bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some late Pleistocene involutions at Dalton‐in‐Furness, northern England
Authors: Johnson R. H. 
Published: July 2010

AbstractInvolutions are reported for the first time from northwest England. They occur in ‘head’ deposits of reworked mudstone, shale, sandstone and breccia soliflucted over glacio‐fluvial sands and gravels in the Poaka Beck valley. The involutions were developed in the late Devensian period and most present a strongly festooned cross‐section. Excavation of these features showed that the regular form was a result of chance sectioning and that the cryoturbate structures were a cellular or pocket type of feature. Frost heave, ice segregation and a reversed density stratification all probably contributed to the development of the involutions, but an important factor was the ground water hydrology which gave especially favourable conditions for strong cryergic activity at this site.
The geology of Howth and Ireland's Eye, Co. Dublin
Authors: Van Lunsen H. A. , Max M. D. 
Published: July 2010

AbstractThe Cambrian sediments in Howth and Ireland's Eye to the northeast of Dublin have been mapped and the submarine deltaic Censure Group and the overlying Nose of Howth Group, which consists of interbedded turbidites and olistostromes, have been distinguished. Large scale sedimentary disruption has accompanied detachment of quartzitic sandstone beds in the Censure Group, where the bases of detached blocks have slump features while their tops generally do not. This contrasts with the chaotic sedimentary breccias in the olistostromes of the Nose of Howth Group. Blocks in the Censure and Nose of Howth Groups are up to 450 m and 700 m across respectively. The turbidies have come from the southeast and east whereas the slumping appears to have been generated from the southwest.Slumping during sedimentation was followed closely by large‐scale folding and sliding of sedimentary or tectono‐sedimentary origin, and the bulk appearance of the sediments is due to these sedimentary and tectono‐sedimentary mechanisms. The main structure is an easterly facing, steep plunging syncline which locally is associated with a poorly preserved cleavage. This structure predated the main penetrative cleavage which is not axial planar to it.
The stratigraphy of Ordovician volcanic rocks on the southern and eastern flanks of the Harlech Dome in Merionethshire
Authors: Ridgway J. 
Published: July 2010

AbstractThe stratigraphy of nine areas of Ordovician volcanic rocks flanking the Harlech Dome is dcscribed and a correlation of the Ordoyician volcanic succession from Arenig to Cader Idris proposed. Nine formations are distinguished which together form a distinct lithostratigraphic unit termed the Aran Volcanic Group. At least six disconformities can bc recognised within the Group.
Gravity stratification in the Freetown Basic Igneous Layered Complex, Sierra Leone, West Africa
Authors: Umeji A. C. 
Published: July 2010

AbstractAn area of 78 sq. km in the vicinity of Freetown is mapped for the first time. By systematic mapping and study of about 1,500 thin sections, nine macro layered units have been recognized in this lowest exposed part of the intrusion. Each unit grades upward from magnetite or olivine‐rich layers, through pyroxene‐rich to plagioclase‐rich rock. Field data of fine‐scale layering, ‘false‐bedded’ layers and slumping are given. These and other sedimentary structures and features indicate that the Freetown magma was convective. It is suggested that rhythmic layering in the Freetown basic intrusion originated from slow accumulation of density‐sorted crystals which precipitated simultaneously from the magna‐pulses.
Jointing and minor tectonics of the S. Crop of the South Wales Coalfield between Machen and Bridgend
Authors: Roberts J. C. 
Published: July 2010

AbstractObservations on joints, minor faults and mineral veins at 47 localities along the south and south east crop of the S. Wales Coalfield indicate the presence of a joint system comprised of up to 6 sets of fractures striking at 350°, 330°, 290°, 270°, 250° and 210°. The joint sets are parallel to minor faults of strike and dip‐slip types, whilst minor thrust faults indicate an early phase of sub‐horizontal compression. The joint system is thought to be of tectonic origin and developed early in the deformational history of the area in response to a N‐S compression. Later, dilational episodes facilitated the infilling of mineral veins, with the W.N.W. trending set probably indicating the latest phase of dilation in the area. All structures are considered to be of Armorican age, whilst the marked similarity in the orientation of the joint system to that of the North Crop of the Coalfield suggests that the brittle deformation was relatively homogeneous on both flanks of the Coalfield.
The succession of the Lower Old Red Sandstone (Siluro‐Devonian) along the Ross‐Tewkesbury Spur Motorway (M.50), Hereford and Worcester
Authors: Allen J. R. L. , Dineley D. L. 
Published: July 2010

AbstractThe motorway cuts approximately 1900 m of strata, of which about 56 per cent are continuously exposed in numerous long sections, a new standard being afforded for the Lower Old Red Sandstone in the southern Welsh Borders. The succession recognized is:LOWER OLD RED SANDSTONEBrownstones (L. Dev.) at least 795 mSt. Maughan's Group (L. Dev.) 630 mRaglan Marl Group (Siluro‐Dev.) 385 mClifford's Mesne Sandstone (Sil.) at least 9 mLUDLOW SERIES (Silurian) at least 5 mThe uppermost Ludlow Series and the Clifford's Mesne Sandstone are exposed in the core of the May Hill‐Woolhope upfold. They are overlain in the complimentary syncline to the west by the Raglan Marl Group, St. Maughan's Group and Brownstones, in ascending order. Above the Clifford's Mesne Sandstone, there is a progressive upward increase in the number and thickness of sandstone relative to mudstone beds. Pedogenic limestones are largely concentrated in two short stratigraphic intervals. The lowest, mainly in the uppermost Raglan Marl Group but reaching into the St. Maughan's Group, includes the “Psammosteus” Limestone recognised elsewhere in the area. The second concentration occurs in the uppermost St. Maughan's Group. Vertebrates in the Raglan Marl Group and the St. Maughan's Group allow the Downtonian and Dittonian “stages” to be recognized.
A rediscovered 114‐foot Lepidodendron from Bolton, Lancashire
Authors: Thomas B. A. , Watson Joan 
Published: July 2010

AbstractSixteen specimens of known heights from a Lepidodendron trunk, about 34·5 m long, are described in detail. The surface features show upward change from fissured bark to well defined leaf cushions. These features are discussed in relation to growth patterns in arborescent lycopods.
Erosion surfaces and ignimbrite eruption, measures of Andean uplift in northern Peru
Authors: Myers J. S. 
Published: July 2010

AbstractRemnants of five mature erosion surfaces occur on the rugged western flank of the Andes, and each is deeply incised. They indicate alternation of arid with more humid conditions, and that the western Andes were raised in five major pulses from a subdued early Tertiary landscape of volcanic flows. Each pulse of uplift was accompanied by south‐westward tilting of the older erosion surfaces. The surfaces developed before an ignimbrite was erupted down the ancestoral Rio Fortaleza valley 6 m.y. ago. Since then, renewed uplift has led to further incision of the main valleys and the formation of canyons.
The crystallisation and differentiation of a layered intrusion of hydrated alkali olivine‐basalt parentage at Rhiw, North Wales
Authors: Cattermole P. J. 
Published: July 2010

AbstractThree outcrops of hornblende‐bearing basic intrusives at Rhiw, S.W. Lleyn, are considered to represent faulted remnants of a single larger intrusion. The layered rock series evolved by fractional crystallisation of hydrated alkali olivine‐basalt magma which was emplaced as a number of distinct pulses. The trend of differentiation is similar to that for the Hawaiian series: alkali olivine basalt‐ hawaiite‐trachyte. Consideration is given to the respective roles of pO2 and pH2O in controlling the course of differentiation.
Upper Llandoverian Grogal Sandstones and Aberystwyth Grits in the New Quay area, Central Wales: A possible upwards transition from contourites to turbidites
Authors: Anketell J. M. , Lovell J. P. B. 
Published: July 2010

AbstractThe lower boundaries of the Aberystwyth Grits Formation and the underlying Grogal Sandstones Formation (new name) in the New Quay area are defined. The Grogal Sandstones Formation is described, and interpreted as a contourite deposit on a continental rise; we believe these are the first rocks in the British Isles to be identified as contourites. The transition within a few tens of metres from Grogal Sandstones Formation contourite facies, displaying bimodal current directions, to Aberystwyth Grits Formation turbidite facies, with unimodal current directions, can be seen well in two places on the coast southwest of New Quay. Regionally, an upward transition from finegrained contourites to turbidites of varying facies can be recognised. Our results are compatible with Ziegler's interpretation of early Upper Llandoverian palaeogeography.
A geological framework for the continental margin to the west of Ireland
Authors: Riddihough R. P. , Max M. D. 
Published: July 2010

AbstractOn the basis of newly released magnetic data, a major fault feature is traced southwest across the Irish continental shelf; along the northwestern margin of the Slyne‐Erris Trough, the northern termination of the Porcupine Seabight, and across the Porcupine Ridge toward the vicinity of the eastern termination of the Gibbs Fracture Zone. This major fault passes into, and is identified with, the Great Glen Fault system. Apparent sinistral movement of the order of 50–70 km along the fault displaces a feature tentatively identified as the Highland Boundary Fault. A weak magnetic feature is also identified that might represent the course of the Moine Thrust. The Slyne‐Erris Trough has been referred to as part of a ‘failed’ rift associated with the Seabight opening, but might instead be related to the wrench faulting similar to that seen elsewhere along the Great Glen Fault line. An apparent transform movement along the portion of the fault at the head of the Porcupine Seabight may relate to rifting and the generation of oceanic crust in the central part of the Seabight.Two possible courses for the westward continuation of the Hercynian Front are recognized, and a major Tertiary intrusive centre is identified and related to a zone of dyke swarms.
Ordovician palaeogeography of the southern and eastern flanks of the Harlech Dome, Merionethshire, North Wales
Authors: Ridgway J. 
Published: July 2010

AbstractThe Arenig to Caradoc palaeogeographic evolution of the Harlech Dome region is interpreted from a study of the volcanic and sedimentary successions on the eastern and southern flanks of the Dome. Acid ignimbrite volcanism is shown to have been associated with periods of uplift and intermediate to basic volcanism with periods of subsidence. The evolution of the region can be compared to that of an island arc.
The sequence of Silurian graptolite zones in the British Isles
Authors: Rickards R. B. 
Published: July 2010

AbstractMuch modern work on graptolite sequences in the British Isles has provided considerably greater detail regarding species occurrence and range than was available to Elles and Wood (1901‐18) and requires that the more refined zonal schemes of, for example, Rickards (1967, 1969, 1970) and Toghill (1968a) should be more fully discussed than was possible in Strachan (1971), Cocks et al. (1971), or Ziegler et al. (1974). The zonal scheme favoured by the writer is discussed zone by zone, and reference is made to the various difficulties which may obtain, to other zonal schemes in use, and to the questions of local, national and international usage. A summary range chart of British Silurian graptoloids is included as Table I.
Trace fossils from the Upper Ordovician (Caradoc) of the Berwyn Hills, Central Wales
Authors: Pickerill R. K. 
Published: July 2010

AbstractA suite of Caradocian trace fossils from the Berwyn Hills, Central Wales, are examined. They include forms produced by trilobites (Cruziana, Rusophycus, Trichophycus, Monomorphichnus), pelecypods (Lockeia), ?gastropods (?Imponoglyphus) and traces of debatable affinity probably produced by oligochaete and polychaete annelids, amphipods and crustaceans (Skolithos, Planotites, Teichichnus, Diplocraterion, Arenicolites, ?Gyrochorte, ?Palaeophycus, Vermiforichnus). Representatives of the Skolithos and Cruziana communities coexist in this assemblage and no subdivision into discrete ichnofacies is therefore possible. The trace fossils are examined in terms of their relationship to the structure and composition of Upper Ordovician communities and it is concluded that substrate and ecological controls were more important limiting environmental parameters than depth.
Llanvirn stratigraphy of the Galway‐Mayo border area, western Ireland
Authors: Archer J. B. 
Published: July 2010

AbstractThe Rosroe Formation is established as the lowest part of the Llanvirn succession exposed on the southern limb of the Mweelrea‐Partry Syncline. Lithological description is followed by interpretation in terms of two structurally controlled submarine fans, developed at the southern margin of the South Mayo Trough. A review of stratigraphic relations between succeeding parts of the Llanvirn succession leads to reinterpretation of the closing marine phases of the South Mayo Trough: northward slope progradation is inferred to have resulted in graduai northward spread of shallow water and emergent conditions.
Serpentinites and related rocks of Anglesey
Authors: Maltman A. J. 
Published: July 2010

AbstractA series of ultramafic igneous bodies occurs in the Pre‐Cambrian (Monian) metasedimentary rocks of Anglesey. The latter are finely‐banded semi‐pelites of greenschist facies and have undergone two main phases of deformation. Most of the structures are weakly developed near the intrusions where an irregular zone of epidote hornfels was produced. The ultramafic bodies were emplaced as peridotite magmas immediately prior to D. Thorough serpentinization followed and the resulting serpentinites have a variety of appearances. A later carbonatization was intense in places. The structures and textures of the intrusive rocks can be correlated with regional events. Various melagabbroic rocks, now highly altered, may be comagmatic with the peridotite although intruded rather later.
Jointing and minor tectonics of the South Gower Peninsula between Mumbles Head and Rhossilli Bay, South Wales.
Authors: Roberts J. C. 
Published: July 2010

AbstractJoints and other minor structural elements were recorded at 429 stations on the S. Gower coast. A systematic pattern exists comprised of up to 6 sets of joints which strike at 360°, 340°, 290°, 270°, 240° and 200°. Joint set maxima are frequently parallel to the strike of major and minor faults, but no simple geometric relationship exists between joint orientation and fold axis trend. Axial‐trace‐fracturing has been recognized, whilst en echelon gash arrays, mineralized joint sets and their cross‐cutting relationships enable a tectonic sequence of events to be determined. The systematic joints are thought to have developed during the folding under the influence of a N–S compression, but variation in the strike of minor structures suggests a swing in orientation of o through time. Subsequent stress relaxation facilitated dilation and the production of mineralized vein suites.
The envjronment of deposition of the Caradoc Alternata Limestone and contiguous deposits of Salop
Authors: Hurst J. M. 
Published: July 2010

AbstractThe middle Caradoc rocks of Salop are a mosaic of sedimentary facies deposited in nearshore environments. The uppermost Horderley Sandstone in the Onny Valley is interpreted as formed by migrating marine bars and proximal and distal stonn deposits. The time equivalent Chatwall Sandstone of the Chatwall district is interpreted as a beach sequence. The overlying Alternata Limestone is a product of both proximal and distal storm deposits, associated with marine bars, in which different faunal assemblages are mized. Correlation of local sections is difficult due to facies and faunal changes and non‐deposition events. Based on a sedimentary model and palaeoecological information it is suggested that the Alternata Limestone in the Chatwall area is older than elsewhere, and that the base of the Cheney Longville Flags youngs southwards. Four faunal events are defined based on transect collecting, discriminant function and cluster analysis. These are theHowellites antiquior, Dalmanella leptaandBancroftina robusteAssociations and theHeterorthis alternatainterregnum.
The age, stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District
Authors: McNamara K. J. 
Published: July 2010

AbstractThe Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.
A cyclicity in the early Brigantian (D2) limestones east of the Clwydian Range, North Wales and its use in correlation
Authors: Somerville I. D. 
Published: July 2010

AbstractFor the first time, minor cyclicity is described from some limestones in the lower part of the Brigantian (D2) succession of the Mold district North Wales which can be traced throughout the area enabling a detailed correlation to be established. The minor cyclicity may have been caused by eustatic sea‐level fluctuations. Periods of emergence associated with each regressive phase are demonstrated by the presence of subaerial features and terrestrial deposits. The lateral persistence of the cycles is confirmed by comparison with established faunal and lithological horizons. Correlation with other cyclic Brigantian strata in Yorkshire, Derbyshire and Bristol is briefly discussed. The Asbian/Brigantian (D1/D2) boundary in North Wales is described and distinctive faunal and lithological changes similar to those in the area of the stratotype in north England have been recorded.
An Upper Llandoverian turbidite sequence of the Bwlch‐glas area, near Aberystwyth, Dyfed
Authors: Strong G. E. 
Published: July 2010

AbstractPetrographical investigation of an Upper Llandoverian turbidite sequence has been undertaken in conjunction with the primary 1:50,000 geological survey of the Aberystwyth District (Sheet 163) by R. Cave and B. A. Hains of the Institute of Geological Sciences. The sequence represents distal thin‐bedded turbidite deposition in a NW‐SE channel, with material derived from the southeast.
Late Pleistocene rock‐basin lakes in South Wales
Authors: Culver S. J. , Bull P. A. 
Published: July 2010

AbstractLaminated silts and clays recovered by coring and drilling in Swansea Bay are shown to be of lacustrine origin. Similar deposits penetrated by boreholes onshore in the Swansea area have also been ascribed to a lacustrine origin by several authors; a map showing the shape and distribution of five lakes in this area has been produced. Stratigraphic relationships and palynological evidence indicate that the lacustrine conditions probably lasted from about 16,000 to 10,000 years B.P.
Geomagnetic polarity measurements from Pleistocene deposits in Southwest France and their chronological implications
Authors: Oldfield F. , Thompson R. 
Published: July 2010

AbstractMeasurements of palaeomagnetic inclination in sediments from the French Pays Basque, representing three of the major Pleistocene biostratigraphic subdivisions previously identified, confirm normal polarity in all cases. Taken together with the palaeobotanical, stratigraphic and geomorphological evidence they suggest that the Moulignan, Senixian and Ilbarritzian stages lie within the early part of the present Brunhes normal polarity epoch and probably correlate with some unknown part of the “Cromerian Complex”. The Bidartian is thought to lie within a normal polarity event during the Matuyama epoch and to correlate with part of the Tiglian ‘A’ sub‐stage of the Netherlands.
The Longdendale landslides
Authors: Johnson R. H. , Walthall S. 
Published: July 2010

AbstractThroughout its geomorphological history the South Pennine valley of Longdendale has been especially prone to landsliding and some ten landslide areas have been identified. These prove on analysis to be bedding plane slides with a strong degree of translation but often exhibiting non‐circular rotational elements as well. Instability in the lower slopes has often led to cambering and valley bulging so that the slopes become deformed and slump earth flows developed at some sites. Several different types of landslide are examined in detail and by means of pollen analysis the slides are dated from the early postglacial to at least as recently as two thousand years B.P. although it has not yet been possible to decide when these slides started. The causes of sliding are identified, and comments are made upon.
The location of slip surfaces–which are frequently at the base of the Grindslow Shales above a sandstone aquifer.
The geomorphic processes which built up high pore‐water pressures and steep pressure gradients in the past.
The effects of sliding on the development of hillslopes in the post‐glacial period.
Authigenic iron and titanium oxides in Triassic red beds: (St. Bees Sandstone), Cumbria, Northern England
Authors: Ixer R. A. , Turner P. , Waugh B. 
Published: July 2010

AbstractAuthigenic iron and titanium oxides occur in three main textural varieties in the St. Bees Sandstone, a Triassic red bed succession in Cumbria. These are: (a) overgrowths of haematite, titaniferous haematite, anatase, and rutile which generally occur on detrital host grains of similar compositions. The overgrowths may occur as syntaxial rim cements or rhombohedral and prismatic projections and are always in optical continuity, (b) discrete crystals of anatase (including octahedrite) and haematite 10‐40 μm in size occur in pore spaces, and (c) fine grained ( < 1 μm) pigmentary haematite occurs as grain coatings around detrital grains and in the interstitial matrix.The euhedral nature and pore‐filling habit clearly indicate the authigenic origin of these iron‐ and titanium oxides. All three textural varieties are believed to have been precipitated from ground waters containing dissolved ferrous and titanium ions. These ions were derived from the intrastratal solution of detrital iron and titanium bearing grains including ferromagnesian silicates and iron‐titanium oxides. The precipitation of iron oxides from migrating ground waters in the manner described here goes some way to explaining how thick, uniformly red successions can be formed.
The age, stratigraphy and genesis of the coniston limestone group in the southern lake district
Authors: McNamara K. J. 
Published: July 2010

AbstractThe Coniston Limestone Group (Ashgill Series) in the southern Lake District shows greater lithological variation and lateral facies variation than hitherto suspected. The oldest part, the Longsleddale and Stile End Formations, is shown to correlate with the Cautleyan Stage, Zone 2, at Cautley; consequently the entire Coniston Limestone Group in the southern Lake District is considered to belong within the Ashgill Series. In the early Cautleyan, sedimentation was largely influenced by a central ridge which extended northward into a southerly transgressive sea. Later Cautleyan and Rawtheyan sedimentation was affected by an area of positive tectonic activity in the east of the region.