bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Observations on the Geochemistry of Ramannapeta-Ustapalle Lamproitic Body, Krishna District, Andhra Pradesh
Authors: Chalapati Rao N. V. , Madhavan V. 
Published: November 2024

Abstract
Detailed petological and geochemical studies pertaining to the lamproitic body recorded by the Geological Survey of India at Ramannapeta-Ustapalle, Krishna district, Andhra Pradesh, are presented. Unmistakable lamproite signatures like the presence of Ti-rich potassic richterite, abundance of Ti-rich, Al-poor phlogopite and Ca-rich, Al-poor clinopyroxene, absence of primary calcite, paucity of typical kimberlite indicator minerals and the ultra potassic nature are recognised. Major oxide as well as the trace elemental abundances of the body are observed to be similar to those of the Chelima lamproites occurring within the intra-cratonic Cuddapah basin. The available radiometric ages of all the known Indian lamproites and kimberlites are taken into consideration and a mid-Proterozoic lamproite event in the Indian sub-continent is postulated.
Sediments of the Bharathapuzha, Kerala: Implications of Downstream Trends of Texture and Grain Shape
Authors: Anirudhan S. , Thrivikramaji K. P. 
Published: November 2024

Abstract
The results of analysis of textural parameters of channel sediment samples of the Bharathapuzha system using the scheme of McLaren and Bowles (1985) reveal the existence of Case B trend in the direction of transport for mainstream (Bharathapuzha) and two high gradient tributaries viz., Gayathcipuzha and Thuthapuzha. Further, Fourier amplitude spectra estimated from digitized data of grain boundaries of the sand grade sediment from selected samples and the Waddell's sphericity and roundness indices demonstrate that influx of sediment from tributaries does not alter the size or shape distribution trends of the mainstream sands to any extent.
Structural Geometry of the Rocks of the Southern Part of the Nallamalai Fold Belt, Cuddapah Basin, Andhra Pradesh
Authors: Matin Abdul , Guha Jaydip 
Published: November 2024

Abstract
A sequence of quartzite, banded phyllite and slate in the southern part of the Nallamalai fold belt shows a series of macroscopic gently plunging folds (DI) with NW-SE striking axial plane and a pervasively developed axial planar slaty cleavage. A weak later deformation has produced sporadic gentle folds (D2) with axial planes at high angle to the D1 fold axial planes.
The rocks along the eastern contact of the belt are mylonitized and the intensity of deformation gradually dies away towards west. A zone of tectonic dislocation is envisaged between the basement granite gneiss towards the east and the supracrustal Nallamalai rocks.
Ostracode Fauna of the Niniyur Formation (Palaeocene), Cauvery Basin, Tamil Nadu, Southern India
Authors: Mallikarjuna U. B. 
Published: November 2024

Abstract
A rich and interesting ostracode assemblage comprising 29 taxa, are recorded from the Niniyur Formation of the Cauvery Basin, Tamilnadu, Southern India. Of these, 6 species are new, 19 species are already reported and 4 species are left under open nomenclature. The new species are Hemicyprideis oertlii, Cyamocytheridea? niniyurensis, Costa niniyurensis, Stigmatocythere gowdai, Protobuntonia Jaini and Ponlocyprella niniyurensis. The present paper gives distribution, age and affinity of the fauna with systematic descriptions of six new species and four indeterminate species. The assemblage shows affinity to Palaeocene and Eocene forms of Western Europe, Saudi Arabia, Pakistan and other areas in India. The overall palaeontological evidences suggest a Palaeocene age for the Niniyur Formation.
Sr, Pb and Nd Isotope Studies and their Bearing on the Petrogenesis of the Jalor and Siwana Complexes, Rajasthan, India
Authors: Dhar Sunil , Frei Robert , Kramers Jan D. , Nagler Thomas F. , Kochhar Naresh 
Published: November 2024

Abstract
The Jalor and Siwana complexes belong to the Malani igneous suite, Rajasthan, India and are characterised by within - plate, A - type granites associated with coeval felsic and mafic volcanism. Sr, Pb and Nd isotopic compostions of the two complexes have been determined. Sr isotopic studies reveal an isochron age of 725±7 Ma for the felsic rocks of the Jalor Complex, with an initial 87Sr/86Sr ratio of 0.7062±0.0020. Three highly differentiated granites from Siwana plot on the same near-isochron, indicating that the complexes are coeval. The Pb and Nd isotopic ratios range between (206Pb/204Pb = 18.52-21.28, 207Pb208Pb = 15.58-15.98, 204Pb/204Pb/206Pb = 38.53-40.8) and (143Nd/144Nd = 0.5122-0.5127, 147Sm/144Nd = 1.1260-0.157) respectively. Pb and Nd isotopic compositions of the Siwana samples show that the magma is mantle derived; for the Jalor complex the combined Sr, Nd and Ph data indicate primary mantle derivation with a variable degree of crustal contamination. with the assimilated crust being most likely of Archaean age.The petrogenesis of the two complexes is interpreted as an effect of fractionation of a primary mantle derived magma, simultaneous with assimilation of rocks from the lower crust. The data further document the presence of Archaean crust in the area.
Distribution of Organic Matter, Iron and Manganese in the Estuarine Clay of Mangrove Sediments, Tellicherry, Kerala
Authors: Thamban M. , Reghunadh K. , Sajan K. 
Published: November 2024

Abstract
The surficial mangrove sediments in the estuarine course of Eranholi river were sampled at 21 locations and analysed for the determination of organic matter, iron and manganese in 2 mm size fraction of the sediments. The study indicated that the these constituents are apparently controlled by the spatial variation of the physico - chemical factors of the estuary such as pH and Eh, base exchange and adsorption characteristics and the texture of the sediments, tidal influence and proximity to the mangrove vegetation in the prevailing estuarine environment.
Ostracodes from the Ariyalur Group (Late Cretaceous), Cauvery Basin, Southern India
Authors: Mallikarjuna U. B. , Nagaraja H. M. 
Published: November 2024

Abstract
Fifty-two ostracode taxa are recorded from the Ariyalur Group (Late Cretaceous), Cauvery Basin, Southern India. Of these, seven are new, thirty-nine already reported and six left under open nomenclature. The new species are Cytherelloidea jaini, Curfsina Sastryi, Limburgina gowdai, L. mannikerii, L. guhai, L. khoslai and Pontocyprella ariyalurensis. The paper gives systematic description of seven species and revised/synonymised list of ostracode species reported earlier.
Carbonatite Dykes from Kudangulam Area, Near Cape Comorin, Tamil Nadu
Authors: Ramasamy R. 
Published: November 2024

Abstract
Occurrence of dyke rocks of carbonatites in charnockites and granite gneisses near Kudangulam village situated 20 km NE of Cape Comorin, Tamil Nadu is reported. Petrography and Chemical composition of these rocks reveal that coarse grained curbonatites were formed under subvolcanic miarolitic crystallization from a degassed carbonatitic melt.
Colour-Coded Compositional Mapping of Reaction Textures in a Calc-Silicate-Charnockite Interface at Nuliyam, Kerala
Authors: Satish Kumar M. , Santosh M. , Yoshikura S. , Yoshida M. 
Published: November 2024

Abstract
Colour-coded compositional mapping under an electron microprobe provides useful information on chemical gradients within the domain of individual minerals. Here we apply this technique to granulite facies reaction textures from a calc-silicate-charnockite interface at Nuliyam, southern Kerala, to understand the element mobility patterns and mass balance related to fluid-induced metasomatism during deep crustal metamorphism. The contact zone assemblage at Nuliyam is characterized by plagioclase + quartz symplectites after K-feldspar. From element mapping of this reaction interface on micron - scale, and from quantitative analyses of the individal mineral phases under an electron microprobe, we trace the diffusion of K, and addition of Na and Ca, through an open system migration dUling the influx of externally-derived CO2-rich fluids. Our study provides the first direct evidence for microscale chemical diffusion associated with CO2-induced charnockite formation in southern Kerala, and illustrates the potential of colour-coded compositional mapping in tracing element mobility patterns.
Mundwara Alkali Igneous Complex, Rajasthan, India: Chronology and Sr Isotope Systematics
Authors: Rathore S. S. , Venkatesan T. R. , Srivastava R. K. 
Published: November 2024

Abstract
Six whole rock samples have been dated by 40Ar/39Ar method to ascertain the emplacement time of the Mundwara Alkali Igneous Complex, Rajasthan, India. The dated samples include four from the Musala hill and one each from Mer and Toa hills of the complex. Out of these, only two syenite samples. viz. MR 86/4 and MR 86/7 from the Musala and Mer hills, respectively, have given plateaus at 64 Ma, while the remaining samples have exhibited saddle shaped spectra owing to the presence of excess argon. However, similar isochron ages of about 70 Ma obtained from a basalt (Musala hill) and a gabbro (Toa hill) by linear regression of all the data points might suggest initiation of igneolls activity at Mundwara around 70 Ma ago.
87Sr/86Sr ratios of this suite range from 0.70385 to 0.70551 indicating its derivation from a mantle source.
Contrasting Precambrian Mafic Dykes of the Bastar Craton, Central India: Petrological and Geochemical Characteristics
Authors: Srivastava Rajesh K. , Hall R. P. , Verma R. , Singh R. K. 
Published: November 2024

Abstract
Numerous mafic dykes occur within the Archacan-granite-gneisses of the Bastar (Bhandara) craton of central India. Width of these dykes varies from about 20 to 200 metres and are 1 to 20 kilometers long. The dykes trend mainly NW-SE, following the foliation of the granite gneiss and major regional structural trend. They mainly comprise two different types, one, amphibolitic and the other doleritic. The amphibolite dykes have a granoblastic texture whereas the unaltered dolerite dykes are ophitic or sub-ophitic. All of the dykes are sub-alkaline Fe-rich tholeiites. However, variations in the incompatible elements such as Nb, P, Ti, Zr, Y and the light rare earth elements (LREE), suggest that the Bastar dykes infact comprise two different sets. The amphibolite dykes were derived from an earlier relatively high-Mg, low-Ti olivine tholeiite magma. These dykes have high field strength element (HFSE) values only around six times higher than those of primordial mantle. In contrast, the doleritic dykes have fractionated HFSE levels 10 to 30 times higher than primitive mantle values; they are also characterised by a marked negative Sr anomaly not present in the older dykes. One subset of amphibolitic dykes corresponds geochemically to the predominantly doleritic swarm. These latcr dykes are derived from a low-Mg, high-Ti quartz-tholeiitic magma. The two different Bastar dyke sets are recognized here as the older, BD1 amphibolitic dykes and younger, BD2 doleritic dykes. Age constraints for these dykes are set by the ages of the enveloping host gneisses and discordant granitoids and hence they are placed at or near the end-Archaean.
Structural Patterns in the Sausar Group Around Mansar, Nagpur District, Maharashtra
Authors: Mohanty A. K. , Mohanty S. 
Published: November 2024

Abstract
The Precambrian rocks of the Mansar area, Nagpur district, Maharashtra, belong to the Sausar Group and the Tirodi Gneiss. Both these lithological units show an unconformable relation in the area, marked by a conglomerate at the base of the Sausar Group. The metasediments of the Sausar Group bear imprints of polyphase deformation. The folds of the first generation (F1) are isoclinal with high amplitude to wavelength ratios and pervasive axial planar cleavage (S1). The structures of the second generation are represented by WNW-ESE trending upright isoclinal folds (F2) and axial planar crenulation cleavage (S2). Gentle upright folds with NE-SW striking axial planes represent structures of the third generation (F3) Superposition of F2 folds on F1 folds is marked by mushroom shaped interference pattern in small-scale. Because of upright isoclinal nature of F2 folds on WNW-ESE striking axial planes, the metasedimentary bands extend in E-W direction. Slight arcuate geometry of the metasedimentary bands is the result of superposition of F3 folds on F1/F2 folds.
Significance of Peat on the Western Continental Shelf of India
Authors: Mascarenhas Antonio 
Published: November 2024

Abstract
Peat layers 2 to 30 cm in thickness, 22 to 46 m below present sea level, are found along the inner shelf of India, up to 27 km from the coast. They are rich in plant debris, organic carbon and sulfur. These organic-rich layers are not sedimentary deposits. Lack of favourable substrates, absence of sheltered habitats, high energy physical environments, and a very rapid sea level rise during early Holocene indicate an unfavourable paleogeography and adverse oceanographic conditions for mangrove development and in situ peat formation. On the contrary, significant siliciclastic minerals, lithogenous elements and type III kerogen suggest a continental origin of peat. Restricted thickness, limited lateral distribution, absence of matted structures and laminated deposition imply transport of organics. Anomalous ages of wood with respect to present sea level are evidences of sediment reworking. Hence, peats on the continental shelf are not transgressive deposits.
Diversity of Planktonic Foraminiferal Assemblages From Quaternary Sequences at DSDP Sites 219, 220 and 241 in Northern Indian Ocean
Authors: Sarkar Ashish , Guha Asit K. 
Published: November 2024

Abstract
The Quaternary planktonic foraminiferal assemblages from DSDP Sites 219,220 and 241 in Northern Indian Ocean have been analysed in terms of diversity changes along the depth of each core. For an understanding of the population dynamics in the region and its relation to the paleoclimatic events (Ericson zones), relative abundance at family and species levels have been studied. Different indices of diversity viz., S, D, Hand E have been worked out and correlated with that of the oscillation in paleoclimatic record, which is based on the fluctuation in abundance of Globorotalia menardii along the depth of the core. It has been noted that during the Quaternary, relative abundance of different species and changes in diversity indices match well with that of the Ericson paleoclimatic zonation, enabling recognition of different stages of glacial and interglacial episodes in Northern Indian Ocean.
Clay Mineralogy of Argillites of the Precambrian Iron Ore Group, Noamundi Basin, Eastern India
Authors: Sambasiva Rao V. V. , Dasgupta H. C. 
Published: November 2024

Abstract
Clay mineralogy of the Precambrian argillaceous rocks of the Iron Ore Group from the Noamundi basin, is represented mainly by kaolinite and illite. In general. the kaolinite/illite ratio, the illite crystallinity and the (060) peak position and (002)/(001) peak height ratio of illite change systematically from the stratigraphically higher upper shales to lower shales and suggest diagenetic neoformation of illite in these rocks. Dominance of 2M1 polytype of illite in both the upper and lower shales, the range of illite crystallinity values and the absence of pyrophyllite in the assemblage indicate a maximum of epizone condition of metamorphism (-360°C/2kb) for these sediments. Growth of illite during diagenesis and paucity of chlorite indicate that the detrital sediments which accumulated in the basin were rich in kaolinite but poor in smectite group of minerals. The overwhelming dominance of kaolinite in the initial detrital physil input to the basin. its prolonged persistence and the non-opaque heavy mineral assemblage comprising mainly tourmaline, hornblende and zircon in the sand fraction suggest a granitic provenance and a non-marine condition of deposition for the sediments.
Ferromanganese Encrustation from Laksbadweep Area, Arabian Sea
Authors: Charlu T. K. , Kalluraya V. K. K. 
Published: November 2024

Abstract
Ferromanganese encrustation is reported from the central Lakshadweep area along the northern flank of Chetlat Island. It has comparatively high contents of Co, Ni, Ag and Pt and a MnlFe ratio of &lt;1. This hydrogenous encrustation is similar in composition to those from the equatorial Mid-Atlantic Ridge.
Carbon, Oxygen and Uranium Isotopic Study of Uraniferous Dolostone from Cuddapah Basin, Southern India : Implications to Depositonal Environment and Uranium Alteration
Authors: Bhattacharya S. K. , Sarin M. M. , Roy Minati , Dhana Raju R. 
Published: November 2024

Abstract
The dolostones show a narrOw range of d13C values but a large range of d13O values. The small spread of d13C from 0.1‰ to -0.9‰ is typical of marine carbonates, whereas the large range of d13O from -7‰ to -14‰ represents characteristic Proterozoic marine carbonates some of which were exposed to alteration by fresh continental waters. A diagenetic environment of mixed marine and fresh water for the dolostone alteration is also supported by earlier studies in sedimentary structures and petrography. The 234U/238U activity ratio of 0.7 in some of the mineralised samples shows the effect of ongoing chemical leaching of uranium from discrete uranium minerals like pitchblende and coffinite.
Fluid Inclusions in Migmatites from Hunsur, Karnataka
Authors: Srikantappa C. , Venugopal L. 
Published: November 2024

Abstract
Fluid inclusion studies in migmatites around Hunsur document the presence of a) CO2-CH4, CO2 and CO2-H2O inclusions in paleosome, b) predominantly CO2 inclusions in leucosome and c) CO2 and low salinity aqueous inclusions in late pink granite.
Chronological studies of CO2 inclusions in quartz grains from migmatites and their densities corresponding to Th maxima plus mineral P-T data for the regional metamorphism indicate that they are syn-migmatitic fluids. An internal origin of CO2 inclusions during the process of migmatization is envisaged.
Chemostratigraphy of Sedimentary Sequences: A Review of the State of the Art
Authors: Das Nachiketa 
Published: November 2024

Abstract
Chemostratigraphy of sedimentary sequences involves the application of major- and trace-element geochemistry for the characterisation and subdivision of sedimentary sequences into geochemically distinct units and correlation of strata in sedimentary basins. Chemostratigraphic correlation is particularly applicable to sequences that have very poor biostratigraphic control or to thick. rapidly deposited sequences that cannot be subdivided further by biostratigraphic data.
In order to maximise the number of geochemical characteristics of a given sediment, it is important to determine as many elements as possible. Such characterisation now routinely involves the analytical determination of concentrations of approximately 50 elements. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS) enable the rapid acquisition of major- and trace-element data for a large number of elements. Elements of simple mineralogical affinity, limited or no involvement in diagenetic activity and high concentration in refractory minerals are most suitable for chemostratigraphic correlation purposes.
Chemostratigraphic correlation is carried out on a reservoir scale as well as on a basin-wide basis for inter well correlation. The major- and trace-element data generated for chemostratigraphic correlation purposes could also be applied to studies of provenance and basin evaluation, diagenesis, reservoir characterisation and interpretation of wireline logs. In this review article, five case studies are also discussed in brief to demonstrate the applicability of chemostratigraphic correlation.
Diagenetic Effects on Sandstone Reservoirs of Nannilam Field, Cauvery Basin
Authors: Lahiri G. , Hardas M. G. 
Published: November 2024

Abstract
The Cretaceous Sandstones in Nannilam Field of Cauvery Basin, have a few significant hydrocarbon reservoirs. In general, Upper Creataceous Sandstones are good quality reservoirs with mostly intergranular and interconnected dissolution pores while Lower Cretaceous Sandstones are low-quality reservoirs with mostlymicropores and a few interconnected pores.
Evolution of Inter-Montane Kargil Basin (Oligo-Miocene), Ladakh Himalaya: A Sedimentological Approach
Authors: Kumar Rohtash , Virdi N. S. 
Published: November 2024

Abstract
Sedimentation pattern, palaeocurrent data and architectural elements indicate that deposition took place in three stages. The first stage (Kargil Formation) was dominated by alluvial fan to distal braided streams flowing over northeast and east directed palaeoslopes. The second stage (the Tharumsa Formation) involved deposition initially by gravelly braided to sandy braided and finally by distributary channels flowing due SW and south. The third stage (the Pashkyum Formation) showing an upward coarsening sequence occurred initially by braided channels followed by prograding alluvial fans in the north and portheast directions. Sedimentation during the Kargil and Tharumsa formations was accompanied by episodic tectonic upheavals along the western and eastern margin, while the Pashkyum indicates a gradual uplift towards the southern margin of the basin.
Dugwell Inflows from Shallow Deccan Basalt Aquifers
Authors: Kulkarni Himanshu , Deolankar S. B. 
Published: November 2024

Abstract
Inflow conditions represent an important aspect of dugwell drawdown and recuperation in shallow Deccan basalt aquifers. "Inner" boundary conditions like well storage, connection between the well and aquifer and distribution of inflow zones representing the hydraulic conductiviy around dugwells can be deciphered from drawdown and recovery data of dugwells tapping a typical shallow phreatic aquifer from the Deccan basalts. It is possible to calculate the aquifer response of a dugwell during drawdown and recovery phases. The inflow conditions in dugwells and their effect on the drawdown and recovery can be well illustrated by plotting well logs alongside single logarithmic graphs of drawdown and recovery against time. Diagnosis of such graphs reveals how the hydraulic conductivity around the dugwell influences segments of the drawdown and recovery of dugwells.
Analyses of Ground Magnetic Anomalies Over a Part of Vindhyan Basin around Damoh and Jabalpur Districts, Madhya Pradesh
Authors: Singh V. P. , Singh O. P. , Singh C. L. 
Published: November 2024

Abstract
Detailed ground magnetic survey over a part of the Vindhyan basin around Damoh and Jabalpur (40 km either sides of Hirapur-Mandala DSS profile) has been carried out. The magnetic field anomaly map is characterised by dense contours in trap covered areas near Jabalpur where as the Vindhyans show sparsely distributed contours with several lows. Spectrum analysis of total ground magnetic field anomalies reveals the average thickness of Vindhyans to be 3.9 km and depth of Conrod to be 15km. The average thickness of Vindhyans is in conformity with the Deep Seismic Sounding results of the region. The thickness of Vindhyan sediments along four profiles ranges from 1.5km to 5km. The maximum thickness of Vindhyan sediments at Jabera has been derived to be 4.8km which is close to the results of Oil and Natural Gas Corporation Ltd., Dehradun.