P-T curves of dehydration reactions such as the above will vary according to the chemical potential of the water vapour in each particular case. Observations suggest, however, that the curves are not very differently placed from one regional metamorphic terrain to another. That is, the rate of escape of volatiles is broadly similar in the metamorphism of many of these terrains.
The Northern Aureole of the Ardara Pluton of County Donegal
Authors: Akaad M. K. 
Published: May 2009

AbstractThe contact aureole on the northern side of the Ardara granitic pluton is made up of an outer part where contact effects are slight, and an inner part in which a broad zone of andalusite hornfelses is succeeded towards the contact by a narrower zone of sillimanite hornfelses. The textures of the hornfelses indicate that several phases of recrystallization, some of them associated with phases of movement, took place during contact metamorphism. Certain phases can be correlated with particular episodes in the evolution of the pluton itself.
Rare Alkali Elements in Trilobites
Authors: McKerrow W. S. , Taylor S. R. , Blackburn Audrey L. , Ahrens L. H. 
Published: May 2009

AbstractLi, Rb, and Cs were determined spectrographically in twenty-eight trilobites, two xiphosurida, four insects, four Crustacea, and six brachiopods. The sediments associated with fifteen trilobites were also analysed. Compared with igneous and sedimentary rocks, the trilobites were characteristically enriched in cesium relative to rubidium and potassium. Thus, the K\Rb ratios were normal, but the Rb\Cs ratios were anomalously low. The evidence is considered to favour the view that cesium has been preferentially concentrated by trilobites during growth. The matrices had Rb\Cs ratios similar to normal sedimentary rocks.
Mesozoic Radiolaria of the Middle East and their Stratigraphical Distribution
Authors: Elliott Graham F. 
Published: May 2009

AbstractRecent work on various Triassic, Jurassic and Cretaceous radio-larian faunas from sections in northern and north-eastern Iraq, all of known stratigraphic horizon, and from elsewhere in the Middle East, confirms the existing view that as absolute indicators of age, without associated evidence, these fossils as commonly preserved are of little use, but that in local and regional problems where they are associated with other evidence they may be of considerable stratigraphical value. The genus Meyenella is not regarded as a useful indicator for the Jurassic.
Metamorphism of Granite Rocks by Olivine Dolerite in Central Australia
Authors: Wilson Allan F. 
Published: May 2009

AbstractA zone of intense metamorphism extends for six feet on both sides of a nearly vertical fifteen feet wide olivine dolerite dyke. Adamellites have been converted in situ to rocks resembling quartz porphyries, and mobilization of cordierite gneiss has been effected. Petrography and chemical analyses show that metamorphism is not purely thermal. Although little actual fixation of doleritic “end liquors” took place in the wall rocks the cause of these remarkable contact effects is ascribed to hydrothermal activity near the “blind end” of the dyke.
Magmatic Intrusions and Lava-sheets in the Raman area of the Nagev (Southern Israel)
Authors: Bentor Yaacow K. 
Published: May 2009

AbstractSouthern Israel is traversed by a series of north-easterly trending anticlines, the largest of which is the Raman anticline. Here a deep erosion-cirque exposes a sedimentary succession from the Cenomanian down to the Triassic, including a series of magmatic rocks of highly alkaline affinities. The forms of these magmatic bodies are described in detail and from their field-relationships with the sediments it is shown that they include a stock, a laccolith, sills, dykes, and a basaltic flow. This igneous activity took place between Lower Triassic and Upper Jurassic times and was perhaps restricted only to the Jurassic. Comparison with the surrounding areas leads to the conclusion that the Raman region was the centre of magmatic activity during this period.
New Evidence on the Correlation of the Lower Carboniferous Reefs at Castleton, North Derbyshire
Authors: Ford Trevor D. 
Published: May 2009

AbstractThere are two alternative hypotheses regarding the relationship of the goniatite-bearing reef limestones to the coral-bearing “massif” limestones. One claims an unconformity between the reefs and bedded limestones, the other a lateral passage from a “massif facies” to “marginal facies”. Surface exposures are such that it is difficult to be convinced of either hypothesis. Details of underground exposures in natural cave systems and associated mine-workings show a clear transition between facies and no trace of unconformity.
The Position of the Falkland Islands in a Reconstruction of Gondwanaland
Authors: Adie Raymond J. 
Published: May 2009

AbstractIn previous reconstructions of Gondwanaland the Falkland Islands have been placed in a position intermediate between the Cape Province and Northern Argentina. In the present paper it is suggested on structural, tectonic, and stratigraphical grounds that it would be preferable to position the Falkland Islands due east of the Eastern Province coast, thus completing the truncated Karroo Basin, the missing part of which has until now been suspected to be concealed beneath the ice-capped Queen Maud Land, Antarctica.
The Development of Lineation in Complex Fold Systems
Authors: Clifford P. , Fleuty M. J. , Ramsay J. G. , Sutton J. , Watson J. 
Published: May 2009

AbstractThe paper refers to a number of areas in which the lineations are related to major folds. It shows that the shapes of individual folds, the interference of neighbouring folds, and the imposition of a second generation of folds all influence the arrangement of linear structures and that lineation maps may only become explicable when the major structure has been determined.
The Petrogenetic Significance of the Contact Relationships of the Donegal Granite in Gweedore and Cloghaneely
Authors: Whitten E. H. T. 
Published: May 2009

AbstractThe “space problem” in north-west Donegal is analysed; structures of country rocks and granite-quartzite contacts, together with marginal granitization, suggest that two space-forming processes operated together. The inter-relationship of these mechanical and chemical processes in Gweedore and Cloghaneely suggests a dual rhythm within Read's (1949) granite series.
On a Volcanic Vent and Associated Monchiquite Intrusions in Monmouthshire
Authors: Eyles V. A. , Blundell C. R. K. 
Published: May 2009

AbstractQuarrying activity adjacent to the well-known intrusion of monchiquite cutting Old Red Sandstone near Usk, in Monmouthshire (originally described by W. S. Boulton, in 1911), shows that the monchiquite proper is associated with an agglomerate-filled vent. Fossiliferous blocks contained within the agglomerate (first recorded by C. R. K. Blundell) show that the volcanic activity took place not earlier than in Lower Carboniferous time; and throw light on the former extension of the Carboniferous Limestone in this area.
A Provisional Reclassification of Granite
Authors: Chayes F. 
Published: May 2009

AbstractThe term “granite” could be usefully reserved for massive or weakly oriented plutonic rocks of colour index less than 20 per cent and quartz content between 20 per cent and 40 per cent by volume. A symbolic classification of rocks meeting these requirements is presented. The various classes are based on the relative proportions of plagioclase and alkali feldspar, and sub-classes based on the ternary dominance ratio quartz-alkali feldsparplagioclase are also proposed. The symbols are simple and easily remembered. A few of the common names now in use are retained for class designations.