bluuebunny/crossref_metadata_2025_split huggingface dataset:
Taxonomy and stratigraphy of the Indian species of Discocyclina (foraminifera)
Authors: Samanta B. K. 
Published: May 2009

SUMMARYTwenty-seven specific and subspecific names have been proposed for discocyclines from the Indian region. Only 18 of them are considered to be valid. The morphological features used for distinguishing these forms are listed and their distribution in different parts of this region is described. On the basis of the character of the megalospheric embryonic apparatus, size of the test and the thickness of the equatorial chamber layer they are arranged in three groups. The tentative phylogeny of these three closely related groups of forms is discussed.
A new genus of Polyzoa (Cryptostomata) from the Devonian of New South Wales, Australia
Authors: Wass Robin E. , Byrnes J. G. 
Published: May 2009

SUMMARYIgnotrypa multivincula gen. et sp. nov., (Polyzoa, Cryptostomata), is described and figured from the Lower Devonian Garra and Nubrigyn Formations of central western New South Wales. It has a typical fenestrate meshwork but the carinae are thickened and joined laterally by numerous connections.
Formation of the Red Sea Depression
Authors: Whiteman A. J. 
Published: May 2009

SUMMARYVarious views have been expressed about the origin of the Red Sea Depression. Many earth scientists favour large-scale crustal separation and rotation of Arabia with respect to Africa—the paar theory; whereas a minority believe in a simple tensional origin. In the writer's view the almost “timeless” models presented by Drake & Girdler (1964) and Laughton (1966) are unacceptable because little of the available stratigraphic, structural and geo-morphological data was utilized in their construction. A tension system may have existed in the Red Sea area in late Pre-Cambrian and early Palaeozoic times. A depression existed in the northern part of the region in Carboniferous times and during Cretaceous times a tongue of Tethys occupied the northern and central portions of the depression. In Miocene times an extensive evaporite basin developed occupying most of the depression. The sill was situated in the Gulf of Suez Ayun Musa area.The main and central troughs developed as a result of tension in Pliocene and later times. The Gulf of Aqaba Depression was formed by a fault system continuous with Dead Sea System which originated in (?) early Cretaceous times. The northern and central parts of the gulf were invaded by the sea in Pleistocene times.The escarpments which bound the Red Sea Depression are in very few places fault or fault line scarps. Primarily they appear to be erosional features developed by pediplanation across the downwarped margins of the depression. In places, the shoulders and flanks were faulted later. In this way the uncon-formable nature of the contact, between the Mesozoic-Tertiary sediments and the Basement Complex (mainly Pre-Cambrian) which occurs at the foot of the escarpments, is best explained.
A gravity interpretation of the Liruei Younger Granite Ring Complex of Northern Nigeria
Authors: Ajakaiye Deborah E. 
Published: May 2009

SUMMARYGravity readings were taken on a 40-km traverse running roughly NE-SW across the Liruei Younger Granite ring complex of Nigeria. A negative Bouguer gravity anomaly of about 16 milligals amplitude was observed over the complex.Electronic computing methods were used in the interpretation to obtain the best 2-dimensional and 3-dimensional structures which would fit the observed anomaly. The best computed models indicate that the contacts between the Liruei Complex and the surrounding Basement Complex dip outwards from the ring complex and, based on the surface density contrast of 0·10 gm/cc, the depth to the base of the density contrast is of the order of 7,500 metres.
Mineral layering in the Galway Granite, Connemara, Eire
Authors: Claxton Charles W. 
Published: May 2009

SUMMARYExamples of semi-horizontal mineral layering in adamellites from the Galway Granite Batholith of Co. Galway, Eire, are described and illustrated. The layering results from variation in the amounts of the constituent minerals in successive horizons of the granite. It is suggested that the layering originated by settling of the early crystallizing minerals during quiescent periods in the emplacement of the granite, and that it may have been much more extensively developed than it is at present. Volatile constituents are thought to have reduced the viscosity of the magma periodically.
Soda-granites from South of Tatanagar, Bihar, India
Authors: Banerji A. K. , Talapatra A. K. 
Published: May 2009

AbstractThe nature and origin of some soda-granites from the western part of the Singhbhum shear zone, Bihar, India, are discussed. These soda-granites are responsible for copper sulphide, apatite-magnetite, and uraniferous mineralization within the shear zone. Earlier workers regarded these rocks as sheared materials representing a portion of the high sodic residual liquid from the neighbouring Singhbhum granite magma. The present work indicates that these rocks are migmatitic in nature and are the products of progressive replacement of pre-existing pelitic and semi-pelitic schists by felspathic materials. Migmatization is essentially post-shearing in age while the Singhbhum granite is pre-shearing in age. The migmatitic materials appear to have been derived by the partial melting of the Singhbhum granite during shearing, particularly in depth, as a result of sudden release of confining pressure consequent upon shearing and generation of heat caused by friction at the base of the shear zone. The resulting liquids, which were albite rich, found easy passage through the shear zone and brought about migmatization and mineralization in its wake.
A Model of the Structural Development of Israel and Adjacent Areas Since Upper Cretaceous Times
Authors: Freund Raphael 
Published: May 2009

AbstractThe rifting of the Red Sea, the folding of the Zagros-Taurus range (in Turkey and Iran), and the development of the structures in and near Israel appear to have resulted from a northward anti-clockwise rotational movement of Arabia, which occurred in several phases during Upper Cretaceous to Pleistocene times. The sinistral strike slip fault of the Dead Sea Fault system participated in this movement. It is hereby suggested that the fold and fault structures in Israel and adjacent areas are drag effects along this strike slip fault.
The Siluro-Devonian Boundary
Authors: Holland C. H. 
Published: May 2009

AbstractThe positioning of the Siluro-Devonian boundary is reviewed in the light of recent studies in both shelly and graptolitic facies in Europe and elsewhere. A case can be made for retaining the present position at the base of the Ludlow Bone Bed; but international opinion may demand a new standard section in the graptolitic facies, for example in Central Europe. In this event, it is suggested that a position at the base of the Monograptus uniformis Zone might prove the most widely satisfactory solution.
The Liassic Succession in a Clay Pit at Kirton in Lindsey, North Lincolnshire
Authors: Howarth M. K. , Rawson P. F. 
Published: May 2009

AbstractA new clay pit at Kirton in Lindsey, Lincolnshire, gives continuous exposures of 21 feet of clays and limestone nodules of the davoei Zone at the top of the Lower Lias, 18 feet of similar beds and 8 feet of Marlstone Rock Bed belonging to the Middle Lias, and 38 feet of shales and limestones of the tenuicostatum and falciferum Zones of the Upper Lias. Liparoceratid, Amaltheid, Dactylioceratid and Hildoceratid ammonites occur and allow the zones to be delimited with some accuracy.
Origin of Ultrabasic and Basic Gneiss Masses in the Lewisian
Authors: O'Hara M. J. 
Published: May 2009

AbstractIt has been suggested that the ultrabasic and basic gneiss masses in the Lewisian near Scourie and Drumbeg are layered igneous bodies possibly containing primary igneous mineral assemblages. This hypothesis is reviewed in all its aspects and rejected on the grounds of field relationships, mineralogy, and geochemistry.
Significance of Punctae and Pustules in Brachiopods
Authors: Kemežys K. J. 
Published: May 2009

AbstractA geometric model is proposed to explain the quincunx pattern of punctae which characterizes most terebratuloids. This model gives the two parametersdandg, which together express the density of punctae. The pattern of punctae in dalmanelloids does not differ in its basic geometry from that of the terebratuloids and can be defined by the same parameters. This also holds for the punctate spiriferoids and the punctate orthotetid genusStreptorhynchus. The pattern of pustules in the taleolate brachiopods differs from that of the model for the quincunx pattern of punctae, but can still be expressed in terms ofdandg. In this casedcorresponds to the wavelength of the costellae.Both punctae and pustules are morphologically and numerically related to the marginal setae.
Undersaturated Potassic Lavas and Hypabyssal Intrusives in North Johore
Authors: Grubb P. L. C. 
Published: May 2009

AbstractAn interesting occurrence of highly potassic lavas and hypabyssal intrusives of assumed Tertiary age is described from North Johore. The thickest lava flow is gravitatively differentiated showing a basal horizon of potassic ankaramite and basanite grading up into highly potassic bolitized flow tops of leucite-tephrite composition. Evidently the parent magma was close to a biotite pyroxenite in composition and possibly an assimilation product of peridotite by granite.
The sub-surface shape of part of the Loch Ailsh Intrusion, Assynt, as deduced from magnetic anomalies across the contact, with a note on traverses across the Loch Borralan Complex
Authors: Parsons Ian 
Published: May 2009

AbstractLocal magnetic anomalies of large magnitude are found over the marginal ultrabasic rocks of the Loch Ailsh intrusion. An intrepretation of these anomalies based on the measured magnetic properties of the pyroxenites shows that they are not reconcilable with a low-angle structure as required by the hypothesis that the intrusion is a stratified laccolite, and suggests that they form a steeply dipping sheet at the syenite-limestone contact. Similar anomalies occur along the southern margin of the Loch Borralan complex, suggesting steeply dipping marginal ultrabasic rocks.
Zeolite Facies and Regional Rank of Bituminous Coals
Authors: Kisch Hanan J. 
Published: May 2009

AbstractDiagnostic analcime-, heulandite-, and laumontite-bearing mineral assemblages from four areas in the Upper Carboniferous and the Permian of New South Wales have been correlated with the rank of the associated coals, represented by the carbon content of vitrinite. The coals are high-volatile bituminous to semi-anthracitic; their vitrinites contain from about 82 per cent up to an estimated 91 per cent carbon. Analcime-quartz is found associated with the lower-rank, the laumontite-rich assemblages with the higher-rank coals. Comparison with a similar correlation in Northern Yakutia (U.S.S.R.) indicates that diagnostic zeolites are not necessarily associated with coals of the same range of rank in different areas. Unlike the occurrence and stability range of burial metamorphic zeolitic assemblages, degree of coalification is probably independent of partial pressures of H2O and CO2: it is controlled mainly by maximum depth of burial, its duration, and the geothermal gradient.
Notes on cystoids
Authors: Paul C. R. C. 
Published: May 2009

SUMMARY“Strobilocystites? kearsargensis Stauffer,” a supposed rhombiferan cystoid from the Kennett Formation, Kearsarge, California, is a diploporite cystoid tentatively assigned to Revalocystis Jaekel. This extends the stratigraphic range of the Dactylocystidae into the Silurian and is the first reported occurrence of Dactylocystidae from North America. An unusual specimen of Glansicystis baccata (Forbes) with IL1 represented by two small pentagonal plates is described. Glansicystis had four short ambulacra: I and IV have only one brachiole; II and V may have one to three brachioles.An isolated echinoderm plate with structures which may represent pectinirhombs is described from the Whipple Cave Formation, Near Lund, Nevada. The structures differ from typical pectinirhombs and are older (Uppermost Cambrian or Basal Ordovician) than any previously described pectinirhombs.
Interglacial deposits at Wortwell, Norfolk
Authors: Sparks B. W. , West R. G. 
Published: May 2009

SUMMARYInterglacial organic deposits, at Wortwell in Norfolk, containing bones of Elephas antiquus, plant remains and molluscs, are shown to be of Ipswichian age. The plant and molluscan assemblages of an early part of the interglacial and of the mixed oak forest zone are described and compared with similar assemblages from Ipswichian and Hoxnian deposits. The relation between this deposit and other local Pleistocene deposits in the Waveney Valley is discussed.
Some Nomenclatural Problems in the Inarticulate Brachiopods
Authors: Rowell A. J. 
Published: May 2009

AbstractFive nomenclatural problems in the inarticulate brachiopods are discussed and solutions suggested for them. Two new genera, Eodinobolus, type species Obolellina magnifica Billings, 1872 and Orthisocrania, type species Pseudocrania divaricata M'Coy, 1851 are erected. Clistotrema nom. nov. for Orbicella d'Orbigny, 1847 non Orbicella Dana, 1846 is proposed.
Tonstein Bands in the Coalfields of the East Midlands
Authors: Eden R. A. , Elliot R. W. , Elliott R. E. , Young B. R. 
Published: May 2009

AbstractKaolinite-mudstone bands, widely recoginzed in the Carboniferous of Western Europe, where they are known as tonsteins, are also represented in Britain. On the basis of the probable correlation eight such bands have so far been found in the Coal Measures of the East Midlands. Laterally two of these bands are thought to pass into rocks intermediate in type between tonstein and more normal Coal Measures mudstones.
On the Age Relations of the Connemara Migmatites and the Galway Granite, West of Ireland
Authors: Leake B. E. , Leggo P. J. 
Published: May 2009

AbstractContrary to a previously published view, evidence is given to show that the Galway Granite is entirely later than both the quartzandesine migmatization and the potash-felspar migmatization in Connemara, and that the Oughterard Granite is probably earlier than the Galway Granite, not later. There is also strong evidence against regarding the foliated marginal granite of the north and north-east border of the Galway Granite as being different in origin from the marginal granite often found in the southern, western, and north-western borders. These results agree with the radio-chemical date of 365 m.y. determined for part of the Galway Granite.
Evolution of the Caledonides in the northern Trondheim region, Central Norway: a review
Authors: Roberts David , Springer Janet , Wolff Fr. Chr. 
Published: May 2009

SummaryA résumé of the stratigraphy, sedimentation and volcanism of the Lower Palaeozoic rocks in the northern Trondheim region is presented. Spatially the Caledonian rocks occupy a shallow trough which plunges south-west. Within the trough the rocks have been subject to four episodes of deformation; the essential structure of the region is an anticline flanked by recumbent fold nappes (F1) which spill outwards on either side of the NE-trending spine. These are deformed by further major folds (F2). The F3 folds, developed widely but only on a mesoscopic scale, show a constant down-dip sense of overturning. It is thought that they were formed in response to gravitational sliding. F4 is represented only by local kink bands. It is probable that large areas of these Cambro-Silurian rocks are allochthonous, the marginal thrust being of late-F2 age. Examination of the structures is illuminating many other aspects of the geology of this segment of the Caledonian chain, making it possible to visualize the changing sequences of deformation, the relationship of metamorphism to tectonic level and the tectonic behaviour of domal granitic masses. In conclusion, comments are made on the relative significance of the orogenic ‘disturbances’ described from this part of Norway.
The Upper Eocene Brockenhurst Bed
Authors: Martini E. 
Published: May 2009

SummaryCalcareous nannoplankton from the Brockenhurst Bed of Whitecliff Bay, Isle of Wight, belong to zone NP 20 of the standard Palaeogene calcareous nannoplankton zonation, indicating that the stratigraphic position of the Brockenhurst Bed is in the uppermost Eocene, and not equivalent to the type Lattorfian (Lower Oligocene).
Notes on the Triassic biostratigraphy of Svalbard
Authors: Tozer E. T. , Parker J. R. 
Published: May 2009

SUMMARYA revised interpretation of the sequence of marine invertebrate faunas from the Svalbard Triassic is given. Correlations are made with the unusually complete sequence now recognized in Canada. The position of the faunas is given in terms of the recently proposed lithostratigraphic scheme. In the Lower Triassic, Griesbachian, Dienerian, Smithian and Spathian faunas are represented; in the Middle, Anisian and Ladinian. In the Upper Triassic only a small part of the Karnian is represented by a marine fauna. No new faunas are recorded but for the first time three ammonoid zones are discriminated within the Anisian.
Upward movement of granitic magma
Authors: Cann J. R. 
Published: May 2009

SummaryThe negative P-T slope of the wet melting curve of granite sets limits on the degree of upward movement of granitic magma formed at particular partial pressures of water vapour. Wet granite magma cannot rise very far from its place of formation, and only dry granite magma can be erupted as a liquid. This observation leads to a better understanding of the granitic structure of orogenic belts, and explains some of the apparently paradoxical aspects of granites. Other wet magmas would also not be expected to be erupted as liquids.
Palaeogene warping in the Isle of Wight
Authors: Daley B. , Edwards N. 
Published: May 2009

SummaryGentle folding or warping, of Lower Oligocene age, pre-dating the main post-Hamstead Beds folding, is indicated where the Bembridge Marls rest unconformably on eroded Bembridge Limestone. The folding appears to have been along generally NW–SE trending axes. This trend is compatible with penecontemporaneous and even earlier folding in Southern England and adjacent parts of north-western Europe. In Southern England, the main folding may have been earlier than the Miocene age generally accepted.
Intra-Lower Palaeozoic faults in the Southern Irish Sea Area
Authors: Baker J. W. 
Published: May 2009

SummaryThe deep-seated caledonoid lineaments which developed in conjunction with the L. Palaeozoic basins in Wales, S. Irish Sea and Co. Wexford, bounded elongated fault-blocks within the resistant basement and its cover; it is suggested that under compression these broke internally along contemporary, strike-slip cross-faults. In the Central Wales and N. Wales–SE Co.Wexford blocks the latter were principally E–W and N–S faults respectively. Repeated movements of diverse styles along members of all three suites have influenced sedimentalogic, volcanic, plutonic and geomorphologic events throughout the Phanerozoic; in particular, they permitted the Irish Sea Geanticline to rise above the roots of the Monian tectogene, and determined the form of the younger Irish Sea sedimentary basins.
Hydrothermal Alteration in the Carrock Fell Area, Cumberland, England
Authors: Ewart A. 
Published: May 2009

AbstractWithin this area are developed a series of quartz veins which cut three rock types, the Grainsgill granite, part of the southern margin of the Carrock Fell gabbro to the north, and an intervening area of hornfels belonging to the Skiddaw Slate Series. Both the hornfels and the gabbro have suffered thermal metamorphism due to the granite, and in addition, the hornfels has undergone a very localized metamorphism due to the gabbro. All three rock types have undergone a further hydrothermal alteration due to the quartz veins. The microscopic changes involved in this alteration are described and it is shown that the end product in each case is essentially similar to a greisen, with the addition of pyrite and arsenopyrite.
Sclerotinite in Coal—its Petrology and Classification
Authors: Taylor G. H. , Cook A. C. 
Published: May 2009

AbstractSome thousands of Australian coal samples have been studied at the Division of Coal Research, C.S.I.R.O. On the basis of these studies, the present usage of the term “sclerotinite” is considered and possible justifications for the retention of this maceral category are outlined and discussed. No characteristic differences in physical properties, form, or utilization behaviour have been found whereby sclerotinite may be distinguished from the other macerals of the inertinite group. Most of the material which has been referred to as sclerotinite is probably not fossil fungus. The “discrete body” category of sclerotinite may well represent fusinized resin bodies, while the more extensive material represents degraded plant tissue. There would appear to be no case for the retention of the maceral category sclerotinite, and alternative means are suggested of classifying for petrographic analysis material which has hitherto been regarded as coming within this category.
A Study of Quartz Orientation and its Relation to Movement in Shear Folds
Authors: Gangopadhyay P. K. , Johnson M. R. W. 
Published: May 2009

AbstractThe orientation of quartz in small shear folds, which belong to two movement episodes, is considered to result from laminar flow along the axial plane surfaces. The locations of fabric maxima and girdles are controlled by the orientation of thea–kinematic axis, which in shear folds may not be normal to the fold axis, and the shear surfaces. The earlier fabric consists, essentially, of paired maxima arranged systematically about the axial plane;ac–girdles are absent. The explanation of the near-orthorhombic symmetry of the first fabric in terms of a late “flattening” overprinted upon the previously-formed fold is not favoured: quartz orientation developed during the first folding. The later fabric results from the recrystallization of quartz grains with their largest dimensions andc–axes parallel to the calculateda–kinematic axis of second folding.
Cleavages and Linear Structures in Ordovician Sandstones, Victoria
Authors: Beavis F. C. 
Published: May 2009

SummaryTwo cleavages occur in the sandstones: coarse fissuring, and a fine irregular fracturing, which may form conjugate sets. Linear structures of five styles, all of which are parallel to the fold axis, are developed on the bedding due to the intersection of this element by the cleavages.
Eustatic Control of Major Cyclic Changes in Jurassic Sedimentation
Authors: Hallam A. 
Published: May 2009

AbstractEvidence is sought to prove, with reference to five examples, that major cyclic changes in Jurassic sedimentation have been controlled by eustatic rises and falls of sea level. Abrupt variations suggestive of pronounced deepening of the sea in areas of marine sedimentation in Europe are correlated with extensive marine transgressions in widely separated parts of the world. A connection is recognized between eustatic movements and evolution and migration of the invertebrate fauna, and relationships between eustatic and local, epeirogenic movements outlined.