bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gold Mineralisation in Kappil Prospect, Malappuram District, Kerala
Authors: Nair R. S. , Suresh Chandran M. 
Published: November 2024

Abstract
A preliminary appraisal of gold mineralisation at Kappil indicates its association with quartz veins traversing the Archaean metamorphic complex comprising biotite-hornblende gneiss, quartz-magnetite granulite (QMG) and amphibolite. Gold mineralisation is confined to the highly sheared and fractured quartz veins/QMG carrying stringers and rich disseminations of pyrrhotite, pyrite, chalcopyrite and arsenopyrite. The visible native gold is distributed along fracture planes in quartzose portion and also as fine disseminations in pyrrhotite, pyrite and arsenopyrite indicating its introduction along with sulphide mineralisation.
The major element geochemistry on drill core samples has indicated a tholeiitic affinity for the amphibolite and a mixed pelitic and arkosic parentage for the biotite-hornblende gneiss. Trace element studies have shown sympathetic relationship of Au with Cu.
Five lensoid gold-bearing lode zones a re distributed along shear zones trending in a N-S direction. In the initial stages gold was syngenetically deposited with sulphide-bearing magnetite quartzite (now QMG), later, remobilisation and redistribution have caused enrichment and deposition of gold along shear zones. Post-magmatic processes are considered responsible for the localisation of gold and metal sulphides.
Petrochemistry and Tectonic Setting of the Champawat Granite Suite of Lesser Himalaya, Pithoragarh District Uttar Pradesh
Authors: Hussain Shabbir , Raju S. , Dayal B. , Fareeduddin  
Published: November 2024

Abstract
The concordantly emplaced polyphase granite suite exposed in the Champawat area of Pithoragarh district of Uttar Pradesh represents a part of the southernmost granitoid belt of Himalayan region. In the field it can be divided into four successive mappable phases, viz. biotite granite, grey granite, leucogranite and microgranite. Mineralogically the biotite granite and grey granite are classified as "granodiorite" while the leucogranite and microgranite are classified as "granite". All these varieties of granite show xenoliths of country rocks. Champawat granite suite is a well differentiated, polyphase, calc-alkaline, peraluminous, S-type granitoid batholith that ranges in composition from granite to granodiorite- adamellite and trondhjemite. It is interpreted to be the product of anatexis of supracrustals at middle to lower crustal levels. The geochemical discriminant diagrams of the Champawat granite suite suggest that it is an orogenic granite showing characters of continental collision environment.
Influence of Geology on the Localization of Ancient Caves
Authors: Deshmukh Megha 
Published: November 2024

Abstract
Of the 1545 caves in India, more than 1200 caves are located in the region of Deccan Trap in Maharashtra State. The reconnaissance survey of these caves demonstrated that more than 1000 caves are concentrated in the area made up of amygdaloidal basalts, as they provide suitable medium for carving. In contrast to this, in the region of compact basalts, which do not provide homogeneous medium for carving due to their jointed nature, the cave centres are few and far between. This clearly indicates that the carving activity in the Deccan Trap region was influenced by the geological factors and not by trade routes as is commonly believed.
North Gujarat Rivers: Remnants of a Super Fluvial System
Authors: Sridhar V. , Merh S. S. 
Published: November 2024

Abstract
A thickness of over 300 m of dominantly alluvial sediments in the north Gujarat plains suggest that the sedimentation took place during the late Quaternary period in a huge graben bounded by faults that are related to the Cambay basin. An ancient super fluvial system was responsible for this vast accumulation. Most of the present day rivers are the remnants of that former system and have exposed the sediments in cliff sections. The present course of the Sabarmati appears to be unrelated to the former system for much of its length. Its course is controlled by a major lineament that developed subsequent to the deposition of the entire sequence. The earlier course of the river is now represented by the river Rupen. The uplift of the Aravallis during the Mid-Late Quaternary and the eustatic sea level changes might have disrupted the older system.
Spinifex-Textured Peridotitic Komatiite from Honnabetta Area, Nagamangala schist Belt, Karnataka
Authors: Devapriyan G. V . , Ananthar T. R. , Vidyadhar K. T. , Raghu Nandan K. R. 
Published: November 2024

Abstract
Metaultramafite exposure in the newly cut Hemavathi canal section in Honnnbetta area in the Nagamangala belt exhibits excellent spinifex texture with komaliitic chemistry implying their volcanic origin. Though, several such localities of spinifex textured peridotitic komaliitcs (STPKs) have already been recorded from Ghattihosahalli, Kummanghatta, Banasandra, Mayasandra and Karighatta areas, this new find of plate and random spinifex textured ultmmafic variant from Honnabetta is the first report from the Nagamangala belt. They show yellowish green colour with skeletal forms of olivine blades, which are totally altered to talc-tremolite-chlorite, anthophyllite, iddingsite and antigorite. Parallel sheafs and aggregates of bladed olivine pseudomorphs form plate spinifex with criss crossing random orientation pattern. The primary igneous mineralogy consists of altered relict olivine and clinopyroxene phenocrysts. A few samples exhibit micro-spinifex texture with randomly oriented, elongated platy, pseudomorphs of olivine separated by tremolite in the groundmass. Gradational change from fine to coarse-grained spinifex with long crystals (rare) of clinopyroxene in a fine-gained groundmass of tremolite and chloriteis also observed. Medium-grained spinifex rockshow crystals upto 5 to 2 mm thick and 10 to 50 mm long in sheafs with parallel grouping and abut against each other randomly at angles varying from 40 to 60° enclosing triangular to rectangular interstitial talc, chforitc, pale green finegrained chlorite and glassy material. Ilmenite-magnetite and chrornite are the important accessory opaque minerals, with ilrnenite at places showing oriented picotite inclusions. Normative plots indicate that the STPKs of Honnabetta are hurzburgitic peridotites.
Compared to the Ghattihosahalli-Kummanghatta and Banasandra STPKs, tlonnabella STPKs show characteristic plate and random spinifex texture. In texture they are similar to Karighatta STPKs and in composition they compare well with Mayasandra STPKs with their low CaO:Al2O3 ratios. lnspite of alteration (hydration), deformation and metamorphism, preservation of primary igneous structures and textures is almost perfect in Honnabetta. Such a zone with a possible thermal erosion model for the Komatiitic types imply some sulphide bodies at depth, as incidence of sulphide associated with gold minerrrlisation arc observed in Honnabetta area.
P-T Conditions of Metamorphism and Fluid Inclusion Characteristics of the Coorg Granulites, Karnataka
Authors: Srikantappa C. , Venugopal L. , Devaraju J. , Basavalingu B. 
Published: November 2024

Abstract
Charnockites and basic granulites occur extensively around Coorg in Western Ghats. Minor metasedimentary rocks like kyanite/sillimanite bearing gneisses and ironstone also occur. A set of late dolerite dykes cross cut all the lithologies.
The Coorg granulites record a near-peak metamorphic conditions of 720 to 760° C at pressures of 7 lo 8.6 kb. Charnockites and basic granulites contain high-density ( 1.07 to 1.09 g/cc) carbonic inclusions. Micro-textures, mineral P-T and fluid inclusion data indicate "clockwise" P-T trajectory, pointing to a relatively rapid uplift/erosion of the Coorg granulites.
Garnet-Kyanite Bearing Pelitic and Associated Mafic Granulites along Jalsoor-Mercara Shear Zone: Evidence for Deep Burial and Later Uplift
Authors: Krishnaraj N. S. , Janardhan A. S. , Basavalingu B. 
Published: November 2024

Abstract
Garnet-kyanite-sillimanite bearing pelitic and garnetiferous mafic granulites exposed at several places along the Jalsoor-Mercara and Bavali shear zones preserve evidences of deep burial of atleast 30 km. Estimation of P-T conditions of metamorphism of these granulites gives T of 725-800°C and P of 7 to 8.6 kb. Increase of pressure form core to rim in the garnet-kyanite assemblages and kyanite mantling garnet are the most significant aspects of these lithologies, suggesting long residence in the deep crust and possible thrust tectonics.
Moreover, fibrolitic sillimanite overgrowing kyanite in pelites and the developement of opx-calcic plag symplectites around garnet in the mafic rocks indicate decompression/uplift, subsequent to crustal thickening. This uplift could be part of a later event unrelated to the burial episode.
Significantly, syenite and anorthosite bodies of late Proterozoic age occur along these shear zones indicating that these lineaments were reactivated again in late Proterozoic times.
Grain Growth Parameters and Mineral Zoning: A Comparative Study from the Humboldt Mountains, East Antarctica
Authors: Pant N. C. , Verma P. K. 
Published: November 2024

Abstract
Certain aspects of regional metamorphism of East Antarctica granulite terrain in the Humboldt Mountains are revealed through a study of the grain size of garnets and chemical zoning present in them. The Ferry and Cashman approach to grain size (Crystal size Distribution-CSD) development and Walther and Wood approach of grain growth are utilised to draw intersting conclusions. The growth of garnets was slower in the deeper levels but produced large, chemically unzoned grains.
Palynology of Carbonaceous Clays of Nimar Formation, Jhabua District, Madhya Pradesh, India
Authors: Kumar Pramod 
Published: November 2024

Abstract
Carbonaceous clays of Nimar Formation, exposed near Umrali village in Jhabua District, Madhya Pradesh have been palynologically analysed. The palynoflora dominated by the pollen of conifers compares favourably with Jabalpur, Rajmahal, Vemavaram/Raghavapuram and Bhuj palynoassemblages. Due to nonavailability of Early Cretaceous palynofossils, the assemblage is dated as Late Jurassic.
The palynoflora points towards prevalence of fresh water, warm humid, swampy conditions during the deposition of the Carbonaceous clays of Nimar Formation.
A Study of Hogbomite in the V-Ti-Fe Deposits of Karnataka
Authors: Jayaraj K. R. , Khanadali S. D. , Devaraju T. C. , Spiering B. 
Published: November 2024

Abstract
Hogbomite is of widespread occurrence as an accessory and minor mineral in the V-Ti-Fe ore deposits of Ubrani, Tavarekere, Masanikere, Magyatahalli and Devaranarsipur in Shimoga district and Mulemane in Uttar Kannada district. Both primary and secondary hogbomite are found. The mineral shows considerable variation in chemistry. The analytical data indicate that hogbomite structure is relatively more open than that of coexisting magnetite/ilmenite and can admit a variety of substitutions.
Hummocky Cross-Stratification in Barakar Formation, Ramgarh Coalfield, Bihar
Authors: Gupta Abir 
Published: November 2024

Abstract
Sequence of moderately sorted siltstone to coarse grained sandstone containing abundant hummocky cross-stratified and swaley cross-stratified bedding has been described from five stratigraphic levels in a part of Barakar Formation, along the Damodar river, Ramgarh coalfield, Bihar. Scour and drape type and non-erosional based growing bed-forms, both types of hummocky crossstratification have been observed. The large dimension of hummocks, upsweeping of laminae, sigmoidal nature, broadly undulating erosive and flat base, draping and also the presence of tide influenced associated sedimentary structures, high sulphur and phosphorous content in the coal seams, high vitrinite content in the coal, absence of fining upward sequence, clay mineralogy, high concentration of chromium, similarities in trace element content with that of Assam coalfieds and presence of marine microfossils probably indicate that the observed part of Barakar Formation were deposited in an estuarine to marginal marine environment, Water depth was probably of the order of 1-30 m.
Precambrian Bimodal Volcanism in Weddell Sea, West Antarctica
Authors: Divakara Rao V. 
Published: November 2024

Abstract
Rhyolites and basalts constitute bulk of the bimodal volcanism in the Bertrab and Littlewood nunataks of Weddell Sea area, western Antarctica. Rhyolites with occasional granophyres from the two nunataks are compositionally similar except for high Ba in Littlewood. Basalts, of tholeiitic to calc-alkaline nature are mainly from the Bertrab nunatak and show compositional variation (basalt to basaltic-trachy-andesite) both in major (SiO2, 45.82 to 53.81%, MgO, 4.67% to 11.20% Na2O, 1.58 to 4.26%) and trace elements (V, Cr, Rb, Sr and Ba). The rare earth elemental abundances and their distribution patterns in the rhyolites from the two nunataks are broadly similar with comparable total REE (Bertrab 80.33; Littlewood 86.82), moderate LREE/HREE fractionation (CeN/YbN= 4.36 in Bertrab and 4.33 in Littlewood) and negative europium anomdies.
Overall major and trace elemental chemistry of the acid volcanics coupled with the systematic compositional variation from the basic to the acid end suggests a common source of origin for this bimodal volcanism. The source magma, a melt of the upper mantle appears to have evolved in a compressional tectonic regime and has intruded (extruded) in an extensional rift tectonic setting.
Marine Magnetic Studies Over a Lost Wellhead in Palk Bay, Cauvery Basin, India
Authors: Ramana M. V. , Subrahmanyam V. , Sarma K. V. L. N. S. , Seshavataram B. T. V. 
Published: November 2024

Abstract
Close grid masine magnetic surveys in the vicinity of a drill well site PH 9-1 in Palk Ray revealed that the area is characterized by smooth magnetic field except for a local anomaly caused by a lost wellhead. The smooth magnetic field is attributed to the deep burial of Precambrian granitic basement devoid of any charnockite intrusions. The seismic reflection records of the study area show &gt;3200 m thick sediments over the basement.
Petrography, Geochemistry and Petrogenesis of Alkali Lamprophyres of Jungel Suite, Central India
Authors: Kumar Vinod 
Published: November 2024

Abstract
A systematic petrographic and geochemical study of three, previously unreported carnptonite dykes from Bijawar of Son valley is presented with a brief discussion on their petrogenesis. These larnprophyres show transition from alkali basalt and owe their origin through fractionation combined with local enrichment of volatiles, largely derived from mantle instead either by hybridization or assimiIation of basic magma with granite/late stage granitic fluids or mixing with an andesitic magrna as proposed by some earlier workers.
Retrieval of the trace of the true axial surface on an oblique section through a fold
Authors: Choudhuri Anjan Rai 
Published: November 2024

Abstract
On an oblique section, the line connecting the points of maximum curvature of the bounding surfaces of folded layers may not coincide with the trace of the actual axial surface. Methods have been suggested for construction of the true axial trace on an oblique section.
Cretaceous and Middle Eocene Radiolaria from Ejected Sediments of mud Volcanoes of Baratang Island in Andaman Sea of the Northeastern Indian Ocean
Authors: Ling Hsin Yi , Sharma V. , Singh Surender , Mazumdar D. , Mahapatra A. K. 
Published: November 2024

Abstract
Radiolarians from seven samples of ejected sediments of mud volcanoes of Baratang Island in the Andaman Sea provide additional evidence for the presence of Cretaceousand MiddIe Eocene strata beneath the island. A general NNE-SSW alignment of the mud volcanoes suggests the structural control for their occurrence due to regional tectonics.
Mineralogy and Geochemistry Of Detrital Magnetites from the Beach Sands of Cox's Bazar, Bangladesh and their Petrogenetic Implications
Authors: Mitra Sachinath , Ahmed Syed Samsuddin 
Published: November 2024

Abstract
Ti-poor magnetites from Cox's Bazar beach are seen to be remarkably homogeneous, chemically and optically, containingless than 2% uIvospinel. Mg, Ti, Cr, A1 and V, though in insignificant amounts, are found to be responsible in contributing to the reduction in hyperfine field of the Mossbauer spectrum, which showed linewidths of 0.18 mm/s at B-site and 0.26mm/s at A-site. Certain fraction of these magnetites manifests authigenic growth, presumably in a locally reduced condition. Intergrowth of ilmenite with titanomagnetites possibly resulted from oxidation of ulvospinel-magnetite and a regular partitioning of Cr, V, AI, Mg and Mn observed between coexisting titanomagnetite and ilmenite suggests a chemical equilibrium. The temperature and oxygen fugacity of coexisting titanomagnetite-ilmenite phases as calculated ranged from 625-850°C and 10-15 to 10-21 respectively. These temperatures and oxygen fugacities equilibrated in a T-fO2, field very near to FMQ (Fayalite-Magnetite-Quartz) buffer curve, lending support to its genesis in the upper crust, more being of igneous sources rather than metamorphic.
Granitoid Rocks of Wangtu Gneissic Complex, Himachal Pradesh: An Example of In situ Fractional Crystallisation and Volatile Action
Authors: Rameshwar Rao D. , Sharma Kewal K. , Gopalan K. 
Published: November 2024

Abstract
The Wangtu Gneissic Complex (WGC) of Himachal Himalaya represents the basement rocks which remained more or less in its original realm. The unique feature of this complex is that the various phases of deformed and undeformed granitoids are exposed in the area. The complex has a peripheral zone of augen gneisses and core of non-foliated granitoids comprising of Coarse Porphyritic Granites (CPG) and Fine Grained Granites (FGG).
In the field the FGG rocks have sharp intrusive contacts with CPG rocks. At places they are entrapped or have protrusions into CPG rocks. Compositionally they represent syenogranites. They are peraluminous to meta-aluminous with Sr initial ratio of 0.705. The major and trace elements of these rocks show unimodal distribution pattern on different variation diagrams. They along with rare earth elements show marked fractionation trends, with a significant negative Eu anomaly. The rocks more or less define an isochron, representing Rb-Sr age of 1895±64 Ma.
The petrochemical studies favour a fractionated rather than multiple intrusions of magma. The studies suggest that fractional crystallisation of parental magma gave rise to early formed CPG rocks and the residual melts resulted in the crystallisation of FGG rocks. The last formed granitoids, the FGG rocks are interpreted as the final residue which crystallised rapidly after build-up and loss of fluids and volatiles which migrated to higher levels to form pegmatite phase in the aureol zone. The Rb-Sr systematics in the present case indicate that the granite have primary crystallisation melts derived from the deep crustal levels around 1895±64 Ma.
Factor Model for the Genesis of Manganese Deposit, Balaghat, M.P.
Authors: Nayak B. K. , Acharya B. C. , Sahoo R. K. 
Published: November 2024

Abstract
Complex system of geochemical variables obtained from manganese ores of Balaghat mine, M.P., is simplified by using R-mode factor analysis of correlation matrix. Eighteen major oxides and trace elemental variable have been expressed in terms of the three common (rotated) factors and genetic interpretations of these factors have been brought out in relation to the manganese deposit.
Geochemistry and Rb-Sr Chronology of Upper Jurassic A-type Granite, Tangmarg region, Kashmir Himalaya
Authors: Rameshwar Rao D. , Sharma Kewal K. , Gopalan K. 
Published: November 2024

Abstract
The present paper deals with petrochemistry and geochronology of granite pluton that intrudes the Agglomerate Slate-Panjal Trap sequence in Tangmarg region of Baramulla district, Kashmir Himalaya. This granite body henceforth called 'Tangmarg Granite' contains biotite, amphibole and rare pyroxene as mafic minerals and shows higher abundances of Zr, Nb, Ga, Y and REE, and lower AI, Mg and Ca contents. The geochemical signatures suggest the granite to be chemically distiIict from most of the orogenic granites (M-, I- and S-types) and points to their Anorogenic nature.
The six point whole rock Rb-Sr isochron of the Tangmarg granite gives an age of 161 ± 5 Ma, with Sr ratio of 0.714. The small size of the pluton points to limited melt generated from a partial fusion 'event' of short duration. Such a melt is attributed to pressure release due to reactivation of the faults that were formed during Permo-Triassicrifting event.
Petrographic and Facies Evaluation of Middle Siwalik Subgroup of Jammu, Himalaya
Authors: Pandita S. K. , Bhat G. M. 
Published: November 2024

Abstract
This paper embodies the results on the study of depositional environment, provenance and tectonic setting of Middle Siwalik Subgroup of Jammu region. The data obtained on lithofacies, sedimentary structures and nature of contacts between various lithofacies, suggest multiple episodes of avulsion and abandonment of the channel system for a new course in braided river system. Four variable plot of quartz types shows that these sediments have been derived from low rank metamorphic source. The detrital modes (quartz, feldspar and lithic fragments) plotted on complementary ternary diagrams (QFL and QmFLt) indicate that these sediments have been shed from recycled orogens, transitional arc and transitional continental provinces.
Quaternary Facies and Palaeoenvironment in North and East of Sambhar Lake, Rajasthan
Authors: Sundaram R. M. , Pareek Suresh 
Published: November 2024

Abstract
Quaternary landforms in the northern and eastern proximity of the Sambhar lake in Rajasthan are products of depositional, structural and erosional processes. The depositional landforms are made up of four fluvial and two each lacustrine and aeolian facies. The structural and erosional landforms are carved out of Precambrian hard rocks. Each of the four fluvial facies essentially comprises a sequence of upward fining sediments characterised by a pedogenic cap except for the youngest one viz. laterocalcrete, calcrete and brown loamy soil. Amongst the two lacustrine facies, the older is marked by the presence of saline deposits and the younger by saliferous sediments. Of the two aeolian facies, the older is represented by longitudinal dunes, undulatory mounds and sandsheets while the younger by barchans and obstacle dunes. The depositional facies have evolved in a sequence which indicate subtle variations in a predominantly arid climate. The presence of fluvial sediments forming the lake base contradicts the earlier observation which suggested an aeolian base for these lacustrine sediments.
Ductile Shear Zone Between Shantinagar-Uppalchelka in Khammam District, Andhra Pradesh
Authors: Mukhopadhyay Indrani , Ray ]yotisankar , Nath Sudipto 
Published: November 2024

Abstract
This paper describes the results of field investigation and structural geology of the rocks of the area between Shantinagar - Uppalchelka in Khammam district of Andhra Pradesh (latitudes 17°14'15" to 17°18'43" N and longitudes 80°41'40".to 80°44'44" E). A zone of silicification (quartz - mylonite with well preserved colour banding) with patches of tectonic conglomerate (quartz-pebble) is found to occur within the generally dominant amphibolites. Structural analysis indicates the dominant influence offolding deformation (plungeoffold axis 42° -&gt; 74°) in the area. All microstructural elements (e.g. polygonization, subgrain formation, "core-mantle" structure, ribbon like appearance of quartz grains) are deduced to be related to ductile deformation, recovery phenomena and recrystallisation process. Progressive development of tectonic conglomerate fabric and decrease in grain size are typically indicative of incremental strain magnitude across shear zone in the studied area. A "thin skinned" tectonic model invoking a network of thrusts has been proposed.