bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geochemical Constraints on the Genesis Phosphorites of Chhattisgarh Basin, Durg District, M.P., India
Authors: Khan M. W. Y. , Mukherjee A. 
Published: November 2024

Abstract
This paper documents the geochemical and mineralogical characters of the phosphorite of Charmuria Formation (Chhattisgarh Basin). X-ray diffraction studies have revealed presence of carbonate fluorapatite as the only apatite mineral in this phosphorite, along with quartz as major gangue, and kaolinite-illite, calcite and pyrite in subordinate amounts. Structural formula of this apatite closely resembles carbonate fluorapatite. Further, CaO/P2O5 ratio (1.37 - 1.99) suggests that this phosphorite has not been affected by weathering. Quartz dominance over clay minerals and low CIA (24.79 - 46.87) is attributed to the tuffaceous nature of siliceous clays (lithofacies-A). The depletion of Sr, and trace elements of organic association in siliceous clays, phosphorite and phosphatic siliceous clays point to a common provenance.
Geodynamic Evolution of Indian Shield During Proterozoic: Geochemical Evidence from Mafic Volcanic Rocks
Authors: Raza M. , Jafri S. H. , Alvi S. H. , Shamim Khan M. 
Published: November 2024

Abstract
Geochemical data on Proterozoic volcanic rocks of Indian shield overwhelmingly suggest that tlhey were generated in two different tectonic settings. The mafic volcanic suites of Aravalli (Aravalli craton) and Bijawar (Rundelkhand craton) belts and those of lesser Himalayan region appear to be lift related continentat type. On the other hand Delhi volcanics (Aravalli craton), Dongargarh volcanics (Bhandara craton) and Dbanjori-Jagannathpur volcanics (Singhbhum craton) exliibit the characteristic signature of subduction zone magmatism implying the destruction of oceanic lithosphere by processes akin to those of modern plate tectonics. Geochemical and geological evidences suggest the occurrence of a nearly Proterozoic ocean in Central India located between Dharwar-Singbhum-Malwar rotocontinent in the south and Bundelkhand protocontinent in the north. During middle Proterozoic, the oceanic lithosphere subducted towards south along the northern margin of southern protocontinent. The lack of complete calc-alkaline series in the subduction - generated volcanic suites suggests that are volcanism along this margin could not acquire maturity and that the period of subduction was short lived. The collision of the two protocontinents led to the closure of ocean and induced the Satpura - Delhi orogeny at about 1500 m.y. ago-The ophiolitic seqeunce of Phulad (Delhi belt), Dalma (Singhbhum belt) and probably Tal (Bijawar belt) are the possible evidences of closure.
High-Alumina Hypersthene in a Basalt Flow from Mt. Sundook, Siberian Traps, Russia
Authors: Murari R. , Krishnamurthy P. , Gopalan K. S. , Nesterekno G. V. , Tihonenko P. I. 
Published: November 2024

Abstract
Electron probe microanalysis (EPMA) and preliminary x- ray diffraction studies on a basalt flow from Mt.Sundook have revealed the presence of rare high-alumina hypersthene in the groundmass. The basalt occurs at the base of a 800 m flow sequence (Ivakinsky and Syverminsky suite) that unconformably overlies a Permo-Carboniferous sedimentary sequences. It is postulated that besides normal processes of fractionation, assimilation-fractional Crystallization (AFC) processes involving the parental magma and crustal components (pelitic sedinientary rocks) were responsible for the formation of hypersthene in the basalt. The presence of a complex feldspar and pyroxene assemblage may also be an additional evidence for the operation of such an AFC process.
Tectonic Setting, Petrochemistry and Tungsten Metallogeny of the Sewariya Granite in the South Delhi Fold Belt, Rajasthan
Authors: Bhattacharjer J. , Fareeduddin  , Jain S. S. 
Published: November 2024

Abstract
The Scwariya granite, 'largest of the Erinpura granite intrusions' occurs along the western margin of the Middle-Late Proterozoic Soulh Delhi Fold Bell. Synkincmalic with the Delhi orogeny, the granite body intrudes a rifled back arc type basin (Barotiya Formation) and hosts W ± Sn ± Li mincralization in pneumatolytic quartz veins. Innumcrable metasedimentary enclaves occur which are traversed by syn-to post-tectonic ductile shear zones. Geochemistry of Ihe granite suggests it to be a well differntiated, calc-alkliline, S-typc metallogcnetically specialised orogenic massif. The nature of the granite and the host supracrustals and Ihe tectonic discriminant diagrams indicate that it may have evoled in an arc-related environment. W ± Sn ± Li mineralization in this granite, Pb-Zn-Cu and Zn-Cu mineralization in the contiguous units of Barotiya and Sendra formations respectively suggests a conspicuous metallogenic zoning.
The Sewariya granite forms a central link to the major Sn-W hosted granite rocks in Rajasthan Haryana sector that lie along a 500 km long NNE-SSW trending lineament. Although associated with felsic plutonic suites of contrasting geotectonic environments, W -Sn mineralizalion along this belt defines a single metallogenic province, a large part of which is unexplored.
Uranium Mineralisation in the South-Western Part of Cuddapah Basin: A Petromineralogical and Geochemical Study
Authors: Dhana Raju R. , Roy Minati , Roy Madhuparna , Vasudeva S. G. 
Published: November 2024

Abstract
Two types of uranium mineralisation occur in the south-western part of Cuddapah basin, viz., stratabound type hosted by impure dolostone of the Vempalle Formation of the Papaghni Group and structuralIy-controlled type hosted by deformed basement grani toid. The carbonate-hosted type occurs over a 140 km-long belt from Reddipalle in the west to Maddimadugu in the east with promising mineralisation at Tummalapalle, Rachakuntapalle and Gadankipalle. It is sandwiched between a Iower massive limestone and upper shale and cherty limestone. The rnineralised carbonate rock is a stromatolite-bearing 'siliceous, calcitic doIostone ' (SCD+phosphate) associated with other impure dolostones, quartzite, chert, phyllite, conglomerate, and intrusive dolerite a nd basalt. Uranium mineralisation occurs along the bedding plane, carbonate-phosphate conlact, micro-stylolites, grain boundaries of clasts and within pelioids, mainly in the form ultrafine pitchblende, in intimate association with pyrite and as disseminations in cellophane-rich parts, besides as minor phases ot'coffi~itea nd U-Ti compIex. The associated ore minerats include pyrite, molybdenite, chalcopyrite, bornite, digenite and covellite. The fertile basement granite fs.1.) is the source of uranium and the mineralisation, which appears to be polygenetic(syn-, dia- and epi-genetic), is controIled by impure nature of dotostone and organic activity. The mineralisation in the southern part of the belt in Cuddapa h district is typically molybdenum-rich, whereas the northern portion, in parts of Anantapur district, is characterised by high content of copper. The rnineralised SCD in the S/SE parts is also marked by high content of P, V and Pb, in addition to Mo. There is a good positive correlation of U with Pand V (r : 0.98 and more).
The structurally-controlled uranium mineralisation occurs around Rayachoti (outside the SW margin of Cuddapah basin) along a number of fracture zones within the basement granitoid, and is hosted by mylonites and cataclasites indicative of intense dislocation metamorphism. Of many such zones, the one between T. Sundupalle and Sanipaya is promising and has a strike extension of about 16 km. This mineralisation is epigenetic hydrothermal vein-type, mainly represented by coffinite, pitchblende, U-Ti. complex and secondary uranium minerals.
Some Geo-Technical Aspects of Meander Cutoff in Alluvial Environment
Authors: Chakraborty K. 
Published: November 2024

Abstract
The non-tidal Bhagirathi river, one of the most important waterways of West Bengal, India, displays picturesque meanders the behaviour of which appears to be random because of urpredictable bank-erosion. Thus an investigation has been made on some geo-technical aspects of the soil of the banks of the river. The results show that the nature of thc erosion of the banks which possess very closely similar soils, is difficult to explain only on the basis of the soil properties. It appears that the existing hydro-dynamic environment, its mega-or micro-Ievel changes and the soils of the banks are the key factors behind this bank-erosion.
Gold Mineralisation in the Precambrians (Bhukia Area) of Southeastern Rajasthan-A New Discovery
Authors: Grover A. K. , Verma R. G. 
Published: November 2024

Abstract
Several; ancient mines or old working exist in the vicinity of Bhukia village near Ghatol in Banswara district, Rajasthan, within Precambrian metamorphosed volcano-sedimentary rocks. These old workings/mines were earlier explored for base metals, specially for copper. Recent work carried out in this part indicated prcsence of native gold in visible form in some of the grab samples taken from two mine dumps. The maximum size of gold flake noticed is 4x2 mm. Higher gold values are generally associafed with high copper and arsenic values. This suggests re- examination of the ancient mines and certain lithounits present between Salumbar and Banswara, southeastern Rajasthan for gold.
Early Proterozoic Aravalli Metasediments and Their Relation with the Ahar River Granite Around Udaipur, Rajasthan
Authors: Guha D. B. , Garkhal R. S. 
Published: November 2024

Abstract
The Aravalli Supergroup around udaipur area, comprising volcano-sedimentary assemblage, is classified into three Groups, viz., the Delwara, the Debari and the Jharol Groups, based on two prominent horizons of conglomerate. The Lower Aravalli Delwara Group is separated from the Middle Aravalli Dcbari Group by a pronounced unconformity marked by a thick horizon of conglomerate exposed at Kabita which has heen correlated with the Debari conglomerate of the type locality. The Bari Lake volcanics are correlated with the Delwara volcanics and the quartzite-conglomerate occurring within the former are intertrappean in nature. The Ahar River Granite is identified as the post-Middle Aravalli intrusive granite, which intruded the Delwara volcanics and the Debari phyllite in comagmatic pulses of the same granitic magma.
LANDSAT Thematic Mapper Data Applied to Structural Studies of the Eastern Ghat Granulite Terrane in Part of Andhra Pradesh
Authors: Chetty T. R. K. , Murthy D. S. N. 
Published: November 2024

Abstract
LANDSAT TM data have been used as an aid to studying the regional geology of the granulite terrane in the southern part of Eastern Ghats. The technique in conjunction with regional traverses proved to be useful in identifying regional structural elements, such as shear zones, fold patterns of different scales and other lineament patterns, in poorly exposed and inaccessible areas. A major crustal scale ductile shear zone, designated as Sileru shear zone, with a dextral sense is highlighted and lies at the western margin of the high grade terrane. The other shear zones within the granulite terrane, characterised by migmatitic gneisses and typical L-S mylonitic fabrics, are associated with transpressional tectonics. Fold patterns varying from tight upright isoclinal folds to refolded large scale recumbent folds, along with complex fold interference structures on mesoscopic to regional scale are described. The interpretation of LANDSAT data, followed by limited ground based traverses from Sileru to Visakhapatnam in Visakhapatnam district and from Chinturu to Eleswaram in East Godavari district are the constraints in precisely defining the regional structures and understanding the tectonic processes that fashioned shear zones and fold patterns in granulite terranes. A fold thrust thin-skinned tectonic model involving two tectonothermal events for the study area is envisaged.
Occurrence of the Coral Reefs on the Bhandarpule Coast, District Ratnagiri, Maharashtra
Authors: Sukhtankar R. K. , Pandit S. J. , Shirke A. J. , Kulkarni S. A. 
Published: November 2024

Abstract
Development of living corals in the form of patch reefs has been recorded in the intertidal zone at Bhandarpule beach, District Ratnagiri, Mabarashtra. These are pink and reddish in colour and are composed of corals of the order of Stolonifera. These occur as a thin blanket on the hard substrate of volcanic breccia. Their occurrence in association with oyster bed and sea cave but at different elevations represents minor fluctuations of the sea level during the Holocene, associated with the Flandrian transgression.
Archaean Meta Lamprophyres from Nuggihalli Schist Belt, Hassan District - Karnataka
Authors: Sugavanam E. B. , Mallikarjuna C. , Vidyadharan K. T. 
Published: November 2024

Abstract
The Archaean Dharwar greenstone belts of Karnataka predominantly consist of iron enriched tholeiitic Metabasalts, basaltic komatiites, sulphidic chert bands and argillite-graywacke sequence. In Nuggihalli schist belt, in association with mafic-ultramafic rocks, calc-alkaline lamprophyres (Spessartite-Kersantite suite), comparable with Kamblada-Yilgam of Western Australia, have been recorded for the first time. Gold mineralisation is associated with these meta-lamprophyres.
The lamprophyres, in Nuggihalli belt, is a highly banded hornblende-biotite rich quartzo-felspathic rock, forming sill like bodies at the contact of mafic-ultramafic rocks, intensely co-folded along with the enclosing rocks, recording three phases of deformation.
REE values, plotted against MORB values confirm lamprophyric affinity with increased values for Sr, K, Rb, Zr and Y. In Rock/Chondrite values plot, very pronounced increase in values of Ba, Rb, K, P, Zr and Ti is indicated while a pronounced depletion in Nb is brought out, characteristic of Calc-alkaline lamprophyres.
Search for similar rocks in many ultramafic belts in Southern Peninsular Shield will be of great Significance in working out the tectonic evolution ofthese greenstone belts and also serve as favourable target areas for gold exploration.
Gravity and Magnetic Studies Over Parts of Khairagarh Basin, Central India
Authors: Rao R. L. N. , Srinivas R. , Sethuram S. , Subba Rao J. R. 
Published: November 2024

Abstract
Interpretation of gravity and magnetic data in a strip of 250 sq.km. over Lanji-Darekasa tract of Khairagarh basin has been attempted in order to delineate regional structures and controls of uranium mineralisation in the province. Magnetic map indicates three parallel east-west trending lineaments representing basic dykes cutting across the geologic fonnations. The orthogonally intersecting gravity and magnetic trends around Saheki (80° 31' : 21° 27' 30") reveal a tectonised zone favourable for uranium minelisation. Gravity low of the order of five milligals near Nimbanaka (21° 19' : 80° 31' ) suggests a sharp increase in the thickness of Bijli rhyolites.
Based on observed gravity, magnetic data and the available surface geological information, the paper proposes a model for configuration of Khairagarh basin along Lat. 21° 25' between Parsori and Khairagarh. Maximum thickness for volcano-sedimentary pile filling the basin along this section is estimated to be around 2300m. The model also indicates possibility for the presence of a concealed high density formation (Pitepani Volcanics?) below Bortalao sandstones.
Carbonic Metasomatism and Charnockitic Alteration
Authors: Santosh M. , Radhika U. P. 
Published: November 2024

Abstract
Field relations in an orthogneiss quarry within the Palghat Gap region illustrate the development of charnockite alteration halos surrounding alkaline pegmatite dykes. Altered orthopyroxenes in the charnockitic zones are artifacts from concordant melt pockets within the gneisses, where orthopyroxene has developed prior to the charnockitie alteration during regional metamorphic, in a process equivalent to dehydration melting. The charnockitic halos represent metasomatic alteration zones developed through the infiltration of CO2-H2O fluids expelled from the dykes at shallow crustal levels. Such examples of greasy green charnockitie alterations could be a widespread phenomenon in different crustal blocks of varying metamorphic grades, and are unrelated to regional prograde granulite processes.
Orbicular Rocks from Closepet Granite Near Hoskote, Tumkur Dt., Karnataka
Authors: Srikantia S. V. , Bhat P. G. K. , Subramani N. 
Published: November 2024

Abstract
The paper records the first occurrence of Orbicular rocks from the Closepet Granitoid belt near Hoskote, Tumkur district, Karnataka. The orbicules occur in a dioritic country rock enclosed within grey Closepet Granitoid. These are multishelled orbicules with shells of plagioclase and hornblende with a core of the same minerals. There are also proto-orbicules. The chemical analyses of orbicules fall in mafic tonalite field on K2O - CaO plots. Individual shells reflect a basic rock parentage. The orbicules are derived from a metabasic enclave due to granitic action by melting, diffusion and concretionary process in hydrous stage.
High-Temperature Reactions of Alkali and Plagioclase Feldspars With Alkali and Alkaline Earth Chlorides: Formation of Celsian
Authors: Swamy V. , Menon A. G. , Anantha Iyer G. V. 
Published: November 2024

Abstract
High-temperature reactions (Ca 900°C) involving albite, K-feldspar or plagioclase and K, Ba-or K, Sr chlorides were experimentally studied. These experiments reveal that the reaction between K-exchanged albite, potash feldspar, or plagioclase and Ba-chloride/Ba-K chloride results in the formation of celsian by the breakdown of the starting feldspar structure above 800°C. Sr-feldspar does not form under similar conditions. A size-effect of the large M-site cation appears to be responsible for the formation of celsian. The reaction between K-feldspar and barium chloride may be used as a method for synthesizing celsian.
The Crystalline Thrust Sheets in the Himachal Himalaya and the Age of Amphibolite Facies Metamorphism
Authors: Bhargava O. N. , Bassi U. K. 
Published: November 2024

Abstract
Three distinct crystalline thrust sheets exist in the Himachal Himalaya. These in ascending tectonic order of superposition are: (i) Kulu Thrust Sheet, (ii) Jutogh Thrust Sheet and (iii) Vaikrita Thrust Sheet. The crystalline thrust sheets show five deformations and polyphase metamorphism. The analysis of existing data suggests that there have been Precambrian deformations and attendant metamorphism. The Kulu and Vaikrita Thrust Sheets extend throughout the length of the Himalaya and the latter's equivalents consistently form the floor for the Tethyan sequences.
Roles of Relief and Climate on Composition of Detrital Sediments of Bharathapuzha Basin, Kerala
Authors: Anirudhan S. , Thiuvikramji K. P. , Roy Chacko P. T. 
Published: November 2024

Abstract
Channel sediments of Bharathapuzha (BP) basin provide an unique opportunity to examine the relative roles of climate and relief on the character of first cycle detritus derived from a source area of high grade metamorphic rocks, as the major tributaries of the river are set in diverse climatic domains. For e.g., Gayathripuzha (GP) and Thuthapuzha (TP) are in a tropical setting, while Kalpathipuzha (KP) enjoys a semi-arid climate. Sediments of a tropical-, low relief stream, the Tirur river (TR) lying adjacent to Bharathapuzha (BP) in the north, have also been examined.
The average mineralogical maturity of sands expressed as Q:F:R ratio, for the mainstream of BP varies from 72:19:9 for coarse to 53:38:9 for medium sand and to 49:44:7 for fine sand, implying an arkosic composition. The Q:F:R ratios of GP and TP, the two high relief tributaries on the one hand and of KP, the low relief trib utai) on the other are similar to that of mainstream of BP basin. However, quartz arenite (Q:F:R = 93:5:2) is under transport in the tropical-low relief, Tirur river (TR).
The chemical maturity index (CMI), i.e. the ratio of SiO2/Al2O3, for the sediments of main stream (7.27) and for the tributaries, amply demonstrates the immaturity of the channel sediments. Nevertheless a value 120, for Tirur river sands indicates their super maturity.
Effect of River Discharge on the Morphology of Benthic Foraminiferal Test
Authors: Nigam Rajiv , Khare Neloy 
Published: November 2024

Abstract
Twenty one surface sediment samples collected from the inner shelf region off Karwar at 22-52 m water depth range have been studied for foraminiferal content. Based on the external test morphology the entire foraminiferal population (148 species) can be placed into two broad morpho-groups namely angular-asymmetrical and rounded-symmetrical morpho-groups. The surficial distribution of these groups revealed that angular-asymmetrical morpho-group gets adversely affected by high turbulence associated with increased fresh water river disCharge, whereas, rounded-symmetrical morpho-group responded in a reverse manner. Since areal extent of river induced turbulence depends upon fresh water discharge due to monsoonal rains, the results show high potential in generating proxy data for the reconstruction of paleomonsoonal history through the study of morpho-groups in sub surface sediments of coastal regions.
Magma Fractionation and Mixing in Nephelinite Plug Associated with Deccan Magmatism at Murud-Janjira, South of Bombay, India
Authors: Dessai A. G. 
Published: November 2024

Abstract
The nephelinite occurs as a N-S trending plug (500 × 200 m.) intrusive into basalts. The rock is porphyritic and principally composed of complexly zoned phenocrysts of clinopyroxene, Fe-Ti oxide and olivine &lt;5%) in a fine grained groundmass dominated by clinopyroxene, nepheline and Fe-Ti oxides. Mineralogically and chemically the rocks vary between pyroxene melanephelinites and nephelinites.
The mineral chemistry implies that the magma has undergone varying degrees of polybaric crystallisation in a subcrustal magma chamber with mixing of more fractionated magma with primitive pulses in which are incorporated disaggregated mantle xenolith phases.
Ore Mineralogy of Western Auriferous Zone of Gadag Greenstone Belt, Karnataka
Authors: Ugarkar A. G. , Devaraju T. C. 
Published: November 2024

Abstract
Gadag greenstone belt, which has a history of ancient gold mining, hosts three distinct auriferous zones viz., Western Zone, Middle Zone and Eastern Zone distributed both in metavolcanic and metasedimentary suites. The paper presents ore mineralogy of the Western Auriferous Zone which is hosted by pillowed and sheared metavolcanic rocks. Based on the relative abundance of quartz veins and sulphide minerals this zone could be classified into Type-A ore and Type-B ore.
Type-A ore comprises white quartz veins (30-90 cms thick) displaying evidence of early deformations. They contain chloritic/micaceous leafy aggregates and traces of arsenopyrite, pyrite, chalcopyrite and sphalerite ± scheelite; gold occurs in native form in vein quartz.
Type-B ore comprises mainly chlorite-muscovite/sericite-ankerite-monazite sulphide schist with subordinate vein quartz. Associated sulphides are arsenopyrite, pyrite, pyrrhotite, chalcopyrite, sphalerite and galena in the orderof decreasing abundance. Scheelite is seen occasionally. Gold occurs as: (i) native gold in silicate and quartz gangue, (ii) native gold inclusions and microfracture fillings in arsenopyrite and (iii) in combined state in arsenopyrite. Arsenopyrite could serve as a main pathfinder mineral for exploration, mining as well as processing of Type-B ore.
Mineralogical characteristics, wall-rock alterations and structural features related to Type-A ore, Type-B ore and host rocks characterise the gold mineralisation in the Western Auriferous Zone as structure controlled hydrothermal epigenetic lode.