bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and Evolution of a Prograding Reservoir Delta in the Damodar River, India
Authors: Ray Pulak K. 
Published: November 2024

Abstract
The Damodar River is an ephemeral river with a braided stream pattern in many sections during the flood stage. Flood discharge is concentrated during summer monsoons. Damming of this river has produced two deltas, one corresponding to the live storage level ('upper delta') and the other at flood storage level ('lower delta'). The progradation of the upper delta over the topset beds of the lower delta coupled with fluctuations in lake level has produced a cyclic progradational deltaic sequence in the reservoir.
A significant zoning of the sedimentary structures is observed in the different parts of the delta. Parallel lamination is the major structure in the bottomset area; cross-stratification, ripple drift lamination and deformational structures predominate the foreset area; and horizotal and cross-stratification charactcrize the topset area. Cyclic sedimentation units with their characteristic sedimentary structures and grain size arc also characteristic of the topset area. The alluvial valley section is dominated by multiple units of a variety of cross-stratifications and some upper flow regime flat beds.
Ferroan Ankerite from the Chiknayakanhalli Schist Belt, Karnataka
Authors: Devaraju T. C. , Anantha Murthy K. S. 
Published: November 2024

Abstract
Mineralogy of ferroan ankerite with the composition (Fe, Mn)0.67 (Mg)0.38 (Ca)0.93 C2O6 is discussed with the aid of X-ray, DTA, and chemical data. The mineral typically occurs in the iron-enriched carbonate bands, which are either closely associated or enclosed within the iron formation. Available evidence suggests syngenetic chemical sedimentary origin for the mineral.
Anorthositic Enclaves in the Gneisses Around Holenarasipur Schist Belt, Hassan District, Karnataka
Authors: Hussain S. M. , Ahmad S. M. 
Published: November 2024

Abstract
Two occurrences of anorthosite enclaves in the 3.4 b.y. old gneisses surrounding the Holenarasipur schist belt are reported. The Mandagere enclave has An92 whereas, Arkalgud enclave has An83. Both the bodies are metamorphosed to higher amphibolite facies and exhibit granoblastic texture. They are associated with ultramafic enclaves. These occurrences along with the lunar type anorthosites of Holenarasipur Group greenstone belts are significant in early crustal evolution models.
Paleohydrology of Permian Gondwana Streams in Bokaro Basin, Bihar
Authors: Casshyap Satyendra M. , Khan Zahid A. 
Published: November 2024

Abstract
The clastic assemblage of Lower Permian Karharbari (70 m thick) and Barakar (800 m thick) Formations of the East Bokaro Basin shows a progressive upward decrease in grain size and scale of cross-bedding, illustrating a fining upward mega-cycle. A paleo-flow analysis reveals that the Gondwana sediments were deposited by streams which flowed towards north-northwest. The azimuthal variability is 2240 for Karharbari, 3304 for Lower Barakar and 4429 for Upper Barakar. Empirical relationships from modern streams are used to estimate various channel morphological and hydraulic attributes of ancient Karharbari and Barakar streams. Results indicate a progressive decrease in channel width and depth, channel slope. flow velocity and Froude number, with consequent increase in sediment load parameter, channel sinuosity for the Gondwana streams. as sedimentation continued from Karharbari through Lower to Upper Barakar. It is suggested that amelioration of climate through time possibly had a great control on river metamorphosis and sedimentation than tectonism.
Study of Beach Sand Movement by Fluorescent Tracer at Coondapur, S. Kanara District, Karnataka
Authors: Venkatesh K. V. 
Published: November 2024

Abstract
Three fluorescent tracer tests were carried out in the swash zone on a strip of the beach, south of Ganguli light house. An analysis of the tracer dispersion pattern reveals that generally the predominant vector of sand movement is along shore in a southerly direction. The grain velocity varies from 0.7 to 1.23m/min. It is observed to be higher in the finer sized grains than in the coarse grains. The computed rate of sand depletion for the first ten minutes is 1.99 kg/min. The result of the size analysis data shows that the sand grains tend to undergo differential motion with the coarser sized ones moving towards the shore and the finer ones seawards.
Geochemistry of Some Thermal and Cold Waters of Godavari Valley
Authors: Saxena V. K. , Gupta Mohan L. 
Published: November 2024

Abstract
Results of chemical analyses of fifteen thermal and cold waters of Godavari valley are reported. Agnigundala (Bhadrachalam) thermal water is of Na-Cl type and the rest are of Na-Ca-HCO3-SO4 type. It is likely that the Agnigundala geothermal system is associated with Archaean gneisses and is characterised with a reservoir temperature around 170°C. Other warm waters of the valley show low concentrations of dissolved solids and are similar to those which are associated with sedimentary rocks. It appears that the groundwater after movement to appropriate shallow depth, got heated up to moderate temperature (around 80-90°C). Thereby the basic chemical character of the water has not changed much due to movement, both downward and upward, through the same type of rocks.
A Note on the Burial Diagenesis of Clay Minerals in the Bengal Fan
Authors: Dilli Kailas , Rao C. N. 
Published: November 2024

Abstract
A thick (770m) pelitic section ranging in age from Quaternary to Middle Miocene encountered at the DSDP site 218 in the Bengal Fan has been investigated for the burial diagenesis of clay minerals based on x-ray diffractometry and partial chemical analysis. The clay minerals are dominated by illite, with minor amounts of montmorillonite, chlorite and kaolinite. All the clay minerals are descrete and detrital derived from the Himalayan hinterland. The clay mineral transformations are largely confined to compaction attendant on the escape of pore water and adsorption of K and Mg in the interlayer positions resulting in better organised illite, montmorillonite-illite and montmorillonite-chlorite mixed layers at depth. The sediments are considered to be in the early diagenetic stage of Dunoyer de Segonzac (1970).
Physical Conditions of Metamorphism of Calc-Silicate: Rocks from Koduru-Garividi, Andhra Pradesh
Authors: Sivaprakash C. 
Published: November 2024

Abstract
Calc-silicate rocks with the assemblage calcite + K feldspar + quartz + wollastonite + diopsidess + scapolite + sphene ± grossular-andradite ± hornblende ± magnetite ± zoisite occur associated with metasedimentary manganese deposits at Garividi in Vijayanagaram district of Andhra Pradesh. From the mineral assemblages the temperature, pressure and composition of an ideally mixed H2O-CO2fluid phase during metamorphism have been derived for the following mineral reactions:
Calcite + Quartz = Wollastonite + CO2.
Grossular + Quartz = Anorthite + Wollastonite.
Tremolite + 3 Calcite + 2 Quartz = 5 Diopside + 3 CO2 + H2O.
For the analysed mineral compositions temperatures of the order of 700 ± 50°C and pressures of 7 ± 1 kb have been estimated. Mole fraction of H2O dnring metamorphism was at least 0.6. Fluid compositions appear to have been internally buffered during metamorphism.
A Regional Tectonic Study of the Archaean Chitradurga Greenstone Belt, Karnataka, Based on Landsat Interpretation
Authors: Drury S. A. 
Published: November 2024

Abstract
The usefulness of LANDSAT images, both photographic and digitally processed, for reconnaissance structural studies is demonstrated. To a certain extent lithological discrimination is possible by these techniques, but stratigraphic interpretation is impossible other than in conjunction with detailed field studies of structure and way-up indications.
The tectonic boundary between the two cratonic sub-blocks of eastern and western Karnataka, identified by deep seismic sounding and recognised in a few places by field studies is delineated, as are other major faults. Major Archaean fold forms in the greenstone and gneisses are traced throughout the belt and interpreted as westward verging lobes of basement separated by synclinal cusps of greenstone belt cover, which have been disrupted and further deformed by smaller NNE-SSW folds and the major fault lineaments. Varying crustal level within this sequence of lobes and cusps is suggested to explain the variable state of deformation and metamorphism of greenstones in the craton, and N-S shear zones in the gneisses are thought to be expressions of shear strains beneath eroded cusps.
Pressure-temperature Estimates of the Basic Granulites and Conditions of Metamorphism in Sargur Terrain, Southern Karnataka and Adjoining Areas
Authors: Janardhan A. S. , Gopalakrishna D. 
Published: November 2024

Abstract
Chemistry of co-existing mineral pairs of opx-cpx ; opx-gt and cpx-gt from several metabasic rocks consisting of two pyroxene assemblages and recrystallised ultramafics from Hullahalli and Dodkanya of Sargur terrain and Sathyamangalam, along with data taken from recent literature are utilized to estimate the Pressure-Temperature conditions of metamorphism. Temperature estimates are around 767±50°C and average pressures of 8-9 kbs indicate the peak of metamorphism which operated in the Sargur terrain. This suggests a crustal thickness of 30-35 krn, which was attained prior to the onset of granulite facies metamorphism.
Geology of the Gurgunta Schist Belt, Raichur District, Karnataka
Authors: Narasimha S. , Hans S. K. 
Published: November 2024

Abstract
Equivalents of Sargur Group of rocks are recognised for the first time in northern parts of Karnataka. In the area northwest of Hutti, Raichur district, medium to high grade metamorphic rocks namely, amphibolite, banded ironstone (amphibole-magnetite- bearing chert), meta-sediments (fuchsite quartzite and sillimanite-bearing pelites) and meta-ultrabasics, occur as a linear belt and as isolated enclaves in Peninsular gneiss. The name' Gurgunta Schist Belt' has been given in order to distinguish it from the Hutti Schist Belt. Alkali granites and dolerite dykes are younger intrusives. The gneiss and the enclaves have suffered three phases of folding deformation giving rise to the present outcrop pattern of an oval shaped dome. Faults post date the folding events in the area.
Palyno-Stratigraphy of the Lower Gondwana Rocks of Darjeeling, Eastern Himalaya, India
Authors: Ghosh T. K. 
Published: November 2024

Abstract
In the course of systematic palynological investigation of the Lower Gondwana (Permian) coals from Darjeeling district, West Bengal, 36 miospore genera are recorded. The two coal-bearing Lower Gordwana slices, referred to as Rongtong or Lower unit and Tindharia or upper unit in this paper, differ both in qualitative and quantitative distribution of miospore genera and miospore groups. It is also possible to divide each unit into zones on the basis of frequency distribution of some miospore genera and this zonation may prove helpful in the correlation of the coal seams of the area. Miospore assemblage of the coal is comparable with those from the Lower Gondwana of Peninsular India and suggests that Rongtong unit is equivalent to the upper Barakar, and Pankhabari-Bagrakote unit to the Raniganj assemblages respectively of Peninsular Lower Gondwana.
Geology of the Palaeozoic Sequence of the Kashmir Tethys Himalayan Basin in the Udder Valley, Jammu and Kashmir
Authors: Srikantiai S. V. , Bhargava O. N. 
Published: November 2024

Abstract
The Lidder Valley in Kashmir displays an excellent section of the Palaeozoic sequence of the Tethys Himalayan basin. The sequence earlier classified by Middlemiss (1910), however offers scope for revision in respect of lithostratigraphy and nomenclature. A new classification, adopting several new names, has been presented. The sequence is divided into Hapatnar Group, Chorgali Group, Lidder Group, Panjal Volcanic Group, Zewan and the Sonamarg Group in the ascending order. The paper discusses the details of lithostratigraphy, the need for new nomenclature, and the sedimentation and structure of the Tethys sequence in the Lidder Valley.
Uranium Mineralizanon in Singhbhum Shear Zone, Bihar: I. Ore Mineralogy and Petrography
Authors: Krishna Rao N. , Rao G. V. U. 
Published: November 2024

Abstract
More than fifty ore minerals have been identified in the uranium and copper deposits of the zone. Uranium occurs in several forms-uraninite, sooty pitchblende, refractory uranium-bearing minerals like allanite, davidite. sphene, xenotime, etc., secondary uranium minerals and uraniferous iron oxides. Other ore minerals include sulphides of Cu, Ni, Mo and Fe, tellurides of Bi and Ni and native metals Bi, Au, Ag and Te.
The structure, texture and paragenetic association of uranium minerals in the different sectors of the shear zone differ considerably, indicating varying physicochemical conditions of their formation. The study also shows that more than one episode of mineralization has taken place.
Mineralogy of Chromiferous Quartzites from South India
Authors: Raase P. , Raith M. , Ackermand D. , Viswanatha M. N. , Lal R. K. 
Published: November 2024

Abstract
The mineralogy of chromiferous quartzites from Archaean greenstone belts of southern Peninsular India has been studied. The majority of the quartzites are metamorphosed clastic sediments derived from a sialic source with enclaves of ultramafic chromite-bearing rocks. For the quartzites from the Ghatti Hosahalli belt, however, a volcanic-exhalative origin is most likely. The chromium in the sediments was fixed in the detrital chromite and/or the clay minerals.
The typical mineral assemblages developed in a wide range of metamorphic conditions from greenschist to amphibolite facies comprise fuchsite, quartz, kyanite and accessory rutile, tourmaline and Cr-spinel. Microprobe analyses show high chromium contents for fuchsite (2-4wt. % Cr2O3), kyanite (up to 6wt. % Cr2O3), rutile (1.0-2-6wt. % Cr2O3) and tourmaline (2.5-7.6 wt. % Cr2O3). Cr-spinels are essentially solid solutions between hercynite and chromite (Mg/(Mg+Fe2+)=0.060.15; Cr/(Cr+Al)=0.42-0.75). Comparison with igneous chromites indicates that compositional reequilibration during metamorphism was characterised by replacement of Mg by Fe2+ and, to a lesser extent, of Cr3+ by Al. The micas of chromiferous quartzites from the Chitradurga area have high Cr and Ba contents (1.4-3.9wt. % Cr2O3; 0.5-8.5 wt. % BaO) and represent solid solutions extending from muscovite to Cr-oellacherite, A baryte-bearing quartzite from the Ghatti Hosahalli belt contains the rare assemblage quartz, baryte, celsian (Cs85Or11Ab4), fuchsite (15 wt. % Cr2O3; 8.5 wt. % BaO), uvarovite (Uv71Gro28) and tremolite.
The regular distribution of chromium between mica and associated Cr-spinel, rutile and tourmaline indicates equilibration during metamorphism.
Structural History as an Aid in Precambrian Stratigraphic Correlation: An Example from the Gangpur Group in Eastern India
Authors: Chaudhuri A. K. , Pal A. B. 
Published: November 2024

Abstract
Gangpur Group, an important Precambrian metasedimentary sequence near Rourkela in eastern India shows an easterly antiformal closure, but the northerly younging towards the core shown by cross beds in the southern limb proves large scale inversion. Three generations of folds F1, F2 and F3 are proved on mesoscopic and macroscopic scales by structural analysis. The limbs and axial planes of low easterly plunging isoclinal reclined folds (F1) along with schistosity developed parallel to these axial planes are coaxially folded by upright F2 folds; N-S trending upright F3 folds cause culminations and depressions in axes of F1 and F2 folds. The stratigraphy of the complexly folded Precambrian Group is worked out on the basis of the structural model. One important marker horizon of carbonaceous quartz phyllite and banded quartzite recurs four times because of large scale axial plane folding.
Uranium Mineralization in Singhbhum Shear Zone, Bihar: III. Nature of Occurrence of Uranium in Apatite-Magnetite Rocks
Authors: Krishna Rao N. , Rao G. V. U. 
Published: November 2024

Abstract
Uraniferous apatite-magnetite veins occur in several parts of the Singhbhum Shear Zone, Bihar. Besides these veins, apatite and magnetite are ubiquitous minerals in the uranium ore deposits of the zone, with which too uranium values are associated.
Both primary and secondary uranium occur in the apatite-magnetite veins, though the latter is more abundant. Diadochic uranium in apatite lattice, inclusions of uraninite in apatite and uranium-bearing accessory minerals such as allanite, sphene, xenotime and rare monazite are the source of primary uramium. Secondary uranium is in the form of minerals like autunite, potassium autunite, uranophane and torbernite, uraniferous iron oxides and rare interstitial uraninite/pitchblende.
The relationship between uranium-bearing minerals and magnetite indicates that magnetite has played a role in the precipitation of uranium, not only in the apatite-magnetite veins, but also in the mineralised schists of the shear zone. Oxidation of Fe2+ to Fe3+ with the concomitant reduction and precipitation of uranium is the probable mechanism. This can take place both at elevated temperatures leading to coprecipitation of uraninite and hematite, and supergene and low temperature conditions which favour the formation of uraniferous iron oxides and fine-grained pitchblende.
Barr Conglomerate: Its Recognition and Significance in the Stratigraphy of the Delhi Supergroup in Central Rajasthan
Authors: Gangopadhyay P. K. , Lahiri Amitava 
Published: November 2024

Abstract
The lithostratigraphic units of the Delhi Supergroup are well exposed around Barr (26° 05': 74° 06'). Field, petrographic and geochemical observations from these units suggest that the lithofacies changes from lower arenaceous Alwar Group with basal polymictic conglomerate to the upper impure calcareous-cum-argillaceous Ajabgarh Group. The Barr conglomerate is truly a genuine sedimentary rock with assortment of pebbles and cobbles of quartzite, granite-gneiss, chert and mica schist. However, the conglomerate has been deformed along with other lithostratigraphic units of the Delhi Supergroup. Tectonically formed boudins can be distinguished from clastic pebbles and cobbles. The recognition of the sedimentary origin of the Barr conglomerate is useful in discussing the nature of Delhi-PreDelhi contact on the western flank of the 'Delhi synclinorium'.
On the Reaction-Rim Texture Tetrahedrite + Galena = Bournonite + Chalcopyrite
Authors: Mookherjee Asoke , Mishra Biswajit 
Published: November 2024

Abstract
Reaction rims of myrmekitically-intergrown bournonite and chalcopyrite occur selectively along the contact of galena and ferriferous antimonian fahlore grains but are absent along galena and arsenian fahlore grain contacts-sometimes even in the same specimen-from Rajpura-Dariba deposit. For amenability to thermodynamic treatment ferriferous tetrahedrite (for which no thermodynamic data exist) is treated as equivalent to pure tetrahedrite plus pyrrhotite and assuming the reaction tetrahedrite + pyrrhotite +galena + bournonite + chalcopyrite (with increasing aS2) ' the univariant line is calculated from published data. The particular sulfidation curve, set against the stability fields of associated minerals in the log aS2 - T space, suggests that the texture is due to low temperature reaction between pre-existing ferriferous tetrahedrite and galena crystallized from a late stage pulsation of ore fluid. The finding is consistent with the known, biphase mode of origin of the ore body.
Uranium Mineralization in Singhbhum Shear Zone, Bihar: IV Origin and Geological Time Frame
Authors: Krishna Rao N. , Rao G. V. U. 
Published: November 2024

Abstract
On the basis of an analysis of the various characteristics of the uranium deposits of the Singhbhum Shear Zone, a new sequence of events has been postulated to explain the origin of mineralization. The main events are:
(i) The Singhbhum Granite is the geochemical source of uranium, (ii) The metavolcanic rocks closely associated with the Chaibasa Formation rocks along the shear zone are the geochemical source of base metals, (iii) Uranium was first syngenetically deposited in the sediments of the Chaibasa Formation, (iv) This uranium was mobilized during metamorphic-metasomatic process, accompanied by shearing, leading to syntectonic granitization and extensive feldspathization. During this episode a part of the geochemical stock of uranium was incorporated in the metasomatic refractory uranium minerals, and the rest in (a) deuteric uraninite, (b) tiny crystals of uraninite included in metasomatic minerals and (c) molecular and ionic desserninations occluded in crystals and inter-granular fluids in the metasomatised rocks, (v) uranium was remobilized again by tectonically heated waters during further extensive shearing and redeposited as uraninite in suitable structural traps, (vi) emplacement of basic sills at Jaduguda aided this remobilization and exerted a geochemical control in precipitating uranium along with other metals such as Cu and Ni, (vii) in some parts of western sector (eg. Narwapahar) exogenic remobilization also played a part, (viii) the sooty pitchblende, secondary uranium minerals and supergene uraniferous iron oxides are due to subsequent local remobilization and deposition.
Thus, uranium mineralization in the Singhbhum Shear Zone is the result of a series of overalapping geological processes.
Ichnogenus Skolithos in the Tal Formation of Mussoorie Area
Authors: Singh Indra Bir , Shukla Vinal , Raj Vibhuti , Kapoor Pushkar Nath 
Published: November 2024

Abstract
Skolithos, comprising of thin, simple, unbranched vertical burrows are sometimes quite abundant in the siltstone of Arenaceous Member (tidal flat deposits) of Lower Tal Formation. They occur together in dense population resembling 'pipe rock'. The Skolithos burrows are 3-5 cm in length, and 2-5 mm in diameter showing a distinct wall; rarely showing narrow funnel-like widening at the mouth. In some cases the Skolithos burrows are paired, separated by a thin wall; but do not join together.
Clay Mineral Studies of Barail and Tipam Reservoir Sands in Assam, India
Authors: Bhattacharya N. 
Published: November 2024

Abstract
Studies by X-ray diffraction and scanning electron microscopy of the matrix material from these sands indicated that both allogenic and authigenic clays are present in the reservoir. Matrix of Barail sands are characterized by illite, chlorite and kaolinite which have undergone pronounced diagenetic changes. Montmorillonite and expandable mixed-layers are important clay minerals associated with reservoir sands belonging to the Tipam series. Grains, pores and channels are all heavily coated with expandable clays in Tipam sands; the grains, pores and pore throats are partially coated with matrix clays in Barail sands with rare development of bridges in permeability channels.
Barail sands were deposited in a transitional environment (deltaic/estuarine) while the environment of deposition was fluviatile for the Tipams. Clay minerals in the Tipam sands are very sensitive to formation damage while those in the Barails could result in permeability barriers if the particles are dislodged in the sands. Accordingly, precise control of salinity of formation water in steps during production and development is suggested.