bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineralogical and Geochemical Characteristics of the Basal Quartz - Pebble Conglomerate of Dhanjori Group, Singhbhum Craton, India and their Significance
Authors: Sunil Kumar T. S. , Krishna Rao N. , Palrecha M. M. , Parthasarathy R. , Shah V. L. , Sinha K. K. 
Published: November 2024

Abstract
he basal quartz-pebble conglomerate of Dhanjori Group of Singhbhum-Orissa craton is characterised by a distinct heavy mineral assemblage of pink zircon, chromite, pyrite, monazite and rutile-silicate intergrowth. Statistical analysis of morphometric features of zircons shows that they are significantly different from those found in Older Metamorphic Group and Older Metamorphic Tonalite Gneiss, but they have resemblance to those found in Singhbhum Granite. The trace and REE characteristics of the conglomerates, and the morphology and chemistry of zircon, identify the Singhbhum Granite Complex as the predominant source rock. At the same time, abundant detrital chromite, the positive trend of Cr-Ni and Cr-Co plots, and high Cr/Th ratios of the QPCs suggest a mixed provenance with an ultramafic component ofkomatiitic affinity (older greenstones) in the granite complex. The relative proportion of older greenstones was higher towards western and southern margins of the Dhanjori basin.
Taxonomy and Paleolatitudinal Significance of Rotorboides granulosum - A Less-Known Recent Foraminifera of Tropical Region
Authors: Kathal P. K. , Bhalla S. N. 
Published: November 2024

Abstract
The paper presenst taxonomic observations on the Rotorboides granulosum (Heron-Allen and Earland), a less known foraminiferid collected during the course of investigation of Recent littoral sediments along Palk Strait (9° N to 10° N) and Kakinada Bay, east coast of India. Systematics and the microstructure of this rotaliid, found in the shallow and protected tropical waters of the world since Middle Pliocene has been discussed vis-a-vis its origin and significance in the paleoenvironmental and paleolatitudinal reconstruction of the Tetiary strata, elsewhere.
Late Quaternary Oceanographic Changes in the Eastern Arabian Sea: Evidence from Planktic Foraminifera and Pteropods
Authors: Singh A. D. 
Published: November 2024

Abstract
Planktic foraminifera and pteropods were analysed qualitatively and quantitatively from two gravity cores recovered from the shelf off northern Kerala representing the past - 23 Ka record. Based on the temporal variation in the composition of faunal assemblages, oceanographic and climatic changes during late Quaternary are interpreted. A time-series of the monsoonal-upwelling indices suggests that between - 23 to 18 Ka BP minimum upwelling and weaker monsoon occurred. This period was followed by a gradual increase in the intensity of upwelling and monsoonal strength during - 18 to 15 Ka BP. After a breif interval of weak monsoon, it intensified again from -12 to 10 Ka BP. The southwest monsoon was weaker from - 5 Ka BP with minor fluctuations in its strength. The study also reveals that pteropod shells made up of aragonite (highly solution susceptible) are found in different states of preservation in response to oceanographic changes during the Quaternary. Three kinds of shells subjected to different modes of preservation occur in the cores: (i) transparent shells (excellent preservation), (ii) opaque-white shells and (iii) molds with original shells (corrosion and dissolution). The preservation of aragonite shells was excellent between - 23 to 18 Ka BP. Aragonite dissolution is recorded with its maximum from - 17 to 15 Ka BP. The pteropod shells are well preserved during Holocene.
Concentration of Gold in Natural Waters from Lateritic Terrain, Wynad-Nilambur Gold Field, Kerala, India and its Possible Role in Exploration
Authors: Narayanaswamy  , Balaram V. , Ramkumar N. , Anjaiah K. V. 
Published: November 2024

Abstract
Water samples from wells adjoining abandoned mines in the Wynad-Nilambur Gold Field were analysed by ICP-MS for gold and values ranging from 0.05 ppb to 0.22 ppb obtained. Though gold in the water samples is in very low concentration, the study suggests that it is possible to use water samples in hydrogeochemical prospecting for gold by adopting ICP-MS instrumental technique after preconcentration of gold by activated charcoal. The procedure is very sensitive with detection limit approaching 0.1 parts per trillion.
Analysis of Pumping Test Data from Abstraction Well
Authors: Singh V. S. , Thangarajan M. 
Published: November 2024

Abstract
In many situations pumping tests are carried out without observation well and drawdown/recovery, data recorded in the pumped well itself. Although, the time drawdown/recovery data are, being precisely recorded in the pumping well, the interpretation of such data often gives ambiguous results due to non-accountabiiity of well loss and well storage in many situations. This is particularly true in the case of low permeable aquifer. In order to overcome such difficulties, finite difference, method is used to estimate aquifer parameters. Field examples are presented to illustrate the above method.
Discovery of Lower Cambrian Small Shelly Fossils and Brachiopods from the Lower Vindhyan of Son Valley, Central India
Authors: Azmi R. J. 
Published: November 2024

Abstract
R. J. Azmi of the Wadia Institute of Himalayan Geology here reports the discovery of small shelly fossils and brachiopods of lower Cambrian affinity from the topmost Rohtasgarh Limestone at Maihar and Rohtas in the Son Valley. This discovery is of importance as it necessitates a revision in the age of the Vindhyan succession. We welcome a discussion on this subject - Ed.
Petrology, Geochemistry and Stable Isotope Studies of Carbonate-Rich Dyke-Like Bodies, Chhaktalao Area, Madhya Pradesh
Authors: Hari K. R. , Satish Kumar M. , Santosh M. , Rai Suneet Kumar 
Published: November 2024

Abstract
Carbonate-rich rocks occur as E-W trending dyke-like bodies in the Deccan 'basalts at Chhaktalao area in the lower Narmada valley and show a structurally controlled mode of emplacement. Modal composition shows calcite as the dominent mineral (~90%). Ankerite, apatite, altered olivine, augite and opaques account for the remaining percentage. Geochemically, these rocks show high CaO (&gt;50%) with low SiO2, TiO2, FeO* and K2O. Trace element concentrations are low compared to average carbonatites. Stable isotope studies show that d13C(-1.74‰ to -2.8‰) and d18O(+12.75‰ to +13.35‰) values do not compare with those of "primary igneous carbonatites" eventhough they fall within the wide range of "igneous carbonatites". These rocks can be considered only as carbonate-rich rocks and not as true carbonatites.
Geology, Petrology and Geochemistry of Narayanpet Kimberlites in Andhra Pradesh and Karnataka
Authors: Rao K. R. P. , Reddy T. A. K. , Rao K. V. S. , Rao K. S. B. , Rao N. V. 
Published: November 2024

Abstract
Apart from the well known occurrence of kimberlites in south India at Wajrakarur in Anantapur district, kimberlites were located by Geological Survey of India (GSI), during 1984-85 around Maddur and Narayanpet areas in Mahabubnagar district of Andhra Pradesh. Landsat imagery and photo-interpretation studies followed by intense geological traverses including stream sediment surveys, launched during 1994-96, led to the discovery of 20 additional kimberlites in the western part of Mahabubnagar district, Andhra Pradesh and in the adjoining Gulbarga district, Karnataka, thus reporting kimberlite for the first time from the state of Karnataka. A total of 30 kimberlites have been reported in this field named as "Narayan pet Kimberlite Field" (NKF).
The kimberlites are emplaced along E-W and NW-SE trending major faults and associated NE-SW tear faults in the Peninsular Gneissic Complex carrying enclaves of Dharwar greenstones of Gadwal schist belt. These kimberiites occur both as small bodies of a few metres across and also as dykes with a strike length of about 2 km. The characteristic mineral assemblages and textures indicate that these bodies correspond to hypabyssal facies or root zone kimberlites. The indicator mineral suite present in these rocks are olivine, chrome diopside, magnesian ilmenite, chrome spinel, ai1d rare pyrope garnet Mantle xenoliths are rare, nevertheless spinel Iherzolite; abundantly found in two kimberlites.
All the kimberlites of NKF are depleted in SiO2 (~ 35%), potassic (K2O &gt;Na2O) and magnesium rich (MgO &gt;20%). The REE abundance of these kimherlites is consistent with their derivation by partial melting of mantle and subsequent fractional crystallisation of the melt. The similarity of petrological and geochemical characters of these kimberlites indicate that all the kimberlites of NKF are derived from similar source in the upper mantle.
Preliminary processing and testing of some of the kimberlite bodies have not yielded any diamonds so far. However, the reported stray diamond finds in the Krishna and Bhima River gravels indicate the presence of diamondiferous kimberlites further south and southwest of the area.
Miocene Radiolaria from Nicholson and John Lawrence Islands, Andaman Sea
Authors: Sharma V. , Daneshian J. 
Published: November 2024

Abstract
One hundred and thirty three radiolarian taxa from two sections, one each at Nicholson Island and John Lawrence Island, Andaman Sea are reported. The assemblage is referable to upper Calocycletta costata Zone to lower Dorcadospyris alata Zone (late Early Miocene to early Middle Miocene, about 16.9 Ma to 15.9 Ma). Stratigraphic ranges of some selected species are compared with those in the deep sea drilling sites in the tropical Indian Ocean.
Principles of Mise-a-la-Masse Method and its Application to Polymetallic Sulphide Deposits of Rajasthan
Authors: Gupta Dinesh , Shyam Radhe , Agarwal A. K. , Bhattacharya B. B , Banerjee B. 
Published: November 2024

Abstract
In surface geophysical surveys, resistivity contrast between the ore and host rock plays a vital role in the success ratio of the surveys. To overcome the problem of insufficient resistivity contrast, a modified method, Mise-a-la-masse, as tried and found to be very effective in tracing the extensions of polymetallic sulphides intersected in a borehole. The method was applied to Pb-Zn and sulphide hosted gold prospects in Rajasthan and the results obtained indicate that Mise-a-la-masse method can be successfully employed for delineating subsurface extension of polymetallic sulphide deposits.
Long-Period Fluctuations in Monsoon Floods in the Deccan Peninsula, India
Authors: Kale Vishwas S. 
Published: November 2024

Abstract
In the present study, the temporal patterns of monsoon floods on five large rivers of the Deccan Peninsula have been investigated. Analyses of the long-term annual maximum discharge/stage data, available for the last 100 years or so, show non-random behaviour in terms of distinct periods of high and low floods. The normalized accumulated departure from mean (NADM) plotting method has been used to identify great periods of below-average (low) and above-average (high) floods. Examination of the data reveals lower frequency and magnitude of large floods during the late-1800 and early-1900 period, and a period of increased frequency of large floods between 1940s and 1960s. The results of the investigation also indicate that the high (low) flood response is consistent with increased (decreased) precipitation in the basins. There is a clear evidence of an enhancement in the magnitude and frequency of large floods in the post-1940 period.
Mid-Proterozoic Intraplate Alkaline Magmatism in the Eastern Dharwar Craton of India: The Cuddapab Province
Authors: Madhavan V. , Mallikharjuna Rao J , Srinivas M. 
Published: November 2024

Abstract
In the Dharwar craton, the recently recognized Cuddapah intrusive province hosts an array of mid-Proterozoic alkaline and non-alkaline intrusives; the latter are represented by two manifestly voluminous magma types: gabbro and granitoid, which are marked by a bimodal association. Here we present the tectono-magmatic framework of the Cuddapah intrusive province and in the light of it, the petrology, geochemistry and genesis of alkaline rocks are discussed to highlight the mid-Proterozoic intraplate alkaline magmatism in the eastern Dharwar craton.
Exhumation History of Eclogites from the Tso-Morari Crystalline Complex in Eastern Ladakh: Mineralogical and Fluid Inclusion Constraints
Authors: Sachan K. H. , Bodnar R. J. , Islam R. , Szabo Cs. , Lawi R. D. 
Published: November 2024

Abstract
Eclogites from the Tso-Morari Crystalline Complex in Ladakh, India, preserve evidence for high P, low T metamorphism of subducted Indian continental crust in the presence of a moderate salinity aqueous fluid phase. The phengite barometry estimates a pressure range of 11-14 kbar for eclogitization whereas garnet-omphacite geothermometry reveals a temperature range of 530°-580°C. Following eclogitization at 530°-580°C at a minimum pressure of 14 kbar, the eclogites were tectonically exhumed along a nearly isothermal P-T path that brought them to within 10-30 kilometers of the surface. Final transport to the surface followed a more normal continental geotherm.
Geothermometry of the Granitoids of Eastern Higher Kumaun Himalaya, India
Authors: Kaur Manudip , Chamyal L. S. , Sharma N. , Jowhar T. N. 
Published: November 2024

Abstract
The granitoids of eastern Higher Kumaun Himalaya show a metamorphic history extending from the Precambrian to Tertiary. The granitisation and formation of the granitoids within the Higher Himalaya were related to an early metamorphism (M1) that took place during Precambrian. Temperatures of the granitoids of eastern Higher Kumaun Himalaya are estimated based on co-existing feldspar pairs, alkali feldspar-muscovite geothermometer and Ti content in micas and are found to be in conformity with temperatures prevailing in the upper amphibolite facies.
Facies Pattern and Depositional Motif in an Immature Trench-Slope Basin, Eocene Mithakhari Group, Middle Andaman, India
Authors: Chakraborty Partha Pratim , Pal Tapan , Gupta Tanay Dutta , Gupta Kalyan Surya 
Published: November 2024

Abstract
Detailed facies analysis in Eocene Mithakhari Group reveals eight different lithofacies of wide ranging paleogeographic significance. These facies are i) disorganised matrix-supported conglomerate, ii) graded matrix-supported conglomerate, iii) graded pebbly sandstone, iv) massive and thick-bedded sandstone, v) plane laminated and cross-stratified sandstone, vi) interbedded sandstone and mudstone, vii) massive to faintly laminated shale and viii) interbedded shale and coal; which are grouped into-five different facies associations (FA). viz. Subaerial alluvial plain (FAl), Shallow water, wave dominated shelf (FA2), Delta slope (FA3), Prodelta slope (FA4) and Submarine fan (FA5).
Lying unconformably on oceanic basement (ophiolite slices?) these sediments constitute short truncated successions. Litholog measurement in three isolated sections viz. Kaushalyanagar. Sagwannala and Rangat-Nimbutala reveal widely varying facies succession pattern. Frequent facies change, predominance of massflow deposits, signatures of synsedimentary basinal disturbance and wide paleogeographic variation indicate sedimentation in small isolated basins in an immature trench-slope setting. Profusion of progradational depositional cycles and evidences of emergence in the studied sections provide indication of frontal accretion and tectonic shoaling in the filling history of these basins.
Origin of the Sung Valley Carbonatite Complex, Meghalaya, India: Major Element Geochemistry Constraints
Authors: Sen Amit Kumar 
Published: November 2024

Abstract
The Sung Valley carbonatite complex is situated in the Shillong Plateau, Meghalaya and includes an array of silicate rocks along with sovitic carbonatite. The silicate rocks are represented by serpentinized peridotite, pyroxenite, melilitolite, ijolite and nepheline syenite and occupy more than 99% of the total outcrop. Variation in major element composition divides the silicate rocks into two distinct groups: i) alumina-alkali-poor, represented by peridotite, pyroxenite and melilitolite and ii) alumina-alkali-rich consisting of ijolite and nepheline syenite. Perceptible variation in chemical composition can also be noted among the individual group members. The carbonatite is dominantly CaCO3-rich and poor in alkalies. Present study suggests that the parent magma in the Sung Valley complex was of melilitic composition. In the initial stages this magma produced peridotite and pyroxenite by fractional crystallization. With progressive crystallization the parent magma gradually became enriched in Ca and generated carbonatitic melt by liquid immiscibility. The residual silicate melt, after separation of immiscible carbonate melt, produced ijolite and nepheline syenite by fractional crystallization.
Late Proterozoic Bimodal Volcanic Assemblage of Siwana Subsidence Structure, Western Rajasthan, India
Authors: Bhushan S. K. , Chittora V. K. 
Published: November 2024

Abstract
Neoproterozoic Malani bimodal volcanism occurs in a cauldron subsidence structure of a shield volcano at Siwana. This collapse caldera has exposed 45 volcanic flows comprising six of basalt, 20 of rhyolite, alkali rhyolite and rhyodacite, 15 of trachyte, one of dacite and three of trachyandesite, composition. Major and trace element geochemistry of lavas shows a bimodal character in the mafic and felsic components. The lower felsic flows are alkaline and highly enriched in HFS elements while the upper flows are peraluminous in composition. Alkalinity has been reintroduced in the uppermost flows. Wide variation in incompatible trace element ratios indicates a nonfractional crystallization relationship between the mafic and felsic magma. Malani volcanism was triggered in an extensional tectonic setting where geotherm was raised by the repeated influx of basaltic magma. Crustal extension inhibited the bouyant rise of silicic magma.
Characterization of Groundwater in the Unconfined Aquifers of Chennai City, India, Part 2 - Factor Analysis
Authors: Ballukraya P. N. , Ravi R. 
Published: November 2024

Abstract
Hydrogeological studies of the groundwater in Chennai area have shown that the alluvial aquifers have several geochemical facies with distinct characteristics. Factor analysis of the data has been helpful in characterising these facies, since it is noticed that the factor 1 measures salinity, hardness and alkalinity, while factor 2 measures pollution. It is observed that lithology, land use and hydraulic characteristics exercise significant control on the geochemistry of groundwater. The behaviour of groundwater quality in coastal areas, river banks and surface reservoirs is also well explained by factor scores and many of these form distinct hydrogeochemical facies. The study further shows that the geochemistry of the groundwater in these categories gets much more distinct in the pre-recharge periods indicating the effectiveness of the rock-water interaction in the aquifers.
Sheath Fold in Charnockite Around Nekkanamalai, Vellore District, Tamil Nadu
Authors: Ganesan T. M. , Gopalakrishnan K. , Renganathan R. , Sivasankaran S. S. 
Published: November 2024

Abstract
A sheath fold with inverted hinge is recorded within the charnockite exposed around Nekkanamalai in the Southern Granulite Terrain. The area lies within the NNE-trending Gudiyatham-Bhavani Straight Belt (GBSB) bounded on either side by two distinctly different tectono-stratigraphic terranes brought into juxtaposition along major tectonic contacts. Such folds are known in regions of re-folding, with later folding events of high intensity at high angles to the earlier folds, as well as in shear zones, where the direction of shear is subparallel to the sheath axes. The sheath fold in the area is interpreted to be due to superposed folding resulting from the complicated pattern of deformation produced during the welding of different terranes along the GBSB, which had brought about not only plunge reversals but also plunge inversion of the earlier folds.
Mineralogy of Gold and Associated Alloys in Sulfides of Bhukia Gold Prospect in Southeastern Rajasthan, Western India
Authors: Golani P. R. , Rajawat R. S. , Pant N. C. , Rao M. S. 
Published: November 2024

Abstract
Primary gold occurs with sulfides in Paleoproterozoic Aravalli rocks in the Bhukia area of Banswara District, Rajasthan. It occurs as microscopic grains of various shapes, mainly in arsenopyrite and lollingite. With a combined approach of ore petrologic and EPMA studies, we report high purity gold, native bismuth and alloys of gold-bismuth and bismuth-tellurium which best approximate to the rare minerals maldonite and wehrlite respectivety. The fineness of gold ranges between 934 and 995. Preliminary estimates on temperature using arsenopyrite composition coupled with rare presence of spherulitic graphite indicate the temperature of equilibration of around 550°C for the coexisting mineral phases of pyrrhotite, arsenopyrite and lollingite.
Velocity-Depth Relationship in Selected Parts of Indian Crust
Authors: Kumar Prakash , Tewari H. C. , Sain K. 
Published: November 2024

Abstract
Deep Seismic Sounding (DSS) studies were started in India in 1972, but till date no attempt has been made to synthesize the data to provide a bird's eye view of the variation in crustal model. Present synthesis of seismic data provides a glimpse of change in the regional velocity scenario as well as basement and Moho depth configurations in selected parts of the Indian crust. In the sedimentary basins of east-coast, Bengal and Cambay, the basement depth varies between 2 and 10 km, and the Proterozoic Vindhyan and Cuddapah basins show maximum depths of 5 and 10 km respectively. The maximum Moho depth is indicated as 42-44 km in the central Indian region.
A Fluid-Rock Interaction Model for Carbon and Oxygen Isotopic Variations in Altered Carbonatites
Authors: Ray Jyotiranjan S. , Ramesh R. 
Published: November 2024

Abstract
A fluid-rock interaction model for treating the stable carbon and oxygen isotopic variations in altered carbonatites is presented and illustrated with an example using data from the ferrocarbonatites of Amba Dongar, Gujarat. The Amba Dongar ferrocarbonatites appear to have been altered by a fluid of magmatic origin at 100 to 200°C contrary to an earlier suggestion of meteoric groundwater alteration at ~50°C.
A Note on Inch Scale Layering in a Dolerite Dyke of the Deccan Trap of Saurashtra, India
Authors: Sethna S. F. , Kothare Prajakta , Javeri Priya 
Published: November 2024

Abstract
Distinct vertical rhythmic layering is seen in one of the dykes 68 km southeast of Rajkot. The dyke extends for almost 50 km in length but has a limited width of 10 to 15 metres. The vertical layering is due to alternating layers rich in plagioclase and pyroxene, which is encountered mainly in the central part of the dyke. The layering is formed due to molecuIar diffusion at the front of cooling and crystallization with the temperature gradient catching up gradually to form the next layer. Alternatively it may be possible that layering is due to multiple injections of melt into the fracture that was responsible for disturbing the equilibrium from time to time.