bluuebunny/crossref_metadata_2025_split huggingface dataset:
Additions to the non‐marine fauna of the lower coal measures of the North‐Midlands Coalfields
Authors: Eagar R. M. C. 
Published: February 2007

AbstractThe main elements of the non‐marine fauna are reviewed in stratigraphical order in the light of recent revisional work on the Anthracosiidae. Attention is directed towards non‐marine facies and to the lesser known faunas from the upper half of the Lower Coal Measures, from which Carbonicola extenuata and C. proxima spp. nov. are described. Evidence is adduced to suggest that the boundary between the lenisulcata and communis Zones, defined by Wray and Trueman (1934) at the top of the Elland Flags in Yorkshire, should be lowered to the horizon of the Upper Band Coal—Pasture Mine.Detailed work on the Bassy Mine succession (Eagar 1952a) has been extended southward to Huyton, near St. Helens, Pott Shrigley in Cheshire, and to Goyt's Moss in Derbyshire. A summary of results of a special study of shells from about the horizon of the Lower Foot Mine at Goyt's Moss reveals evidence bearing on shell shape and ecological station which is generally in conformity with results from other horizons elsewhere (Eagar 1953b).One new marine or estuarine phase (15 feet above the Six Inch Mine near Bacup) and 11 non‐marine horizons, or records of them, have been found or re‐discovered in Lancashire. New localities and two new non‐marine horizons have been found in Yorkshire. Descriptions of faunas include those of Carbonicola sp. nov. cf. bipennis (Brown), from the horizon of the Lower Foot Mine, assemblages of C. artifex Eagar and variants, and Carbonicola torus Eagar. The species Anthraconaia (?) prisca (Trueman) is now referred to the genus Carbonicola. Anthraconaia sp. nov. has been discovered on a horizon probably below the Upper Band Coal in a boring at Laisterdyke near Bradford. Another new Anthraconaia has been found with Carbonicola torus, C. aff. bipennis and shells resembling Anthracosia from the Modiolaris Zone, near the top of the Elland Flags at Kirkheaton, Huddersfield. Anthraconaia cf. modiolaris (J. de C. Sowerby) has been found in a similar fauna in the basal communis Zone, 60 feet below the Arley Mine at Bolton, Lancashire.
Abnormalities of growth in specimens of gastrioceras from the lower coal measures
Authors: Magraw D. 
Published: February 2007

AbstractCertain abnormalities of growth have recently been seen in specimens of the genus Gastrioceras. These take the form of a distinct groove occurring on the venter, and photographs of three specimens showing the salient features of these grooves are reproduced. Details of the abnormalities are given and their significance discussed.
The late‐glacial climate of North‐West England
Authors: Manley Gordon 
Published: February 2007

AbstractThe combination of geological and botanical evidence with meteorological reasoning leads to the conclusion that in the ninth millenium B.C. small glaciers became re‐established in corries and in the heads of the wetter Lake District valleys, and also in a number of Pennine corries north of Bowland Forest. The meteorological factors giving rise to their distribution and comparative extent are discussed. It is inferred that the amount and distribution of precipitation during this episode resembled that of today. Quantitative estimates are given of the characteristics of the climate during this post‐Alleröd recession, which from the meteorological standpoint appears to be similar to the minor recessions during the post‐Glacial period.
The erosional history of the cliffs around Aberystwyth
Authors: Wood Alan 
Published: February 2007

AbstractThe coastline from Borth to New Quay is described. Three points of general interest emerge. The coastal bevel (hogs back cliffs, fausses falaises) is shown to be the remains of cliffs cut by marine erosion, and degraded by sub‐aerial weathering, at several times in the past. Raised beach platforms occur at different levels, each being backed by degraded cliffs, which merge laterally with the coastal bevel. Later than these, but earlier than the spread of the latest boulder clay in this area by solifluction seawards, are steep “fossil cliffs” cut during apparently two periods of lowered sea‐level. Where the beach platform is cut in solid rocks its outer edge is coincident with the course of one or other of these fossil cliffs.
Nomenclature and diagnostic characters of ignimbrites with reference to Snowdonia
Authors: Beavon R. V. , Fitch F. J. , Rast Nicholas 
Published: February 2007

AbstractThe nomenclature of the welded tufts and ignimbrites is reviewed and it is suggested that the term ignimbrite should include both the welded and the unwelded deposits (sillars) of nuée ardentes. The diagnostic characters of the ignimbrites are examined with special reference to Snowdonia.
Coiled nautiloids from the viséan of Ireland
Authors: Ramsbottom W. H. C. , Moore E. W. J. 
Published: February 2007

AbstractSpecies of the genera Subclymenia, Maccoyoceras (= Epidomatoceras Turner), Stroboceras, Epistroboceras, Phacoceras, Liroceras, Ephippioceras, and Knightoceras are described from on and near Dough Mountain, Co. Leitrim, Ireland, and from Cashel, Co. Fermanagh, Northern Ireland. Faunal associations are noted and the occurrence of species of Liroceras, Rineceras (= Pararineceras Turner), and Vestinautilus are recorded.
The metamorphic history of the Loch Tummel area, central Perthshire, Scotland
Authors: Sturt B. A. , Harris A. L. 
Published: February 2007

AbstractIn the Dalradian rocks of the Loch Tummel area it is possible to establish a series of metamorphic events which are both syntectonic and post‐tectonic in relation to the polyphasal sequence of structures established in the area. Mineral assemblages which have developed during successive phases of metamorphism have been distinguished by their textural relationships, and are assigned to the appropriate metamorphic facies. Comparisons have been made with the metamorphic sequence established by Rast in the Schichallion area.
Superposed folding in the Silurian Rocks of Co. Mayo, Eire
Authors: Dewey J. F. , McManus J. 
Published: February 2007

AbstractSilurian strata of Upper Llandoverian and Wenlockian age, lying in a complex synclinorium south of the Highland Boundary Fault Zone in Co. Mayo, are affected by two main structural episodes. A tight, curving, E–W synclinorium, verging to the south, was developed during the first episode of deformation (F1). Large‐scale cross‐buckling, followed by variable flattening in the axial‐planar schistosity, was responsible for a considerable plunge variation of F1 folds. A mechanism is described whereby primary downward‐facing minor folds may be produced in an upward‐facing major structure. Three slides, of considerable magnitude, are co‐planar with the schistosity. During the second episode of deformation (F2) a slip‐cleavage, dipping steeply to the NNE, was superimposed upon the F1 synclinorium. It is deduced, partly from an analysis of the geometry of F2 minor structures, that the arcuate curvature of the F1 synclinorium is pre‐F2 and was developed during the F1 deformation as a response to the presence of an early or pre‐F1 granite pluton. F2 folds show a great variability in plunge and facing direction, depending upon their position in the F1 major structure.
Iron enrichment and pyroxene fractionation in tholeiites
Authors: Muir I. D. , Tilley C. E. 
Published: February 2007

AbstractDifferentiation in tholeiite magma, particularly iron enrichment and silica variation, as traced in lava successions and dolerite‐granophyre suites, is discussed in the light of analytical data on phenocryst and groundmass pyroxenes and their fractionation. Broadly two trends may be distinguished: (1) an intratelluric equilibrium trend ending in a hedenbergitic pyroxene phase fayalite, such as is exhibited by the Tasmanian Red Hill dolerite‐granophyre suite, and (2) a quench trend characteristic of the subcalcic augite groundmass sequence of the volcanic suites as exemplified in the Hawaiian tholeiite series (e.g. Kilauea). This trend may in more siliceous differentiates be extended to close with assemblages carrying a ferropigeonite phase.
The geology of the Clynnog‐fawr district and Gurn Ddu hills of Northeast Lleyn
Authors: Tremlett W. E. 
Published: February 2007

AbstractThis area of Wales is a westerly continuation of the northern limb of the Snowdon syncline and stretches from the Pre‐Cambrian volcanic series in the north to just above the abbreviated Snowdon Volcanic Series in the south. Large parts of the intervening area consist of Caledonian intrusive rocks, but the middle part of the sedimentary succession has yielded scattered graptolites, most and probably all, of Llanvirn age. The exposed volcanic rocks are largely of ignimbrite character while the Caledonian intrusions are of four types (for which chemical analyses are given). The sequence of these four rock‐types and of the structural events of the district is considered.
The geology of the Chwilog area of Southeastern Lleyn (Caernarvonshire)
Authors: Tremlett W. E. 
Published: February 2007

AbstractDue partly to folding but mainly to faulting, the Caradocian volcanic rocks outcrop in three districts within this area, and this repetition of outcrop reveals the variation shown by this dominantly rhyolitic volcanic series. A thick lower group of submarine bedded tuffs, thinning and fading out northwestwards, is followed unconformably by subaerial andesite and rhyolitic rocks in the north, but these volcanic rocks are absent or represented by bedded tuffs in the southern districts. The overlying sediments are generally poorly exposed but have yielded Upper Longvillian fossils from a number of localities. Caledonian intrusions are neither so numerous nor so varied as in northern Lleyn, but include granodioriteporphyries and felsites. Explosion breccias are present at the margins of some of the felsites. Nine chemical analyses indicate the variety of composition in the volcanic series while two analyses of Caledonian felsites are also supplied.
Geochemistry of an ordovician basalt‐trachybasalt‐subalkaline/peralkaline rhyolite association from the Lleyn Peninsula, North Wales, U.K
Authors: Leat P. T. , Thorpe R. S. 
Published: February 2007

AbstractThe Caradoc volcanic rocks of the Lleyn Peninsula represent a major episode of rhyolite‐dominated eruption (total volume up to 560 km3) within the Southern British Caledonides. New geochemical data reveal the original chemical characteristics of the basic, intermediate, and acid lavas. The basalts are interpreted as having predominantly within‐plate character and are associated with intermediate lavas (trachybasalts) and high‐Zr, originally peralkaline, trachytes, and rhyolites. A low‐Zr, originally high‐K, subalkalic group of rhyolites, and a basalt with transitional island arc tholeiite‐MORB characteristics are unrelated to these lavas. The volcanic rocks are interpreted to have been erupted onto a complex, rapidly evolving, active continental margin dominated by crustal tension.
Eocene sheetflood systems and transitional fan‐deltas, Southern Pyrenees, Spain
Authors: van der Meulen Sjoerd 
Published: February 2007

AbstractThe Eocene Monllobat and Castigaleu Formations in the Southern Pyrenees consist of continental and shallow marine deposits respectively. The Monllobat Formation contains conglomerate sheets with sandstone tails, symmetrical channel fills with wings and various types of lobes, accreted laterally in channels as well as by progradation. These deposits are intercalated in large amounts of flat‐bedded silt and mudstone with mottling and caliche.The high energy alluvial flow, which deposited these sediments, was initially at right angles to the axis of the elongated basin, becoming near parallel to the axis distally. The deposits are less gravelly distally. Upstream wide, gravelly braidplains were developed. Gravel lobes and muddy sheetfloods prograded over the distal floodplain. Meandering rivers were restricted to a marginal position in the sheetflood environment.The Castigaleu Formation consists of mudstone with intercalations of sandstone. Lobes of conglomerate and sandstone dominate the contact zone with the Monllobat Formation. Flat sandstone layers with tabular cross beds and parallel lamination and massive sandstone beds are distributed throughout the other parts.The lobes were formed at the coastline during high energy inflow in the marine basin. Flow deceleration caused the deposition of the coarsest load at this site, building a wedge with an inclined front during major aggradation and progradation. The other deposition types originated during hyperpycnal inflow in a marine environment. Massive sandstones originated partly because of bioturbation. Reworking by physical marine processes did not occur. Synsedimentary tectonics determined the type of sedimentation at times.
The Valley and Ridge Province of eastern Pennsylvania—stratigraphic and sedimentologic contributions and problems
Authors: Epstein Jack B. 
Published: February 2007

AbstractMany contributions that have led to a better understanding of Appalachian geology have resulted directly from work in the folded Appalachian Mountain and Great Valley sections of the Valley and Ridge physiographic province of eastern Pennsylvania. Disagreements have been common since H.D. Rogers first described the geology of the area in 1858. Many differing opinions still exist regarding the stratigraphy, structural geology, geomorphology, and glacial geology.The rocks in the area, which range from Middle Ordovician to Late Devonian in age, are more than 25000 feet (7620 m) thick. This diversified group of sedimentary rocks was deposited in many different environments, ranging from deep sea, through neritic and tidal, to alluvial. In general, the Middle Ordovician through Lower Devonian strata are a sedimentary cycle related to the waxing and waning of Taconic tectonism. The sequence began with a greywacke‐argillite suite (Martinsburg Formation) representing synorogenic basin deepening. This was followed by basin filling and pro‐gradation of a sandstone‐shale clastic wedge (Shawangunk Formation and Bloomsburg Red Beds) derived from the erosion of the mountains that were uplifted during the Taconic orogeny. The sequence ended with deposition of many thin units of carbonate, sandstone, and shale on a shelf marginal to a land area of low relief. Another tectonic‐sedimentary cycle, related to the Acadian orogeny, began with deposition of Middle Devonian rocks. Deep‐water shales (Marcellus Shale) preceded shoaling (Mahantango Formation) and turbidite sedimentation (Trimmers Rock Formation) followed by another molasse (Catskill Formation).
Carboniferous (Dinantian and Silesian) and Permo‐Triassic rocks in south County Wexford, Ireland
Authors: Clayton G. , Sevastopulo G. D. , Sleeman A. G. 
Published: February 2007

AbstractBoreholes drilled in the Wexford Outlier have proved Permo‐Trias conglomerate and red beds (Killag Formation), Westphalian D sandstone and mudrock. including at least one thin coal (Richfield Formation), and probable Namurian mudrock (Park Formation). The Killag Formation rests on the Westphalian, the Namurian, and on Dinantian (probably Asbian) limestone in different boreholes. The Westphalian contains horizons with bivalves, conchostracans, and plants and has yielded miospore assemblages which, in addition to indigenous taxa, contain reworked material of three different ages: Devonian or early Carboniferous; late Viséan or early Namurian; and Westphalian A. The western end of the Welsh massif of previous palaeogeographical reconstructions was of very low relief during the Silesian and probably was more often a site of deposition than of erosion.
An unusual crinoid columnal from salthill quarry, Clitheroe, Lancashire
Authors: Donovan S. K. 
Published: February 2007

AbstractAn unusual crinoid pluricolumnal from the Lower Carboniferous of Salthill Quarry, Clitheroe, Lancashire, has a tetrastellate lumen. This may be derived from either a cupressocrinitid or a gasterocomid, two families of cladid inadunate which have previously only been reported from the Devonian. Large inadunate cups are relatively rare at Salthill but columnals are varied and numerous, so it is not surprising that the first indications of such a crinoid at this locality should be given by dissociated ossicles. However, it is also possible that this columnal represents an aberrant individual of a species with an axial canal that is usually pentastellate.
Rb‐Sr whole‐rock isochron studies of the Barnesmore and Fanad plutons, Donegal, Ireland
Authors: O'Connor P. J. , Long C. B. , Evans J. A. 
Published: February 2007

AbstractResults of Rb‐Sr whole‐rock isochron studies of the Barnesmore and Fanad plutons of Co. Donegal are presented. The Barnesmore pluton yields an age of 397 ± 7 My and initial 87Sr/86Sr ratio of 0·7063 ± 0·0005 (MSWD 10·2) while the Fanad pluton yields an age of 402 ± 10 My and initial 87Sr/86Sr ratio of 0·7050 ± 0·0001 (MSWD 1·6).These studies supplement recent Rb‐Sr dating of the Donegal granitoid batholith by Halliday et al. (1980) and O'Connor et al. (1982), and confirm that the entire suite was emplaced during a short interval spanning mid‐Silurian to earliest Devonian time. The relatively low and restricted range of initial Sr isotope ratios suggests small, but significant, differences in the composition of the source region of these ‘Caldedonian I‐type’ magmas.The Rb‐Sr data indicate that contamination processes have not played a significant role in the petrogenesis of the Fanad rocks and their intermediate character and high Sr content are considered primary features of the parent dioritic magma. At Barnesmore, late stage devolatilization of evolved granitic magmas has resulted in the development of desilicated zones within the pluton: the granite of such zones may exhibit elevated 87Sr/86Sr ratios.
Macrofloral biostratigraphy of the Newent Coalfield, Gloucestershire
Authors: Cleal C. J. 
Published: February 2007

AbstractBoreholes recently drilled by the British Geological Survey provide the first extensive collection of fossil plants from the Newent Coalfield, Gloucestershire. They belong to the Lobatopteris vestita Biozone, indicating a late Westphalian D age. The Newent sequence is thus homotaxial with part of the Forest of Dean Coalfield, and supports the view of Wills (1956) that there was a ‘strait’ extending across St George's Land during the late Westphalian.
Gravity anomalies associated with the Cefn‐y‐Fedw Sandstone Group, northeast Wales, and their geological significance
Authors: Cornwall J. D. 
Published: February 2007

AbstractRegional and detailed gravity surveys over Carboniferous rocks in northeast Wales have revealed an elongated Bouguer anomaly low over part of the outcrop of the Cefn‐y‐Fedw Sandstone Group. The anomaly has a pronounced gradient over the boundary of these sediments with the limestones of the underlying Viséan Series, but downdip, to the east, the anomaly merges with the general decrease of Bouguer anomaly values. The anomaly can be explained if the thickness of the lower density Cefn‐y‐Fedw Sandstone Group increases abruptly along the margin of the outcrop of these rocks. Various explanations for this are considered including faulting, a syncline. and channel‐like deposits. The interpretation is further complicated by the presence of sandstones with densities varying between 2·2 Mg m−1 and 2·6 Mg m−3Although a full explanation is not possible without further evidence, the existence of the Bouguer anomaly low necessitates a review of the nature of the Cefn‐y‐Fedw Sandstone Group.
Late Pan‐African magmatism and crustal development in northeastern Egypt
Authors: Abdel‐Rahman Abdel‐Fattah M. , Martin Robert F. 
Published: February 2007

AbstractThe voluminous Pan‐African calc‐alkaline granitic suite of the Ras Gharib crustal segment in northeastern Eygpt provides a typical example of orogenic magmatism. The 552 ± 7 Ma‐old granodiorite–adamellite and leucogranite suite is compositionally broad (58 to 77 wt.% SiO2) and exhibits calc‐alkaline geochemical trends and trace‐element characteristics typical of the volcanic‐arc granites. The rocks contain oligoclase, albite, K‐feldspar, calcic amphibole, biotite, titanite, zircon, and magnetite. The suite exhibits typical features characteristic of I‐type granites.We contend that the magma was formed by partial melting of a modified oceanic crust at an active continental margin during the late stage of the Pan‐African orogeny. The process may have involved assimilation of Early Pan‐African dioritic country rocks. The more felsic units were produced by progressive fractionation of that magma. The petrological–geochemical evidence suggest that the Pan‐African crust in northeastern Egypt did not develop in an extensional tectonic regime, as proposed recently.
The Moel‐y‐Golfa Andesite: An Ordovician (Caradoc) intrusion into unconsolidated conglomeratic sediments, Breidden Hills Inlier, Welsh borderland
Authors: Dixon R. J. 
Published: February 2007

AbstractThe Moel‐y‐Golfa Andesite is a discordant intrusive body of porphyritic pyroxene andesite, 1 km across and at least 200 m thick. Textural variation defines a central facies and a marginal facies, the latter displaying well‐formed lobes, tubes, and pillows. The vertically stacked lobes, brecciated tubes, and elongate pillows of andesite intrude and locally enclose enclaves of altered host sediment and are cut by steeply dipping slide scars. The host sediments are locally strongly silicified and cut by numerous, anastomosed vertical and subvertical fissures. Fissures are filled by disrupted host sediment and fragments of brecciated andesite. The formation and filling of each fissure system was probably concomitant with the brecciation of an intrusive magma lobe. The complex relationship of igneous and sedimentary material indicates that the Moel‐y‐Golfa Andesite was emplaced into the host sediments whilst they were unconsolidated or only partly lithified.
A sedimentological study of diamondiferous Quaternary sediments in Southern Shandong, China
Authors: Dobbs P. N. , Yaping Guo , Siyi Hu , Jianrong Lin , Lianquan Luo , Jinsong Zang , Xiongying Zhao , Harris J. W. 
Published: February 2007

AbstractA sedimentological study of the lower Quaternary sediments in southern Shandong Province suggests that they were derived from a northern highland area of Archaean gneiss and Palaeozoic sediments. Diamond‐bearing kimberlites, intruded during the Ordovician, occur in the highland area and are a possible source of diamonds found in the Quaternary sediments. A warm and humid climate prevailed at the beginning of the Quaternary and braided rivers carried gravel and sand southeast towards the Yellow Sea. Cooler and drier conditions in Q2 times reconcentrated diamonds from the underlying Q1 gravels. Post‐Q2 faulting deflected the drainage to the south and subsequent erosion left only small remnants of diamondiferous Q2 gravel. A study of diamond shape characteristics suggests that the diamonds in the Quaternary sediments were derived from the known kimberlites to the north, although the possibility of undiscovered kimberlites occurring beneath the Quaternary sediments cannot be ruled out.