bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Note on the Occurrence of Ortho-Amphibolites on the Inner Shelf off Bhatkal, West Coast of India
Authors: Siddiquie H. N. , Karisiddaiah S. M. , Subrahmanyam V. 
Published: November 2024

Abstract
The total magnetic intensity map of the area shows that the inner shelf to a depth of 50m is marked by a zone of magnetic closures. The occurrence of offshore ortho-amphibolites and the qualitative interpretation of the magnetic map indicate the extension of onshore rocks (or the amphibolites and associated rocks of Precambrian (?) and intrusions of Deccan Trap age) under a thin cover of sediments to the offshore to a depth of about 50 m.
Textural and Mineralogical Studies of the Beach Sands from Fort Cochin to Chellanam, Kerala
Authors: Purandara B. K. , Unnikrishnan V. P. , Srinivas Gupta C. , Dora Y. L. 
Published: November 2024

Abstract
In general most of the beach sediments from the area under study are medium sand-sized, unimodal, moderately sorted, nearly symmetrical and mesokurtic in terms of their grain-size distribution. The standard deviation shows minor variations from September to December. The heavy minerals commonly found in these sediments in the order of decreasing abundance are hornblende, opaques, hypersthene, garnet, mica, sillimanite, augite and diopside. The percentage of quartz in the light mineral fraction varies from 57% to 99%. The provenance of these beach sands is believed to be the rocks of the Western Ghats - charnockite and gneissic terrain.
The Central Himalayan Gneisses in Northern Pakistan
Authors: Broughton R. D. , Windley B. F. 
Published: November 2024

Abstract
The Central Himalayan Gneisses on the northern margin of the Indian plate in the Hazara and Lower Swat areas of N. Pakistan comprise; orthogneisses with minor schists, amphibolites and calc-silicates, overlain unconformably by a cover sequence of graphitic and calcareous schists, marbles and minor amphibolites. These rocks are bounded to the south by a major thrust (equivalent to the Himalayan Main Central Thrust), and to the north by lhe Main Mantle Thrust (Indus Suture). To the south of the MCT there is a thrust slice of basement paragneisses with no relics of cover. The dominant gneissose foliation parallels the main thrusts, and is modified by numerous, large-scale N-S trending open folds.
The ortho- and para-gneisses and cover sequence are isofacial, and underwent two phases of metamorphism, prior to 35 Ma. Mineral equilibria indicate conditions for the cover sequence in the range 550-620°C and 8.0-8.9 kb, and for the paragneiss basement at ~650°C and 6.7-6.8 kb. The two pressure ranges come from different thrust slabs. These data indicate an average cooling rate of ~17°C my-1, and an average uplift rate of ~0.8 mm yr-1 over the last 35 My, for the relic cover sequence.
Tectonics of the Main Central Thrust in Garhwal Himalaya, U.P
Authors: Bahuguna V. K. , Saklani P. S. 
Published: November 2024

Abstract
The Main Central Thrust in Garhwal Himalaya is characterized by a duplex system. The relationship between the minor duplexes with the major Central Crystalline Duplex is investigated with the help of branch-line maps and balanced cross-sections. A probable model for the thrusting is suggested. Development and growth of Central Crystalline Duplex was caused by the repeated cyclic straining in the hanging-wall during the emplacement of thrust sheets. The contraction of the minor duplexes, namely, the Bhagirathi, Bhilangana and Mandakini varied from - 55.8% to -138%.
Bone Histology as a Tool for the Search of Dinosaurs
Authors: Mathur U. B. , Pant S. C. 
Published: November 2024

Abstract
Morphologically unidentifiable bone fragmenls from Jurassic of Jaisalmer (Raja-sthan) and Infratrappean of Kutch (Gujarat) were recently identified to be dinosaurian by their histological examination under petrographic microscope. This was feasible because the tissue structure of dinosaur bones is different from other contemporaneous vertebrates. It is characterised by the occurrence of dense Haversian systems of many generations in greater part of cortex. The note deals with the structure of Haversian System, its mode of occurrence and the methodology for identifying dinosaur bone fragments. It is hoped that the knowledge of bone histology will help in the discovery of new horizons and localities in India where only a few occurrences are known so far.
Delhi Volcanics in Parts of Central Rajasthan and their Significance
Authors: Gupta P. , Mukhopadhyay K. , Bose Utpal 
Published: November 2024

Abstract
The Proterozoic Delhi Supergroup of rocks along the Aravalli orographic axis in central Rajasthan encloses thick linear piles of syn-sedimentary volcanics. The volcanies are low-potassic oceanic tholeiites derived from mantle source. The repository basin was ensialic to start with and was partially rifted to facilitate magma upwelling concomitant with sedimentation. Structural stratigraphic and chemical characters of the volcanics militate against the possibility of its being allochthonous slices of an oceanic crust.
Geomicrobiology as an Aid to Prospecting: A Critical Study from Malanjkhand and Zawar Base Metal Deposits, India
Authors: Shrivastava J. P. , Alexander P. O. 
Published: November 2024

Abstract
Cold extractable and total Cu, Zn and Pb in soils arc faithful pointers to concealed mineralisation. Geomicrobiological studies have failed to give positive results. Thiobacillus ferrooxidanS, T. nevellus, T. permetabolis, T. thiooxidans, T. thioparus in soils over the mineralised zones were not detected in the present study. But cultures grown in P.D.A. media have shown quantitative differences for the mineralised and non-minearalised soils. Several possible reasons for this negative geomicrobiological response are discussed which include: deficiency in Mo and organic carbon in soils. unfavourable pH of soils/water, lack of moisture and water-logging among others. More detailed study of soil geomicrobiology minerai exploration is suggested.
Mineralogy and Element Variations in the Vindhyan Stromatolites, Central India
Authors: Kumar S. 
Published: November 2024

Abstract
The Lower Vindhyan stromatolites are dominantly made up of dolomite while the Upper Vindhyan stromatolites are made up of calcite. Sr shows sympathetic relationship with CaO and K2O with Al2O3. Three distinct assemblages of stromatolites belonging to the Kajrahat Limestone, the Fawn Limestone and the Bhander Formation show different trace element distribution.
Tectonic and Stratigraphic Framework of the Lead-Zinc Sulphide Mineralisation at Zawarmala, District Udaipur, Rajasthan
Authors: Singh N. N. 
Published: November 2024

Abstract
The carbonate-hosted lead-zinc sulphide mineralisation of Zawarmala belongs to the early Proterozoic rocks of the Aravalli Supergroup. The floor of the Aravalli sedimentation was a peneplained Archaean basement whose antiquity, as revealed by the recent Sm/Nd isotope studies, dating back to 3.5 billion years ago. The sedimentary package of the Arava11i Supergroup represents a sequence showing a distinct dichotomy in its depositional and lithological characters. The sulphide mineralisation is entirely confined to the near-shore shelf sequence which shows diverse lithofacies association of carbonates, black shales, argillites and arenites. By contrast, the distal (deep water) facies rocks which do not show any sign of syngenetic mineral deposits of any kind, is a totally carhonate-free sequence of argillites with thin bands of arenites.
The Aravalli Supergroup includes two groups separated by an unconformity marked by conglomerates and palaeo-erosional surfaces. The lead-zinc sulphide ores are confined to the carbonate sequence which occurs in the Upper Aravalli Group. Studies on the host rocks and the orebodies indicate a common plan of deformation and metamorphism. The geometry of the ore lenses suggests a very strong influence of the second deformation (AF2). This is also apparent in the trend surface maps showing distribution pattern of the metals-lead and zinc. Localisation of sphalerite, galena, and pyrite-bearing orebodies indicates differential mobilisation of these minerals in response to repeated deformation and metamorphism under a low temperature condition. The present study reveals a polygenetic history of the Zawarmala ore-bodies comparabte with those proposed for 'Alpine or Mississippi ValIey' types.
The Mid-Proterozoic Vindhyan Macrobiota from Chopan, Southeast Uttar Pradesh
Authors: Maithy P. K. , Babu Rupendra 
Published: November 2024

Abstract
Macrobiota comprising body fossils and trace fossils are reported from the Semri and Kaimur Groups of the Vindhyan Supergroup exposed around Chopan. Carbonaceous compressions of Chuaria minima and Tawuia dalensis, impressions of Sekwia excentrica and moulds of Longfengsahnia chopanensis sp. nov. are reported from the Rohtas Limestone Formation, Semri Group. Beside these, Longfengsahnia stiplala and epirelief of trace fossils belonging to possibly annelids are reported from the Ghurma Shale Formation of Kaimur Group. The macrobiota record indicates that during the Rohtas time free planktonic forms were present in the entire Vindhyan region particularly the genus Chuaria which may be considered as an index fossil of that period.
Alveolina from Western Kutch-Systematics, Distribution and Stratigraphic Significance
Authors: Ray A. K. , Ghosh C. C. , Nag S. 
Published: November 2024

Abstract
Alveolina of Kutch Middle Eocene limestones and marls is identified as A. elliptica var. nuttalli. The variety is shown to have a characteristic shape (expressed as a ratio of polar and equatorial diameters), and more or less fixed number of flosculinised whorls; the variation in the development of non-flosculinised whor1s on the flosculinised ones is attributed to an ontogenetic development correlated with size increase. The variety shows a clear case of lateral facies variation, occurring in two 'apparent' horizons in deeper parts of the basin with vertical absence in between, but continuing throughout the rock unit in marginal shallower parts. The facies-governed nature of this larger benthic foraminiferal species and its presence in the Kutch Paleogene sequence without the earlier glomalveoline forms are considered important aspects in stratigraphic studies.
Trace Metals in Ferromanganese Nodules and Host Sediments of the Indian Ocean
Authors: Ghosh Swapan K. 
Published: November 2024

Abstract
Ferromanganese nodules and host sediments collected from Indian ocean were successively treated with distilled water, acetic-acid buffer, acidic solution of H2O2, Oxalic acid buffer and citrate-bicarbonate-dithionile solutions, to relate the partitioning of trace elements, and their chemical association with iron and manganese oxide phases.
Based on the selective dissolution analysis of samples, it is suggested that host sediments contain higher abundance of crystalline oxides of iron and manganese than that in ferromanganese nodules. It was, however, observed that most of trace metals in sediments are concentrated in non-crystalline ferric hydroxide, although its concentration is less than crystalline ferric oxide. Nodules contained much higher abundance of trace metals, both in their crystalline and in non-crystalline phases.
In addition to the crystalline and non-crystalline iron and manganese oxides, a significant amount of trace metals occurs as substitutions of Ca and Mg in carbonates, and also as absorbed ions and as loosely bonded ions. Presence of carbonates and status of crystallinity of oxides of iron and manganese are identifiable by selective-dissolution analysis as proposed in this work.
A Geophysical Appraisal of the Purana Basins of India
Authors: Ramakrishna T. S. , Chayanulu A. Y. S. R. 
Published: November 2024

Abstract
Out of the six Purana basins, namely Cuddapah, Kaladgi, Bhima, Pakhal, Chattisgarh and Vindhyan, Cuddapah, Pakhal and Chattisgarh appear to be filled with rocks of higher than normal density, whereas the other three comprise low density rocks. Their gravity picture, however, are not found to be simple highs or lows as to be expected from their densities but are distorted by both deepseated causes as in the case of Cuddapah, Chattisgarh and Vindhyan basins, as well as the overlying sediments as in the case of Pakhal basin. Major earth movements appear to have been associated with Cuddapah, Pakhal, Vindhyan and Chattisgarh basins whereas Kaladgi and Bhima basins represent mere depressions. The thickness of sediments in these basins is estimated to vary from 2 to 10 km.
Petrology of Lamprophyres from Parts of East Garo Hills and West Khasi Hills Districts, Meghalaya
Authors: Raghavan Nambiar A. 
Published: November 2024

Abstract
Lamprophyres occur as dykes and veins in the Precambrian gneisses and granitoid country rocks along and in the vicinity of tbe Nongchram Fault Zone in East Garo and West Khasi Hills Districts of Meghalaya. They arc genetically associated with feldsputhie ijolites, tinguaites and carbonatites. They are typically melanocratic and contain leucocratic ocelli, spherical or sub-spherical in shape with a centrally disposed core of carbonates and alkali feldspar, mica and clinopyroxene-rich lining. The carbonate-rich inner zones of these zoned ocelli are interpreted as space originally occupied by a gas phase, whereas the outer zones represent late stage liquids. The mineralogy and chemical parameters of these lamprophyres coupled with the common presence of ocelli and megacrysts of mafic minerals and their genetic association with sodic alkaline rocks and carbonatite classify them as alkaline lamprophyres. Petrographically, the holocrystalline rocks can be classified as camptonites and the chilled dyke margins as monchiquites.
The occurrence is suggestive of rift-related alkaline magmatism. These alkaline and related rocks together with the ultramafic-alkaline-carbonatite complex of Sung Valley may constitute an ill-defined alkaline province. Their genetic link with Sylhet Trap volcanics cannot be ruled out, as eruption of alkali basalts is generally followed by alkaline intrusions.
A Note on the Occurrence of Ptilophyllum Flora from the Chintalapudi Sub-Basin, Pranhita-Godavari Valley, Khammam District, Andhra Pradesh
Authors: Lakshminarayana G. , Kutumba Rao N. 
Published: November 2024

Abstract
Ptilophyllum flora comprising Ptilophyllum cutchensis Cladophlebis denticulata,Cladophlebis Sp. Araucarites cutchensis, Araucorites Sp. (?) Elatocladus Sp. is reported from the buff siltstones and claystones of Dammapeta area, Chintalapudi sub-basin, Khammam District, Andhra Pradesh. The floral assemblage clearly indicates that the Dammapeta beds' belong to the Upper Gondwana, possibly Gangapur Formation and not Kamthi Formation (Lower Gondwana Group), as hitherto believed.
Granite-Molybdenite System of Ambalavayal, Kerala: Part I. Geochemistry and Petrogenesis of the Granite
Authors: Santosh M. 
Published: November 2024

Abstract
The 595 Ma old granite pluton punctures Precambrian low-alumina trondhjemites and occurs spatially related to the Moyar and Calicut fault-lineament. Mineralogically, it is a quartz-alkali-feldspar granite. Molybdenite occurs as disseminated flakes in the granite and associated pegmatites and as flaky aggregates in quartz veins. K: Na : Ca relationship suggests an adamellitic composition, whereas SiO2 vs. Log10K2O/MgO proportions confirm its alkaline nature. In Harker variation diagrams, the oxide weight percentages show overall magmatic trends. Among trace elements, the notable features are low large ion lithophile element contents, moderate to high transition element levels and extremely high light rare earth element values. High SiO2, K2O and Na2O values, with low abundance of Ba, Rb and Sr and enrichment of Nb and Zr are typical features comparable to alkali granites elsewhere. The Rb, Nb and Y characteristics denote a within-plate affinity. Petrochemical features indicate derivation of the granite from an alkali-enriched partial melt through quartz and alkali feldspar fractionation. The extremely high K/Rb values imply a K-enriched, Rb-depleted deep crustal source. The enrichment of LREE and HFS elements indicate an active role of CO2-rich volatiles in the petrogenetic regime.
Granite-Molybdenite System of Ambalavayal, Kerala: Part II. Nature of Mineralization, Sulphur Isotopes, Fluid Characteristics and Genetic Model
Authors: Santosh M. 
Published: November 2024

Abstract
The alkali granite pluton of Amba]avayal in Wynad district, Kerala, carries an 800m wide zone of disseminated molybdenite mineralization. Molybdenite also occurs as flakes and flaky aggregates in pegmatites and quartz veins. XRD and geochemical data indicate the molybdenite to be hexagonal 2H1 polytype. The general mineralogic and geochemical features of the granite are consonant with those of granite molybdenite systems in general. The sulphur isotope values in five molybdenite separates range from -1.62 to + 1.54 ‰, denoting a narrow spread and a single igneous source. Fluid inclusions commonly occur in quartz associated with the granite, pegmatites and quartz veins. Heating-freezing studies show that the granite quartz entrapped high density (0.90-0.95 g/cm3) CO2-rich fluids at pressures of 4.5-5.2 Kb. Coexisting CO2 and CO2-H2O inclusions in pegmatites yield a P-T estimate of 2.2 Kb and 500°C. Fluid inclusions in the mineralized quartz veins show that the ore-forming fluids (with a maximum salinity of 15 wt. % NaCl) were heterogeneous and the molybdenite precipitation was triggered by adiabatic decompression and 'boiling' at temperatures of 340-360°C and vapor pressures of 110-150 bars. The cooling curve of the granite constructed from combined P-V-T data shows a T-convex path, implying near-isolhermal upward movement of the granite magma. The data are consistent with a genetic model linking magmatism and metallogeny with extensional tectonics in the late Precambrian.
Secular Trends in Rare Earth Element Patterns of Precambrian Iron-Formations from India and Greenland
Authors: Appel Peter W. Uitterdijk , Mahabaleswar B. 
Published: November 2024

Abstract
Rare earth element (REE) analysis have been carried out by neutron activation on samples of iron-formation from southern India and from West Greenland. The investigated iron-formations range in age from about 1800 m. y. to more than 3000 m. y. The different iron-formations have undergone very diffeferent metamorphic histories, from the virtually unmetamorphosed iron-formation in West Greenland, through amphibolite to granulite facies metamorphism in southern India.
The results clearly demonstrate that europium anomalies cannot be used as indicators for oxygen contents of the Precambrian atmosphere. A secular trend has been established in the Precambrian iron-formations, whereby the oldest iron-formations display only slight fractionation of light REE relative to heavy REE, and this fractionas tion increases with decreasing age of the iron-formations.
The Jutogh Group of Metasediments of the Himachal Himalaya: Its Lithostratigraphy
Authors: Srikantia S. V. , Bhargava O. N. 
Published: November 2024

Abstract
The Jutogh Group of the Himachal Himalaya is divisible into eleven formations based on normal order of superposition, lithological association, lateral persistence and systematic mapping. This study helps greatly in reconstructing the sedimentary history, structural evolution and promoting better inter-regional correlation.
Mineralogical Characterisation of the Complex Sulphide Ores from Askot, Pithoragarh District, U.P
Authors: Acharya B. C. 
Published: November 2024

Abstract
Sphalerite, galena, chalcopyrite and arsenopyrite are the dominant ore minerals with minor amounts of pyrrhotite, cubanite, marcasite, pyrite and chalcocite. Bornite, stibnite, native bismuth and silver are present in trace quantities. Chemical analyses of the samples reveal variations in different metal values. Sphalerite, galena, chalcopyrite and arsenopyrite are analysed by Scanning Electron Microscope coupled with EDAX analyser to decipher the distribution of valuable elements in them.
The ore needs grinding to 45 microns to liberate 91.70% of galena, 94.49% of sphalerite, 95.31% of chalcopyrite and 98.45% of composite galena-chalcopyrite-sphalerite. This suggests that by physical beneficiation, individual concentrates of Pb, Cu and Zn with good recoveries may be difficult to obtain, but a bulk concentrate of these three metals can be produced.
Geology and Geochemistry of Spinifex-Textured Peridotitic Komatiite from Mayasandra Schist Belt, Karnataka
Authors: Charan S. N. , Naqvi S. M. , Ramesh S. L. 
Published: November 2024

Abstract
Spinifex-textured peridotitic komatiite occurs on the southeastern margin of Mayasandra schist belt near Nagamangala in Karnataka. Preservation of spinifex-texture made up of pseudomorphically altered phenocrysts of olivine and less commonly clinopyroxene set in a groundrnass of skeletal augite and devitrified glass in the komatiite, is essentially perfect in spite of alteration, deformation and metamorphism. Petrography shows dissimilar shapes and dimensions of the crystals, with more than one pattern of crystal arrangement in the texturally layered komatiite, clearly indicating that conditions and rates of crystallization were not uniform throughout the cooling unit. Compositional variations in terms of major and trace elements appear to be broadly consistent with fractionation of olivine followed by clinopyroxene. The high contents of MgO, Ni, Cr and extremely low percentages of TiO2, Na2O, K2O in the spinifex-textured ultramafic komatHte compare favourably with similar rock types reported from Canada, S. Africa and Australia.
On the Evolution of the Godavari Gondwana Graben, based on LANDSAT Imagery Interpretation
Authors: Ramanamurthy B. V. , Parthasarathy E. V. R. 
Published: November 2024

Abstract
Lineaments numbering about 110, show two major preferred directions, i.e., northwest-southeast and northeast-southwest. Majority of the lineaments are believed to be of Archaean ancestry. The Precambrian Pakhal, Sullavai, and the upper Palaeozoic to Mesozoic Gondwana sediments were deposited largely in a fault-controlled, successively developed troughs, broadly trending in a northwest-southeast direction. A five-stage tectonic evolution of the Godavari basin is envisaged. Absence of volcanism, and the narrow rift zones, place the Godavari Graben in the 'Crevice' type of platform rift zone of Milonovsky (1972).
Post-Triassic Earth Expansion Perhaps Caused by A Cometary Impact in Tibet
Authors: Shields Oakley 
Published: November 2024

Abstract
Plate tectonic models for wide ocean basins in pre-Jurassic times do not agree with paleomagnetism, craton and orogenic belt coherence, and continental growth, nor to post-Triassic exponential increase in ocean surface area and great circle and antipode symmetries, while expanding earth models do. Rapid earth expansion since the Triassic may be due to a hypervelocity cometary impact in Tibet that fractured a continuous sialic crust into continents, initiating seafloor spreading and the Tethys Sea. The impact as ejected debris from an exploded rlanet between Mars and Jupiter agrees with Van Flandern's theory of comet origin.