bluuebunny/crossref_metadata_2025 huggingface dataset:
Pedogenic carbonates and flood sediment accretion rates: a quantitative model for alluvial arid-zone lithofacies
Authors: Leeder M. R.
Published: May 2009

A general model for pedogenic carbonate development in alluvial sediments is based upon of rates flood sediment accretion versus time taken for particular carbonate profiles to develop. Conclusions regarding rates of Holocene carbonate pedogenesis and the changing morphology and thicknesses of carbonate profiles with time are used to predict critical values of floodbasin accretion rates which would have enabled particular ancient profiles to develop. Local (intra-drainage basin) and regional profiles are separated and a number of models for calcrete genesis are outlined. The presence or absence of particular genetic stages of calcrete may be used as a rough guide to estimate ancient floodbasin accretion rates.
Underwater studies of recent lava flows around São Miguel (Azores)
Authors: Mapstone N. B. , Rood A. P. , Jackson N. G.
Published: May 2009

An underwater study of recent submarine lava flows on São Miguel (Azores) suggests that the island has subsided by as much as 9 m relative to sea level over the last few thousand years. A spectacular system of overlapping lava arch structures occur immediately below the ancient sea level, and they are thought to have formed when tongues of molten lava flowed over a steep autochthonous submarine scree slope. The scree was subsequently removed by strong longshore currents and wave action.
Trilobite traces and the age of the lowest part of the Ordovician reference section for NW Spain
Authors: Crimes T. P. , Marcos A.
Published: May 2009

A quartzite-shale sequence forming the lowest part of the Ordovician reference section for NW Spain in the Cantabrian zone at Cabo Peñas, lacks body fossils and has hitherto been of uncertain age. This sequence has, however, yielded a variety of trilobite-produced trace fossils. The lowest exposed beds haveCruziana breadstoniandRusophycussp. while a few tens of metres higherC. furcifera, C. goldfussi, C. rugosaandRusophycus asturiensissp.nov., are also present. The highest beds have yielded onlyC. furcifera. The traces suggest that while the top of the sequence is at least as high as Arenig the lowest beds are of Tremadoc (post-Dictyonema flabelliformeZone) age. This implies a thickness for the Arenig of no more than 400 m and probably considerably less. In contrast, thicknesses in excess of 1000 m occur to the W in the West Asturian–Leonese Zone. This, together with evidence of tidal to intertidal deposition at Cabo Peñas, tends to confirm that the area was the shelf to an Ordovician trough situated in the West Asturian–Leonese zone.
The charnockite series of Amaravathi, Gunter District, Andhra Pradesh, South India
Authors: Ramaswamy A. , Murty M. S.
Published: May 2009

The charnockite series consisting of pyroxene granulites and charnockites are not formed by magmatic differentiation, although both units had their antecedents in igneous material. The solid-state recrystallization of pyroxene granulite and the liquid-state crystallization of charnockite are inferred from the field criteria. The pyroxene granulites with the associated paragneisses are formed from the original sedimentary-volcanic sequence under granulite facies of metamorphism. The magmatic charnockites emplaced into these rocks resulting in the development of intermediate varieties by the partial assimilation and incorporation of the pyroxene granulites. The stability of the minerals is not affected by this migmatization, which is therefore thought to have taken place under granulite facies conditions. The evolutionary trend of the charnockite series is one of retrogression from the earlier granulite facies to the later almandine-amphibolite facies, caused by the subsequent granite invasion.
An Ophiceratid ammonoid from the New Zealand Permian and its implications for the Permian–Triassic boundary
Authors: Waterhouse J. B.
Published: May 2009

A nesw Ophiceratid genus and species Durvilleoceras woodmani is described from the late Middle Permian Greville Formation of New Zealand, with Episageceras aff noetlingi Haniel. The horizon is close in age to the Kathwai dolomite of the Salt Range, which also has a mid-Permian Ophiceratid species, Ophiceras connectens Schindewolf. The occurrence of these two species shows that the Ophiceratidae cannot serve as an index of early Triassic rocks. The so-called basal Triassic Griesbachian Stage may prove to be closely linked to the Permian period. The key Griesbachian ammonoid genus Otoceras is related to Permian genera, with no later survivors. Moreover the widespread occurrence of Permian-type Productacea and other brachiopods in beds of the Griesbachian Stage in North America and Himalayas also suggests that the Griesbachian is Permian rather than Triassic. To judge from faunas, the start of the Triassic could be based on the incoming of numerous ammonoid families and Triassic brachiopods in the Smithian Stage. The intervening Dienerian Stage between the Griesbachian and Smithian stages is relatively barren of faunas, reflecting some sort of catastrophe at the end of the Paleozoic Era, but has mainly Permian survivors. Such a picture of the Paleozoic–Mesozoic boundary conforms with the intention if not the practice of early paleontologists.
Basic magmatism in relation to metamorphism and orogeny in Guiana: a speculation
Authors: Choudhuri A.
Published: May 2009

The northern part of the Guiana Shield consists of large tracts of basic and intermediate volcanic rocks and sediments which are thought to have formed under geosynclinal conditions. During the 2000 m.y. Trans-Amazonian Orogeny these rocks were subjected to tectonism and metamorphism resulting in a broad belt of green schist facies with local and isolated patches of high grade metamorphic rocks and gneiss complexes. In the early stages of orogeny during which folding and probable block faulting of the sediments and volcanics took place, these rocks were intruded by basic and ultra-basic rocks giving rise to metagabbro-amphibolite-peridotite associations, commonly in the areas of subsequent high-grade metamorphism. In an attempt to account for the frequent supply of basic magma during and after the orogeny it is postulated that mantle peridotites rose diapir-like below the sinking geosyncline, and by partial melting not only provided basic magmas but also thermal energy which spread upwards to metamorphose the already tectonized crustal rocks; recent gravity measurements indicate an upwarped ‘sima’ under the Bartica Assemblage gneiss complex.
Petrological Evidence for the Presence of Amphibole in the Upper Mantle and its Petrogenetic and Geophysical Implications
Authors: Oxburgh E. R.
Published: May 2009

In addition to meeting various geophysical requirements, an ultrabasic upper mantle must provide a source both for olivine nodules and for the range of “primary” basaltic types, i.e. those which are apparently uncontaminated and undifferentiated. Potassium abundances and other considerations suggest that olivine nodules represent upper mantle which has previously yielded basalt by partial fusion but is now “barren”, principally because of potassium depletion, and is unable to yield more. The possible range of potassium contents of “parent” upper mantle (still able to yield basalt) is considered and it is argued that at any concentration within this range, the potassium is not distributed between the main mantle phases as a trace component but is contained largely within a potassium-rich minor phase. It is shown that this phase is probably an amphibole and may make up between 2 and 20 wt. per cent of parent upper mantle. In addition to the isochemical phase changes to be expected with increasing depth, a transition is proposed from an upper zone of amphibole-free (barren) upper mantle to a lower zone of amphibole-bearing (parent) upper mantle. The petrogenetic and geophysical implications of such a model are discussed; in particular it provides a possible explanation for the Gutenberg low-velocity zone.
A New Species of the Ostracod Genus Paijenborchella Kingma
Authors: Anderson F. W.
Published: May 2009

A new ostracod from the London Clay (Lower Eocene) of the London Basin is described as Paijenborchella geoffreyi sp. nov. and compared with other species of the genus.
A Seismic Refraction Section of the Preglacial Teifi Valley near Cenarth
Authors: Francis T. J. G.
Published: May 2009

A short seismic refraction line has been shot just north of Cenarth in Cardiganshire across the preglacial valley of the River Teifi. The deepest point on the Ordovician basement has been found to be 30 feet below O.D.
The Lower Carboniferous Rocks of the Castle Hill Fault Block, Tenby, Pembrokeshire
Authors: Sullivan R.
Published: May 2009

The rocks of Castle Hill previously considered to be of Tournaisian age are now shown to be referable to he Dibunophyllum Zone. The revised age greatly simplifies the structure of the fault block.
A Simple Grid Deviation Technique of Study of the Areal Composition Variations in Granitic Bodies
Authors: Saha Ajit Kumar
Published: May 2009

A method of preparing grid deviation maps for the representation of the areal composition variations in granitic bodies is described. A comparative study of this method and the trend surface method by using the data of forty-five modal analyses of Bahalda hornblende granodiorite indicates greater effectiveness of the former in several respects.
Siderite- and Calcite-bearing Concretionary Nodules in the Lias of Yorkshire
Authors: Hallam A.
Published: May 2009

Nodules containing siderite and calcite in the Yorkshire Lias have been studied quantitatively using petrographic, X-ray and chemical methods. Ankerite is recorded from the Lias for the first time. It is shown how the relative abundance of early diagenetic siderite and calcite correlates with sandiness of the sediment and provides an index of environmental change.
A New Interpretation of the Llandovery Sequence of North Connemara, Eire
Authors: Piper David J. W.
Published: May 2009

The historical development of the stratigraphic nomenclature of the Llandovery of north Connemara is described. The lowest beds are red sandstones and interbedding keratophyre passing up into a complex sequence of grey, green and red clastics with shelly facies fossils. Above this are red and green mudstones and siltstones with rare graptolites. In the east these are overlain by coarse sandstones and conglomerates. The conglomerates are probably allochthonous. In the west this coarse facies is developed earlier and laterally interfingers with the shelly facies clastics and overlying mudstones. The sub-Wenlock unconformity reported by McKerrow and Campbell from this region is reinterpreted as an appearance of this interfingering.
Belemnite Deformation at Fernigen, Switzerland
Authors: Johnson M. R. W.
Published: May 2009

Elongated belemnites illustrated by Albert and Arnold Heim were not deformed as brittle bodies, because the guards have undergone recrystallization. A tentative hypothesis is put forward to integrate the mechanical and chemical processes in the belemnites. During progressive extension of the belemnites carbonate material has diffused from highly stressed fragments of the guards into “low-stress” spaces between the fragments.
A Sagitta Zone Conodont Fauna from the Wenlockian of the Usk Inlier, Monmouthshire
Authors: Austin R. L. , Bassett M. G.
Published: May 2009

A conodont fauna from a thin limestone bed, considered to be of Wenlockian age, in the Usk inlier, Monmouthshire, is described. Ninety-seven specimens are assigned to four genera and eight species. The fauna is referable to the sagitta conodont zone and suggested correlations are made with the upper part of the Ostra-coden-Kalkes in Germany, with part of the Aulacopleura Schichten and Kok-Kalk in Austria, and with part of the Lockport Dolomite and Rochester Shale in North America.
Psigraptus, a New Graptolite Genus from the Tremadocian of Yukon, Canada
Authors: Jackson D. E.
Published: May 2009

The new genus, Psigraptus, containing P. arcticus n. sp. and genotype and P. lenzi is proposed for two-branched and three-branched reclined graptolites with isolate autothecae. The genus is known only from the Bryograptus-Clonograptus Zone (Tremadocian), Yukon Territory.
Fabric Analysis of a Deformed Vein
Authors: Nettle J. T.
Published: May 2009

The crystallographic orientation of optic axes, the crystallographic orientation of {0112} twins and the dimensional orientation of calcite from a drag folded vein are described. The external movements that have caused the deformation of the vein are interpreted and the fabric characteristics are related to them. The calcite fabric shows a marked similarity to those which have been produced experimentally. An analysis of the quartz fabrics demonstrates that there is no significant preferred orientation of optic axes.
Observations on the Speeton Clay (Lower Cretaceous)
Authors: Kaye Peter
Published: May 2009

The lithological succession in the upper part of the Speeton Clay of the type section is given and the classification of the clays as a whole is reviewed. Brief notes are included upon the mode of deposition of the sediments and the palaeogeography of the area in Lower Cretaceous times.
The Application of Vacuum Shadowing to the Examination and Photography of Small Objects
Authors: Krinsely D. , Morton N. , Cutbill J. L.
Published: May 2009

The technique of vacuum shadowing small objects and the advantages of this method in light photography are detailed. The ultra-thin metal-carbon films thus prepared show greater contrast and resoultion than acetate peel replicas.
Some Effects of Palaeozoic Folding on the Pre-Cambrian Rocks of the Frenchmans Cap Area, Tasmania
Authors: Spry A. , Gee D.
Published: May 2009

Small–scale isoclinal folds in Pre–Cambrian schists and quartzites near Frenchmans Cap, Tasmania, were formed during the Pre–Cambrian Frenchman Orogeny but the large open folds were produced during the Devonian Tabberabberan Orogeny. The Mary Antiform (Devonian) at the Raglan Range can be “unrolled” to leave the foliations almost horizontal, indicating that the isoclinal folds were recumbent prior to the Palaeozoic.
Studies in North Atlantic Geology and Palaeontology: 1. Upper Cretaceous
Authors: Funnell B. M.
Published: May 2009

An Upper Maastrichtian assemblage of planktonic foraminifera is recorded from chalk dredged from Galicia Bank, a non–magnetic seamount off the west coast of Spain. The occurrence and distribution of Upper Cretaceous sediments and fossils in the North Atlantic is reviewed, and their significance for the palaeogeography of the North Atlantic during the Upper Cretaceous is considered.
Boudinage-type Structures at Sørfinnset, Gildeskaal, North Norway
Authors: Bradshaw R. , Wells M. K.
Published: May 2009

A layer of massive and lineated hornblende-biotite-gneiss has fractured along ac-joints (perpendicular to the layering and b–lineation), at regular intervals along its lower surface in contact with a thin marble bed. The joints have been opened from below and the marble has penetrated upwards to form intrusive tongues caused by extremely plastic flow folding, as shown by the unbroken banding in the marble. The structure constitutes a variety of one-sided boudinage involving segmentation in the lowest metre or so of the hornblendic rock, while the extreme marble deformation is all accommodated in a few centimetres thickness. The structures must have developed at relatively high temperatures to allow contemporaneous segregation of quartz-feldspar pegmatite veins from the hornblendic rock, and of diopside reaction skarns at the marble junctions.
The Highland Boundary Fault in East Tyrone
Authors: Cobbing E. J.
Published: May 2009

Correlation of the metamorphic inlier of Co. Tyrone with the Connemara Schists, together with a reinterpretation of the"Tyrone Igneous Series" erected by J. J. Hartley, lends support to recent suggestions that the Highland Boundary Fault originated as a normal fault with downthrow to the north. The palaeogeographical implications of this are briefly discussed.
The Formation of Tension Joints in Sedimentary Rocks: An Explanation
Authors: Hobbs D. W.
Published: May 2009

A simple theoretical explanation is given for the formation of systematic tension joints in sedimentary rocks. This theory shows that the frequency of occurrence of joints in a bed of rock is dependent upon the physical properties of the rock bed, the physical properties of the surrounding rock beds, the thickness of the rock bed, and the degree of tectonic deformation.
Further Evidence for a Middle Würm Interstadial and a Main Würm Glaciation of South-west Wales
Authors: John Brian S.
Published: May 2009

At Cil-maenllwyd (Cardiganshire) glacial outwash sands were found to contain layers of small wood fragments. A radiocarbon age determination of 33,750 yrs B.P. indicates that the wood fragments are probably of Middle Würm age, and that the last glaciation of St. George's Channel occurred during the Main Würm. Pollen and spores contained in the sands suggest that the environment prior to the last glaciation was at one stage predominantly forested. The organic remains are thought to relate to the problematical “ Middle Würm Interstadial ”, rather than the Paudorf Interstadial.
Blocks of Plutonic Aspect in a Basaltic Lava from Faial, Azores
Authors: Baker M. Jane
Published: May 2009

A number of coarse-grained blocks, consisting of forsteritic olivine, chrome-diopside, calcic plagioclase, and chromite in varying proportions, were found in an ankaramitic basalt on Faial. With one exception, the blocks show remarkably little alteration. There is no evidence of zoning in any of the minerals. Indications of strain are frequent. Dark scoriaceous material is often present along intercrystal boundaries and fractures. The textures and gradations in composition suggest that these blocks were formed by crystal accumulation.
A Revision of the Lower Hecla Hoek Succession in Central North Spitsbergen and Correlation Elsewhere
Authors: Harland W. B. , Wallis R. H. , Gayer R. A.
Published: May 2009

Arising from detailed reassessment of field work in the area of Ny Friesland and Olav V Land from 1938 to 1965, a revised stratigraphical scheme is proposed for the Hecla Hoek succession which is known to range downward from Lower Ordovician and Lower Cambrian (1 km.) into a relatively unbroken sequence of Pre-Cambrian rocks about 19 km. thick. The metamorphosed older rocks, previously grouped as Lower Hecla Hoek, are reinterpreted as a succession 12 km. thick with a large volcanic component and a distinctive tillite horizon. Correlation is attempted anew with rocks elsewhere in Spitsbergen and overseas. The Hecla Hoek suite contributes to an interpretation of the development of the Caledonian tectonic province in late Pre-Cambrian and Lower Palaeozoic time.
A Note on the Dunite (Peridotite) Mylonites of St. Paul's Rocks (Atlantic)
Authors: Tilley C. E.
Published: May 2009

The mylonitic character of the peridotites of St. Paul's Rocks on the Mid-Atlantic Ridge was reported in a contribution by the writer (Tilley, 1947), these ultrabasics then being referred to as dunite or peridotite mylonites. The available chemical analytical data were assembled in that paper and a new analysis provided of a two-pyroxene representative. The type carrying porphyroclastic amphibole was represented by an analysis by Washington (1930) but it was shown that this analysis erred in its alkali determination, and that the reported occurrence of jadeite could not be confirmed.
Serpentinites in the North-East Ox Mountains, Eire
Authors: Lemon G. G.
Published: May 2009

Six serpentinites occur in the Moinian granulites of the North-East Ox Mountains. Four have been known for some time and have been previously described. Additional information on these and the associated vermiculite deposits is provided. The remaining two serpentinites are described for the first time. A pyroxenite vein associated with one of these may have been produced by meta-morphic regeneration.

The relationship of some of these serpentinites to the probable position of the Highland Boundary Fracture-zone in Eire is also discussed. Brief comparison is made with serpentinites occurring in the Scottish Moinian.
Kink-bands in Lower Carboniferous Slates of Rush, Co. Dublin
Authors: Dewey J. F.
Published: May 2009

Unusual single kink-band sets in calcareous slates are described and their mechanism of formation discussed. Regional inferences are drawn concerning Armorican strike-slip movements.
Late Cromerian Fauna and Flora at Ostend, Norfolk
Authors: Stuart A. J. , West R. G.
Published: May 2009

Pollen analyses have been made from sediments associated with vertebrate remains, includingArvicola cantiana, collected early in the 19th century from Ostend, Norfolk. They indicate that the fauna is of Cromerian zone IV date. Comparison with other pollen-dated Cromerian faunas implies that the early water voleMimomys saviniwas replaced by the more advancedA. cantianaduring the second half of the Cromerian temperate stage. This is important in setting possible age limits to the faunas of such sites as Westbury, Mauer and Vérteszöllös.
Andalusite in the Mullach nan Coirean granite, Inverness-shire
Authors: Haslam H. W.
Published: May 2009

A marginal variant of the Mullach nan Coirean granite contains orthoclase microperthite, quartz and plagioclase, with some andalusite, muscovite and iron ore. The stability of andalusite as an igneous mineral is discussed.
A gravity survey of the Bovey Tracy basin, Devon
Authors: Fasham M. J. R.
Published: May 2009

A detailed gravity survey, carried out to determine the thickness of the Bovey Tracey beds, is described. After removal of the regional gradient a residual gravity anomaly of – 15 mgal can be attributed to the Bovey beds. This has been interpreted assuming that the clay density increases with depth and a maximum Bovey bed thickness of 1245 m is predicted. The western contact of the basin is shown to be faulted with dips of up to 63° and is possibly an extension of the Lustleigh–Sticklepath fault system.
On the rotation of biotite from the pelites around Gruvehagen, Trondhjems Feltet, Norway and its genetic implications
Authors: Mukherjee Ananda Deb , Sen Ranendra N.
Published: May 2009

The occurrence of stout and stumpy crystals of biotite elongated parallel to the schistosity and showing askew cleavage is found to be due to rotation. The relation between rotation of biotite and deformation is described. Rotated biotite contains a higher amount of FeO, TiO2 and Al2O3 in comparison to the unrotated fresh and recrystallized biotite.
Petrological observations on alkali syenites of Kunavaram, A. P., India
Authors: Bose Mihir K. , Chakravarti S. , Sarkar A.
Published: May 2009

The alkali syenite assemblage of Kunavaram, Khammam district, Andhra Pradesh in south-eastern India, comprises perthite syenite and nepheline syenite. The massive perthite syenite (locally grading to alaskite) is fringed on either side by foliated nepheline syenite, the latter developing composite gneisses along the contact zones with the country rocks. The syenites are essentially hypersolvus although the alkali feldspar, the dominant constituent of the rocks, shows varying degrees of unmixing and Al/Si order. The mafic constituents (e.g.sodic pyroxene, amphibole and biotite) are appreciably rich in ferrous iron. Mineralogical and chemical data suggest that the primary crystallization characteristics of the syenites were not totally obliterated during the post-magmatic history of the pluton.
Pleistocene beds at Corton, Suffolk
Authors: Banham P.
Published: May 2009

Recent coastal erosion has revealed another chalky till above the Lowestoft Till and separated from it by bedded clays and sands. These have shown no evidence of contemporary life and, together with the newly discovered till, are assigned to the Lowestoft Stadial at this the type-section of the Anglian (Lowestoftian) Glacial Stage.
Age of cleavage in the Skiddaw Slates in relation to the Skiddaw aureole
Authors: Soper N. J. , Roberts D. E.
Published: May 2009

A recent hypothesis concerning the age of orogenic deformation of the Skiddaw Slates in the English Lake District has proposed that the main slaty cleavage (S1) and superimposed subhorizontal crenulation-cleavage (S2) are of intra-Ordovician age. A study of the fabric of the aureole of the (end-Silurian) Skiddaw granite shows that the granite was emplaced towards the end of the D1 deformation phase, but before the formation of S2. These structures are therefore of broadly end-Silurian age, and evidence of an intra-Ordovician orogeny in this area is lacking.
Fossil content and age of the greywacke formations west of the Leinster Granite in Counties Dublin, Kildare and Wicklow, Ireland
Authors: Brück P. M.
Published: May 2009

The Lower Palaeozoic strata west of the Leinster Granite in eastern Ireland, normally referred to as Ordovician, are mainly a greywacke sequence which lithologically resembles undoubted Silurian rocks elsewhere to the north and west. A scanty fauna occurs which could be either Ordovician or Silurian.
Textural distinction of Main Glaciation and Scottish Readvance tills in the Cumberland lowland
Authors: Huddart David
Published: May 2009

The sand/matrix ratio technique is described and has been shown to provide a rapid method of correlating till units in the Cumberland lowland which belong to separate glacial phases. Basal tills have a relatively constant sand/silt-matrix ratio compared with flowage tills in the same locality.
Facies relations in the Subathu Sediments, Simla Hills, Northwestern Himalaya, India
Authors: Raiverman V. , Raman K. S.
Published: May 2009

Classical works on Indian stratigraphy described three stratigraphic units, viz., Subathu, Dagshai and Kasauli within the Tertiary sequence of Simla Hills, India. Present work shows that the above three units represent mostly intertonguing among three distinct lithofacies, respectively termed as green, red and grey facies depending upon the dominant shale colour. Environmental significance of each facies is discussed. A road log presenting evidences of facies intertonguing on the basis of sedimentary structures is described.
Nahan Sandstone and its exfoliation, Nainital District, Uttar Pradesh, India
Authors: Das Brijraj K. , Vanshnarayan
Published: May 2009

The Nahan sandstone of the Nainital district is a soft, fine-grained sandstone of subgreywacke type. Like massive igneous rocks it is very well exfoliated and consists of many concentric layers. Petrographic study of different layers of this sandstone, modal analysis, grain size analysis, and size distribution of the various samples, have revealed that physical processes are mainly responsible for exfoliation of the sandstone. The study of various sedimentary parameters indicated that the provenance is from the schistose and granitic rocks of the surrounding Himalayan mountains and the material was deposited in a shallow slowly sinking basin.
Nature and origin of banding in the granitic sheets Tremearne, Porthleven, Cornwall
Authors: Stone Maurice
Published: May 2009

The granitic sheets of Tremearne are believed to have originated from the roof of the Tregonning granite and to have undergone lateral differentiation from leucogranite to aplite with associated pegmatite in a direction away from this granite. Several types of banding are described from the pegmatite-rich region at the Megiliggar Rocks. Some decimetre-scale banding is the result of intrusion of “magmatic” aplitic material, but coarse pegmatite bands are believed to have grown in solid aplite. A close examination of centimetre-scale banding and fine-banding in aplite (line rock) indicates that this is related to pegmatite development and is metasomatic. The mobility of alkalies and the concentration of potash in pegmatite relative to aplite is discussed.
Plant remains from the Corton Beds at Lowestoft, Suffolk
Authors: West R. G. , Wilson D. Gay
Published: May 2009

A flora found in a clay lens in the Corton Beds at Lowestoft indicates a late- or full-glacial type of environment during an interval in the deposition of the Corton Beds. The interval may be related to drainage changes associated with the retreat of the North Sea Drift ice and advance of the Lowestoft Till ice.
The Eocene succession of Garo Hills, Assam, India
Authors: Samanta Bimal K.
Published: May 2009

Based on the distribution of several stratigraphically important species three distinct larger foraminiferal zones are recognized in the Middle-Upper Eocene succession of Garo Hills, Assam, India. A comparison of these zones with larger foraminiferal assemblages from other Middle-Upper Eocene successions in the Indian region is attempted and observations are made on the demarcation of the Middle and Upper Eocene boundary and the classification of the Upper Eocene succession in this region.
The accumulation of sediment in the lee of ripples and dunes, and the thickness of bottomset deposits
Authors: Allen J. R. L.
Published: May 2009

The properties of bottomset deposits found in the lee of ripples and dunes formed in water depend on: (i) the diffusion and settling of grains driven over the crest of the sand body and (ii) the redistribution of grains over the bed due to the expenditure of fluid power in the recirculating eddy to the lee of the body. Experiment shows that the rate of grain settling in the lee of a sand body falls off hyperbolically downstream. The bottomset deposits of ripples and dunes also attenuate in thickness downstream, but reach a zero thickness commonly at 4–5 ripple- or dune-heights downstream from the crests. Bottomsets may consist partly or wholly of settled grains, but can also be formed when no sediment settles in the lee of a sand body.
Conical Folding and Sedimentary Lineations
Authors: Cummins W. A.
Published: May 2009

Recent studies of the effects of folding on the orientation of primary sedimentary lineations have been restricted to cylindrical folds. This work is now extended to include conical folds.
A Note on Rhythmic Layering in Hornblende-rich Picrite and Dolerite Intrusions, near Rhiw, Caernarvonshire
Authors: Hawkins T. R. W.
Published: May 2009

Banding, recorded by previous workers in hornblende picrite and dolerite intrusions near Rhiw, is found to be rhythmic layering. At least three major units (200 to 250 feet in thickness) have been recognized, and intermediate and minor scale units also occur, predominantly within the basal major unit. The majority of the rocks display cumulate textures, and crystallization appears to have been completed by heteradcumulus or adcumulus growth. Thin coarser-grained sheets, rich in plagioclase, and slightly discordant to the layering, are considered to be contemporaneous segregation veins.
Further Considerations on the Deposition of the Middle Cambrian Manganese Carbonate Beds of Wales and Newfoundland
Authors: Mohr P. A. , Allen R.
Published: May 2009

The succession of individual coloured bands in two manganese ore specimens has been analysed for eight trace elements, and has revealed some long-term chemical variations of possible regional extent throughout the period of ore deposition. Previous work on the distribution of elements between the three types of coloured ore banding is confirmed, and new data on the equivalent coloured bands of the contemporaneous Newfoundland manganese bed reveal an essential chemical, as well as lithological, identity of the two rocks. The effects of weathering and oxidation on ore geochemistry are discussed.
Evidence of a Late Pre-Cambrian Glaciation in the Kimberley Region of Western Australia
Authors: Dow D. B.
Published: May 2009

Sediments of late Pre-Cambrian age mapped in the Kimberley Region of Western Australia have all the characteristics of tillite, and their glacial origin is confirmed by: the presence of very large polished and striated erratics, the great diversity of megaclasts, their regional extent, and the presence of striated, grooved, and polished quartzite bedrock directly beneath the tillite.

Faceted and flat-iron-shaped pebbles are rare or absent; most megaclasts tend towards an ellipsoidal shape—an observation in agreement with recent theories of glacial abrasion.
Development of Schistosity in Flexural Folds
Authors: Mukhopadhyay D.
Published: May 2009

An example of the development of axial plane schistosity close to a buckled competent band is described. There is a difference in the degree of development of the schistosity on the convex and the concave sides of the fold arch. This is explained as due to variation in contact strain. A similar pattern has been produced experimentally and it is concluded that the axial plane schistosity in the example under consideration is a mechanical phenomenon and has developed perpendicular to the direction of maximum compressive strain.
Revision of the Stratigraphical Scheme for the Carboniferous and Permian Rocks of Spitsbergen and Bjørnøya
Authors: Cutbill J. L. , Challinor A.
Published: May 2009

A revised Stratigraphical scheme based on numerous measured sections and extensive mapping is proposed for the Carboniferous and Permian sequences of Spitsbergen and Bjørnøya, the important Arctic archipelago, in order to provide an up-to-date framework for future work there. New data on the fusulinid zones is summarized and the age of the sequence discussed. A brief Stratigraphical interpretation with four maps showing outcrops, thicknesses, active faults, and main lithological boundaries is given and recent published and unpublished work is reviewed.
The Morphology and Systematics of “Didymograptus”fasciculatusNicholson, 1869
Authors: Skevington David
Published: May 2009

A new description of “Didymograptus” fasciculatusNicholson, 1869, is given on the basis of specimens from the Skiddaw Slates (Zone ofDidymograptus bifidus) some of which are preserved in relief. The uniramous rhabdosomal form is confirmed. The presence of prothecal folds indicates that the species belongs in the family Sinograptidae Mu, 1957, and adoption of the generic nameNicholsonograptus, proposed by Bouček and Přibyl (1951) with “D. ” fasciculatusas the type species, is recommended. The possibility thatNicholsonograptus fasciculatusis an intraspecific variant ofHolmograptus lentus(Törnquist, 1911) is discussed.
Tertiary Fumaroles on the Island of Raasay, Inverness-shire
Authors: Selley R. C.
Published: May 2009

Three large pipes of brecciated Torridonian sediments set in matrices of calcite and calcareous mudstone occur on the island of Raasay. Previous work has shown that these structures may be due to explosive fumarole activity during the Tertiary volcanic episode. A recent study of the Torridonian stratigraphic succession has made it possible to demonstrate that there was considerable variation in the amount of vertical collapse of the local country rock caused by the explosions. In one vent local fracturing and brecciation took place with no downward movement; in another it is possible to show that Torridonian boulders tumbled at least 350 metres down into the throat of the fumarole. The amount of vertical collapse increases from vent to vent southwards towards the Cuillins volcanic centre.

These vents are of particular interest for two reasons. Though clearly of volcanic origin they contain no volcanic material. Secondly, the carbonate matrix of analogous structures is generally believed to be due to the hydrothermal solution of underlying limestone beds. The latter are absent in these examples and the carbonate material seems to be solely of volcanic origin.
Stratigraphy of the Lower Tertiary formations of Panjab Himalayas
Authors: Chaudhri R. S.
Published: May 2009

Lower Tertiary rocks of the Panjab Himalayas are classified under the Lower Tertiary System which comprises the Subathu Series (Upper Palaeocene-Eocene), the Dagshai Series (Upper Eocene-Lower Oligocene) and the Kasauli Series (Upper Oligocene-Lower Miocene). There is perfect stratigraphic harmony between the Subathus and the Dagshais, and the latter, in turn, grade into the Kasauli Series.

Correlation of the Lower Tertiary rocks of India, Pakistan and Burma and their European and North American equivalents is tabulated.
Low-potash dacite drift pumice from the Coral Sea
Authors: Bryan W. B.
Published: May 2009

Drift pumice collected in December, 1964, from the Herald Cays in the western Coral Sea is chemically and petrographically a dacite, unusually low in K2O and with very calcic plagioclase. It is apparently identical to pumice washed ashore in Fiji in March, 1965; both collections are divisible into light and dark varieties on megascopic, optical and chemical criteria. This pumice is distinguishable from the widely distributed pumice of the 1962 South Sandwich eruption; it is considered to have originated along the Tonga-Kermadec ridge on the basis of available seismic and compositional data.
Layered Xenoliths in a Dyke, Awatere Valley, New Zealand
Authors: Challis G. A.
Published: May 2009

Large cognate xenoliths showing rhythmic banding in anorthosite and pyroxenite are described from a camptonite dyke. Analyses of the camptonite, a pleochroic titanaugite and a titaniferous brown, hornblende are given.
Dalradian Pillow Lavas, Ardwell Bridge, Banffshire
Authors: MacGregor Sheila M. A. , Roberts John L.
Published: May 2009

Eight metabasic bands with pillow structures are exposed in a synclinal area immediately to the north-west of Read's (1955) position for the Boyne Line. Their petrography indicates (a) that they have undergone a sequence of metamorphic changes leading from the production of syntectonic biotite-albite-sphene-iron ore schists, through a stage of static annealing, to the development of post-tectonic amphibolites and (b) that they are of unusual chemical composition. Their stratigraphic position is discussed and compared with that of other occurrences of Dalradian pillow lavas, both in Scotland and in Ireland.
On Certain Slump Structures in the Torridonian Sandstones of Applecross
Authors: Stewart A. D.
Published: May 2009

Two types of slumps are described; small sag and drop-shaped structures in the fine sandstones which develop out of iron-ore rich laminae, and the much larger slump folds in the coarse sandstones which have wavelengths of 25 to 200 cm. and are characterized by open “synclines” linked by pointed “anticlines”. Complex structures are common. It is suggested that liquifaction of the lower parts of the slumped beds has resulted in collapse of the upper parts. Kuenen's pseudo-nodule experiments reproduce many of the observed structures.
Some Underwater Disturbances in the Torridonian of Skye and Raasay
Authors: Selley R. C. , Shearman D. J. , Sutton J. , Watson J.
Published: May 2009

The paper deals with disturbances of bedding contemporaneous with deposition in Torridonian rocks of Skye and Raasay. Most of the structures described have the general form of sharp upwardly-directed peaks separated by areas of more or less undisturbed bedding; within the peaks the bedding is often contorted or destroyed. The structures are developed in sandstones and are thought to have been formed more or less in situ by the shifting and rearrangement of quicksands. An origin as a result of slumping is rejected. The appearance of the structures is thought to be connected with the environment of deposition which appears to be that of very shallow water.
A Lower Ordovician Gastropod from Anglesey
Authors: Bates Denis E. B.
Published: May 2009

Matherella (?) acuticostata sp. nov. is described from the Lower Ordovician of Trefor, near Bryngwran, in mid Anglesey.
The Lower New Red Sandstone of the Crediton Valley
Authors: Hutchins P. F.
Published: May 2009

The Lower New Red Sandstone of Devon outcrops in a north-south band near Torquay to Exmoor. It rests unconformably on the Devonian and Culm. Westwards of Tiverton and again west of Exeter the outcrop extends into the Culm synclinorium. The Lower New Red sediments in the second and longer of these narrow tongues, together with the associated Hatherleigh, Highhampton and Essworthy outliers, form the subject of this paper.
The stratigraphic distribution of the Ordovician inarticulate brachiopod Orthisocrania divaricata (M'Coy) in the British Isles
Authors: Wright A. D.
Published: May 2009

The brachiopodOrthisocrania divaricata(M'Coy) is generally considered to be a fairly long-ranging form occurring in both the Caradoc and Ashgill Series. The latter age is based principally on records of its common occurrence from the Chair of Kildare, Ireland, but the species is not present in the Ashgill beds at this locality. It does occur there, however, in association with a fauna whose age is here judged to be Longvillian on the basis of its strong similarities to that of the Gelli-grin Calcareous Ashes. Examination of other records and occurrences suggests that this inarticulate is restricted to the Longvillian in the British Isles, and is therefore of some importance stratigraphically.
Distribution of volcanic rocks about mid-ocean ridges and the Kenya Rift Valley
Authors: Wright J. B.
Published: May 2009

Quartz-trachytic differentiates characterise volcanic islands on or near mid-ocean ridges, while phonolitic trends are found on islands rising from ocean basins. A large part of the Kenya Rift Valley is dominated by Plio-Pleistocene quartz-trachytes, which are underlain and flanked by variably nepheline-rich Miocene and Plio-Pleistocene lavas.

Phonolitic and nephelinitic lavas dominate the assemblages of Miocene age, trachytes and olivine basalts those of Plio-Pleistocence age. This change in petrographic character with time is attributed to two stages of sub-crustal pressure relief corresponding to Lower Miocene and late Pliocene elevations of the Kenya dome. The result was a change in partial melting products from less to more silicic, especially along the axial rift valley.

The doming movements and related vulcanism are believed to have originated because of lateral compression, induced by sea-floor spreading movements in the Atlantic and Indian oceans.
Redescription of the lectotypes of the Devonian tabulate corals Roemeria infundibulifera (Goldfuss), Roemeripora minor (Schlüter) and Favosites goldfussi d'Orbigny
Authors: Jell J. S. , Hill Dorothy
Published: May 2009

The lectotypes of the Devonian tabulate corals Roemeria infundibulifera (Goldfuss), Roemeripora minor (Schlüter) and Fovosites goldfussi d'Orbigny are redescribed from new thin sections. It is confirmed that Roemeria Edwards & Haime and Roemeripora Kraicz are best regarded as two separate genera of the Roemeriidae Pocta and that R. minor is best referred to Roemeripora. It is shown that internal characters of the lectotype of F. goldfussi are reasonably consistent with those taken as diagnostic for the species by Jones (1936) and Lecompte (1936, 1939).
Scour casts with inclined terraces
Authors: Whitaker J. H. McD.
Published: May 2009

A specimen from the Krosno Beds (Oligocene) of the Polish Carpathians shows irregular scour casts, in the shallower parts of which terracing is horizontal but in the deeper parts of which it is dipping at up to 27°. It is inferred the the original sea floor consisted of cross-laminated surface layers. The palaeocurrent significance of inclined terraces is discussed.
Carbonate deposition on the river floodplains of the Wood Bay Formation (Devonian) of Spitsbergen
Authors: Friend P. F. , Moody-Stuart M.
Published: May 2009

The argillaceous siltstones of the floodplains contain, on average, 15% of calcium carbonate. This appears to have been precipitated between the detrital grains shortly after their deposition. The siltstones also contain calcium carbonate concretions which formed as the ground water dried out in the upper part of the water table. Bedded marlstones, containing up to 68% of carbonate in the lakes appears to have been stimulated by Charophyte algae. The marlstones include dolomite in some parts of the Formation. The channel-fill deposits include carbonate detritus from the source areas, and from reworking of Wood Bay Formation sediments. They are frequently cemented by calcite.

The regional pattern of carbonate derivation, transportation and deposition is summarized.
A note on deformed igneous sheets in the Durness Limestone of the Strath district of Skye
Authors: Nicholson Robin
Published: May 2009

Clearly boudined and folded igneous sheets occur in Durness Limestone on the south side of the Tertiary Ben an Dubhaich granite. Obvious Tertiary dykes in nearby Mesozoic rocks are not deformed at all, nor has such deformation been described previously from the Caledonian activity in the Cambro-Ordovician of the north-west Highlands. Its appearance here does fit Clough's description (in Peach et al. 1907) of an unusually strong Caledonian penetrative deformation in the Strath Limestone, while the fact that all but one of the sheets are dolerites, a rock not elsewhere known from the Cambro-Ordovician but typical rather of the Tertiary activity for which Skye is famous, and that the other is a two feldspar porphyry very like the Ben an Dubhaich granite, point to the possibility of Tertiary deformation.
The Glacial Till of Fair Isle, Shetland
Authors: Flinn Derek
Published: May 2009

Reddish-brown glacial till containing millet seed sand grains occurs on Fair Isle, Shetland. Both the colour and the millet seed grains may have come from Permo-Triassic sandstones on the sea floor in the neighbourhood of Fair Isle, since the Devonian rocks of the area are not often red and do not give rise to till containing millet seed grains.
Echinoid preservation in the Upper Estuarine Limestone of Blisworth, Northamptonshire
Authors: Aslin C. J.
Published: May 2009

The study of echinoids and their associated limestones in the Upper Estuarine Series of Blisworth has shown that the echinoid tests have been preserved in two ways. (1) Without spines, jaw apparatus or apical disc. When whole, such tests are usually full of sediment. Echinoids of this type are usually associated with clean well-sorted fragmental limestones. (2) Bearing spines and with apical disc and jaw apparatus in place. When whole, the tests are usually full of clear crystalline calcite. Echinoids of this type are usually associated with poorly sorted, complex, muddy limestones with a high proportion of terrigenous material. The sedimentary environment and the relative rate at which the echinoid material passed through the depositional interface appears to have controlled both the limestone lithology and the condition of the echinoid material.
Paragenesis of a Cordierite-Garnet Granulile from Assam, India
Authors: Sastri G. G. K.
Published: May 2009

A cordierite-garnet granulite from Assam, India, carries optically positive cordierite, garnet, spinel, biotite, and sillimanite. The optics of the cordierite are: α = 1·534, β = 1·540, γ = 1·548, 2V = + 81°, while the composition of the garnet inferred from the writer's charts, in terms of the end-members, is Al73Py20Sp2An3Gr2. The development of an iron-rich garnet in association with a magnesium-rich cordierite is discussed, and data are presented to show that such garnets have a restricted compositional range. It is doubtful if the FeO/MgO ratio in a cordierite-garnet assemblage can be used for interpretation of the physical conditions governing the formation of the host rock.