bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blocks of Plutonic Aspect in a Basaltic Lava from Faial, Azores
Authors: Baker M. Jane 
Published: May 2009

AbstractA 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

AbstractArising 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.
Serpentinites in the North-East Ox Mountains, Eire
Authors: Lemon G. G. 
Published: May 2009

AbstractSix 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.
Late Cromerian Fauna and Flora at Ostend, Norfolk
Authors: Stuart A. J. , West R. G. 
Published: May 2009

SummaryPollen 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

SummaryA 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

SummaryA 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

SummaryThe 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

SummaryThe 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

SummaryRecent 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

SummaryA 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

SummaryThe 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

SummaryThe 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

SummaryClassical 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

SummaryThe 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

SUMMARYThe 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

SUMMARYA 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

SUMMARYBased 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

SUMMARYThe 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.
A Note on Rhythmic Layering in Hornblende-rich Picrite and Dolerite Intrusions, near Rhiw, Caernarvonshire
Authors: Hawkins T. R. W. 
Published: May 2009

AbstractBanding, 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

AbstractThe 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

AbstractSediments 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

AbstractAn 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

AbstractA 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

AbstractA 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

AbstractThree 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

SUMMARYLower 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

SUMMARYDrift 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

AbstractLarge 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

AbstractEight 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

AbstractTwo 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

AbstractThe 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.
The stratigraphic distribution of the Ordovician inarticulate brachiopod Orthisocrania divaricata (M'Coy) in the British Isles
Authors: Wright A. D. 
Published: May 2009

SummaryThe 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

SummaryQuartz-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

SummaryThe 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).