bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Outline of the Geomorphology of Murrisk and North-West Galway
Authors: Dewey J. F. , McKerrow W. S. 
Published: May 2009

AbstractThe denudation chronology of the mountainous district of south-west Mayo and north-west Galway is closely linked with drainage superimposition from a deformed Carboniferous cover. Small outcrops of basal Viséan sandstones and conglomerates, lying on bevelled summits and wide bevelled tablelands demonstrate unequivocally that the west Connaught summit level corresponds to the base of the Carboniferous. Uplift, to produce a pre-glacial divide, is believed to have occurred in Mid-Tertiary times. Upon the uplifted, faulted, and warped Carboniferous cover a consequent drainage was developed. Superimposition on to the Caledonian basement followed and during the Pleistocene considerable glacial modifications of the pre-glacial drainage pattern took place.
Evolution of Drag Folds
Authors: Ramberg Hans 
Published: May 2009

AbstractTheory and experiments show that a component of compressive strain parallel to layering is necessary to develop drag folds. The component of shear strain needed for the monoclinic symmetry of such folds is not sufficient to form the wavy pattern. Based upon fluid dynamic theory and experiments with layered rubber slabs it is suggested that drag folds on flanks of major folds generally evolve as follows: Layer-parallel compression of more or less straight layered rocks causes some layers to shorten essentially by more or less uniform compressive strain and thickening (thick and not-so-competent layers), other layers to shorten essentially by buckling (thin and most component layers). In the course of time, however, the rate of buckling of the thick layers becomes significant relative to the rate of arc-shortening, and the thin layers with the early formed short buckles are forced to mimic the larger folds of the thick layers more or less passively. In this process the early formed short buckles become tilted and assume the typical drag-fold shape.
The Downtonian and Dittonian Facies of the Welsh Borderland
Authors: Allen J. R. L. , Tarlo L. B. 
Published: May 2009

AbstractThe succession of Lower Old Red Sandstone rocks found in the Welsh Borderland, is reinterpreted to reveal a shifting pattern of facies of far greater complexity than was hitherto realized. The sequence of vertebrate faunas is examined in conjunction with the sediments, and in this way a fuller account is given of the conditions of life of these early vertebrates, than was previously possible. The boundary between the Downtonian and Dittonian Stages is revised to coincide with the major palaeontological break in the region, and this is shown to approximate to a major lithological break, which is here accepted as the division between the local rock units known as the Downton and Ditton Series.
Agglutinate in North Jan Mayen
Authors: Hawkins T. R. W. , Roberts B. 
Published: May 2009

AbstractIn North Jan Mayen agglutinate is recognized as an important and widespread pyroclastic deposit of recent parasitic activity associated with the Beerenberg volcano. Lips of agglutinate along fissures, areas up to one square kilometre composed entirely of agglutinate, and other smaller morphological features are described. It is proposed to term the more widespread areas of agglutinate, “agglutinate fields,”, owing to their superficial resemblance to aa lava fields. Two varieties of agglutinate, one composed mainly of pancakes and bombs and the other of driblets of ankaramitic basaltic material are described, and conclusions given on their significance and formation.
A Reconsideration of Certain Aspects of the Rangwa and Ruri Carbonatite Complexes in Western Kenya
Authors: McCall G. J. H. 
Published: May 2009

AbstractDykes with melilite occur in the area peripheral to the Rangwa complex. A flow-lineated alvikite dyke situated in the area just outside the North Ruri complex contains calcitic pseudomorphs of phenocrysts, and it is suggested that the majority of these are after melilite. The significance of the observed restriction of melilitic dykes to the peripheral area of the complexes is considered in the light of the recognition of a gradational progression from kimberlite-alnöite dykes to beforsite and alvikite dykes at Alnö island and its environs in Sweden. The possibility that cauldron subsidence is involved in some of the Kenya complexes is considered.
Proterozoic Palaeocurrent directions in the Kimberley Region, Northwestern Australia
Authors: Gellatly D. C. , Derrick G. M. , Plumb K. A. 
Published: May 2009

SummaryPalaeocurrent directions from cross-beds in the Proterozoic Kimberley Basin sediments, north-western Australia indicate sediment transport predominantly from the north-east in the lower part of the succession, and from the north-west in the middle and upper parts. Most of the sediment was probably derived from the north and only a little from the adjacent exposed areas of older Pre-Cambrian rocks to the south. The suggested northerly source of the sediment is consistent with a probable former position of Western Australia close to Peninsular India and to Burma.
Bathymetric distributions of Calcarea and Hexactinellida in the present and the past
Authors: Reid R. E. H. 
Published: May 2009

SUMMARYCalcarea and Hexactinellida are now characteristic of different depth zones, and have shown comparable bathymetric zonation since the Carboniferous period. This paper reviews and discusses relevant evidence from modern and fossil sponge faunas, together with some problems involved in the use of the modern data for the assessment of past depths. The most important independent evidence is provided by calcareous algae and herma-typic Scleractinia.
The Raised Beaches of the North Coast of Sutherland, Scotland
Authors: King Cuchlaine A. M. , Wheeler P. T. 
Published: May 2009

AbstractMeasurements were made of features formed in relation to former sea-levels along the north coast of Sutherland between Melvich and Durness. The results suggest that four raised-levels can be identified. The uppermost, which is at a greater elevation on the east, is related to glacial and fluvio-glacial deposits, which indicate its formation in close proximity to glaciers. This level has been correlated with the “100 ft.” beach. The next level also shows slight tilting up to the east and seems to correspond with the “50 ft.” level elsewhere in Scotland. The two lowest levels are horizontal, and can be correlated with the “25 ft.” and “15 ft.” levels respectively.
Pumice Eruption in the Area of the South Sandwich Islands
Authors: Gass I. G. , Harris P. G. , Holdgate M. W. 
Published: May 2009

AbstractAn extensive pumice raft was encountered by H.M.S. Protector in the area of the South Sandwich Islands on the 14th March, 1962. Evidence is presented which suggests that this material was ejected on the 5th March, 1962, from a submarine eruptive centre 35 miles to the north-west of the existing islands but on the axis of the South Sandwich Arc.
A New Species of Pseudoclimacograptus from the Ordovician of Marathon, Texas
Authors: Clarkson Cynthia M. 
Published: May 2009

AbstractSpecimens of Pseudoclimacograptus marathonensis sp. nov., preserved in relief, from the Ordovician of Marathon, Texas, are described. An account of a series of sections of the proximal end is also given. The material is compared with the compressed syntypes and other specimens of Amplexograptus Confertus (Lapworth), with which the new species had been confused.
Lateral Cryptic Variation in the Great Dyke of Rhodesia
Authors: Hughes Charles James 
Published: May 2009

SummaryA lateral cryptic variation is recognized in layered ultramafic rocks of the Hartley Complex, the largest of the four lopoliths that constitute the Great Dyke. Over a lateral distance of some 120 km, the En content of orthopyroxene from thick, continuous bronzitite layers is up to 6% less at the southern extremity of the Complex than in the central area. This is interpreted to be a result of more rapidly falling temperatures in a thinner body of basic magma that gave rise to a condensed sequence in marginal areas of the lopolith compared to the central area.Following a well-marked period of addition of parental basic magma which appears to have had the incidental effect of linking up the four lopoliths, this compositional relationship in composition is reversed, i.e. the orthopyroxene from the base of an upper bronzitite layer of the southern marginal area of the Hartley Complex is more magnesian than that from the equivalent level in the central area. This is interpreted to arise from the proportion of fresh added magma to previously emplaced and partly crystallized magma being relatively greater in the marginal area than in the central area of the lopolith.
A new Campanile from the Palaeocene of Western Nigeria
Authors: Adegoke O. S. , Dessauvagie T. F. J. 
Published: May 2009

SummaryCampanile nigeriense sp. nov. is described and figured from the Palaeocene Ewekoro Formation of Western Nigeria. Its juvenile whorls characteristically have four smooth and broad spiral ribs while adult whorls are completely smooth. Vertical ornamentations are lacking. This second record of Campanile from West African Palaeocene strata suggests that the genus may be a stratigraphically useful index fossil in West Africa.
Early joint formation in sediments
Authors: Cook A. C. , Johnson K. R. 
Published: May 2009

SummaryJointing in some ‘ironstone’ intraclasts in a sandstone from the Sydney Basin, New South Wales shows that the joints were developed prior to contemporaneous erosion. A number of other features observed in the Sydney Basin sequence support this conclusion and suggest that an anisotropic horizontal stress field developed in the sediments very soon after their deposition.
Some species of Bryograptus and Pseudobryograptus from Northwest Europe
Authors: Bulman O. M. B. 
Published: May 2009

SummaryThe genotype of Bryograptus, B. kjerulfi Lapworth, is figured and redescribed together with B. ramosus Brøgger, B. bröggeri Monsen and Pseudobryograptus cumbrensis (Elles).
The Petrography and Origin of Deposits filling Solution Pipes in the Chalk near South Mimms, Hertfordshire
Authors: Thorez J. , Bullock P. , Catt J. A. , Weir A. H. 
Published: May 2009

SummaryPipes and other solution cavities in the Upper Chalk near South Mimms contain deposits unlike those found in similar situations elsewhere in Great Britain. The cavities were formed near the sub-Palaeogene surface, and most of the deposits in them were derived from the basal Palaeogene beds (Thanetian and Sparnacian). A dark brown and very porous clay, which lines many of the pipes, is composed partly of the insoluble residue from the Chalk and partly of clay eluviated from the Palaeogene deposits. The clay was deposited from percolating water in spaces formed by dissolution of chalk at the margins of the pipes.
Size-graded layering in the Imilik gabbro, East Greenland
Authors: Brown P. E. , Farmer D. G. 
Published: May 2009

SummaryRhythmic layering in which the layers grade from coarse base to finer top is described in a plagioclase—pyroxene—olivine gabbro. The medium sizes of the various cumulus minerals at each level have significantly different settling velocities. Variation in the proportions of the cumulus minerals accompanies the size grading. It is shown that these characteristics can reasonably be accounted for if hydrodynamic factors exerted the main control, over-riding any chemical effects.
The intrusive form of some basalt dykes showing flow lineation
Authors: Roberts John L. , Sanderson David J. 
Published: May 2009

SummaryThe dilational intrusion is described of some basalt dykes of Tertiary age into the Easdale Slates at Easdale, Argyllshire. The intrusive form of the dykes results from the walls of irregular fractures, guided by pre-existing planes of weakness, moving apart under magma pressure. The propagation of the fractures is discussed in relation to the external stress field controlling the intrusion of the dykes and the direction of opening of the fractures considered in relation to the magma pressure and the external stress field. The flow lineations developed at the margins of the dykes are discussed in terms of their mode of origin. Although the attitude of these lineations varies with the intrusive form of the dykes, the overall direction of flow of the magma was upwards to the north of northwest.
Ocellar Hybrids from the Tyrone Igneous Series, Ireland
Authors: Angus N. S. 
Published: May 2009

AbstractOcellar hybrid rocks, formed by metasomatic transformation of basalt xenoliths engulfed in granitic magma, are characterized by numerous small, oval quartz porphyroblasts, each sheathed with narrow rims of amphibole. The progressive development of these quartz ocelli, together with the general texture of the ocellar hybrid, is traced through a number of intermediate hybrid types. In some instances, the ocellar hybrid displays an intrusive relationship toward basalt and is thought to have undergone a certain amount of metasomatic mobilization.
Vermiform Burrows and Rate of Sedimentation in the Lower Greensand
Authors: Middlemiss F. A. 
Published: May 2009

AbstractVermiform burrows, which are common in the Lower Greensand, can be used to estimate the relative rate of sedimentation, repeated penetration by burrowing organisms being taken as indicating slow deposition, a single undisturbed penetration as indicating rapid deposition. Application of this criterion is illustrated by reference to the Ferruginous Sands of the Isle of Wight.
Potassium–Argon Age Studies in Scotland
Authors: Miller J. A. , Brown P. E. 
Published: May 2009

AbstractNew potassium-argon age determinations are presented for rocks ranging in age from Lewisian to Tertiary. A late-Caledonian metamorphic event at about 422 million years is very important in the Highlands and the relationship of this to previous metamorphisms is discussed. Newer Granite emplacement took place about 400 million years ago and the Moine thrust movement also took place at about this date. Lower Carboniferous basalts yield, by whole rock methods, ages compatible with the time scales of Kulp (1960) and Holmes (1959). Volcanic activity in Mull is confirmed as Palaeocene or Eocene in age.
A Revision of Retepora nodulosa Phillips, 1836
Authors: Tavener-Smith R. 
Published: May 2009

AbstractA fenestrate bryozoan species recently collected from the Visean of County Fermanagh, Ireland, appears to correspond in all respects with Retepora nodulosa Phillips, from a similar horizon in Yorkshire. The last-named form was never satisfactorily defined or illustrated, the original type material is lost, and after being neglected for many years the name was declared a nomen dumium by Miller (1961). It is now recognized that, because of the presence of biserial carinal nodes, the species properly belongs in the genus Minilya, Crockford, 1944. It is here redescribed on the basis of a neotype from Fermanagh.
Axial-trace-fractures and Deformed Concretionary Rods in South Pembrokeshire
Authors: Hancock P. L. 
Published: May 2009

AbstractAxial-trace-fractures are defined as joint or fracture cleavage surfaces which intersect bedding surfaces parallel to adjacent fold axes, and which meet stratigraphically higher bedding surfaces at acute angles closing towards adjacent anticlinal hinges. In the Upper Palaeozoic rocks of South Pembrokeshire these fractures are developed equally on fold limbs, in regions of low dip, and around fold hinges. Characteristically they are interrupted at bedding surfaces and vary in frequency with lithology. The value of the angle they subtend with bedding surfaces varies with lithology and dip.Calcareous concretionary rods, thought to have been originally normal to depositional surfaces, are now orientated parallel to axial-trace-fractures and at right angles to fold axes.The axial-trace-fractures of South Pembrokeshire are considered to have been formed immediately before or at the start of the Armorican folding, and then to have been rotated and sheared during the folding.Other joints associated with axial-trace-fractures are described and briefly discussed.
Structural Study of the Contorted Drift and Disturbed Chalk at Weybourne, North Norfolk.
Authors: Banham P. H. , Ranson C. E. 
Published: May 2009

AbstractA structural analysis of the cliffs and one pit section in Pleistocene deposits at Weybourne has shown one major phase of ice movement only. Ice moving from approximately 210 degrees caused the disturbance of the upper part of the Chalk (together with the overlying Weybourne Crag) and the deformation and deposition of a chalky-boulder-clay, thought to be equivalent to the Lowestoft till.
The West Limb of the Loch Awe Syncline and the Associated Cleavage Fan
Authors: Borradaile Graham John 
Published: May 2009

SummaryThe Loch Awe Syncline (Bailey, 1913), affecting the Middle and Upper Iltay Dalradian Successions of Argyllshire, is recognised as an F1 structure. The present work shows that the west limb is arched over a pre-O.R.S., late Caledonian monoform responsible for the fan of first cleavage over the area investigated. Reflecting the style of the earlier Ben Lui-Tarbert Monoform (Roberts & Treagus, 1964), the newly described Kilmelford–Turnalt Monoform adds to the symmetry of the Iltay Nappe Complex. “Mushroom” Structure (Rast, 1963).
The Influence of Geological Factors on the Strength of Coal Measure Rocks
Authors: Price Neville J. 
Published: May 2009

AbstractA study has been made in the laboratory of the strength of a “suite” of coal measure rocks in uniaxial and triaxial compression. From the data obtained it is demonstrated that the compressive strengths are profoundly influenced by the composition, porosity and degree of compaction of the rocks. It is indicated that these factors also influence the tensile and cohesive strengths.
The elevation of the Lower Greensand ridge, south-east England
Authors: Chorley R. J. 
Published: May 2009

SUMMARYThe influence of three classes of factors—geological structure, lithologic composition and spatial control over erosion—are examined by trend-surface analysis, followed by stepwise regression, in order to determine their relative importance in explaining the variation observed in the elevation of the Lower Greensand ridge of south-east England. It is concluded that structural controls are dominant, lithological controls very subordinate and the spatial control of very marginal significance.
Correlation problems of metamorphosed Pre-Cambrian rocks in Wales and S.E. Ireland
Authors: Baker J. W. 
Published: May 2009

SUMMARYThe lithological and structural characteristics of the metamorphosed Pre-Cambrian rocks of Wales and Leinster are reviewed, and the Dutch Gin Schists are not accepted as a stratigraphical unit. The Bray Series, Cullenstown Group, Ballycogly Group and Bedded Succession of North Wales are regarded as parts of a single Monian System which accumulated in a Caledonoid trough and was involved in a late Pre-Cambrian orogeny. The latter also affected the pre-Monian basement, parts of which (possibly unrelated to one another) are seen in the gneisses of Co. Wexford (Rosslare Complex), Lleyn and Anglesey.
Detrital Portland chert and limestone in the Upper Purbeck Beds at Friar Waddon, Dorset
Authors: West Ian M. , Hooper Malcolm J. 
Published: May 2009

SUMMARYPebbles of derived Portland chert and limestone have been found in the Upper Purbeck Beds at Friar Waddon, Dorset. The Unio Bed at this locality is of unusual lithology with derived phosphatic fossils and with fish teeth. The presence of this chert in the Upper Purbeck Beds and its apparent absence in Lower Purbeck pebble beds suggests that a major phase of silicification in the Portland Stone took place at about Middle Purbeck times. Furthermore, erosion of the Portland Beds occurred in the Weymouth region, probably on the crest of the Weymouth anticline, during Upper Purbeck times.
Fluviatile Deposits in Namurian rocks of Central Scotland
Authors: Alfred Read William 
Published: May 2009

SUMMARYIn the Clackmannan Syncline and the north-eastern part of the Central Coalfield the Passage Group succession between No. 2 Marine Band (?Arnsbergian, E2) and the Netherwood Coal (Kinderscoutian, R1) represents a period when meandering rivers with gently sloping floodplains replaced deltas. The succession consists of upward-fining cycles in which crossstratified sandstones with disconformable bases grade up into unstratified rooty siltstones and mudstones. The thicker sandstones probably represent meander belt deposits, the thinner sandstones the infillings of single channels and the mudstones and siltstones overbank (floodbasin) deposits. Desiccation cracks and partial oxidation phenomena indicate periods of low water table.
A simple alkalinity ratio and its application to questions of non-orogenic granite genesis
Authors: Wright J.B. 
Published: May 2009

SUMMARYCommonly used variation diagrams do not convincingly distinguish strongly alkaline, alkaline and calc-alkaline rocks over the full range of silica contents, especially for more acid varieties. In particular, the Rittmann Suite Index, a, becomes invalid once SiO2 exceeds about 70%.
A Structural Study of the Southern End of the French Jura
Authors: Lindström Maurits 
Published: May 2009

AbstractIn the Chambéry region, Jura folds with a north-north-west trend meet the boundary of the Subalpine zone, which strikes north-north-east. The two fold trends were probably not formed at exactly the same time. Minor folding, thrusting on steep planes, wrench-faulting, formation of sub-horizontal stylolites, and opening of filled joints all took place during a succession of tectonic events with maximum compression at about east-west, after the aforementioned fold-trends had been formed. The evidence considered in this study seems incompatible with hypotheses of deformation by gravitational gliding.
The Provenance and Emplacement of Upper Arenigian Turbidites in Co. Mayo, Eire.
Authors: Dewey John Frederick 
Published: May 2009

AbstractFive thousand feet of Upper Arenig turbidites are described with reference to their provenance and mechanism of emplacement. The turbidites were emplaced in a gently curving E.–W. trough whose width was approximately 20 miles and minimum length 50 miles. Axial and lateral derivation are recognized and it is suggested that entirely different mechanisms were responsible for the emplacement of each type.
A Note on the Composition of some Natural Acid Glasses
Authors: Carmichael Ian 
Published: May 2009

AbstractPitchstones and obsidians from Arran, Eigg, and Iceland, are shown to have small but distinct differences in their major-and trace-element composition, and it is concluded that acid magma in the British Tertiary as represented by the pitchstones from Arran and Eigg maybe more variable in composition than that of the Icelandic subprovince. Fourteen new analyses are represented.
The Madai-Baturong Limestone Member of the Chert-Spilite Formation, North Borneo
Authors: Adams C. G. , Kirk H. J. C. 
Published: May 2009

AbstractPelagic Foraminifera found in the marginal parts of the limestone at Mount Madai in south-eastern North Borneo indicate that it is of Upper Cretaceous age. Much of the limestone at Mount Madai and Mount Baturong does, however, contain algae and other microfossils characteristic of Lower Cretaceous rocks in other parts of the world.The limestone is provisionally classified as the Madai–Baturong Limestone Member of the Chert-Spilite Formation. Revision of the stratigraphy has clarified the regional structure, and it is postulated that the Chert-Spilite Formation has been uplifted against Neogene sediments along a major zone of thrust faulting.