bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of Heavy Minerals in Parangipettai (Porto Novo) Beach, Tamil Nadu
Authors: Mohan P. M. 
Published: November 2024

Abstract
Studies on the sediments of Parangipettai (Porto Novo) beach and its surrounding environments (Vellar river, estuary and nearshore environment) reveal that all the environments show texturally different characters but similarity in heavy mineral assemblages with varying percentage of occurrence. The river sediments are coarser (1.48 f) and moderately sorted than estuarine sediments which are finer (4.22f) and poorly sorted. The beach sediment; fall in the size range 2.25f to 2.61f in the southern region and 2.56f to 2.71f in the northern region, and are well to moderately sorted. In nearshore, sediments of the northern region are finer (3.50f) and poorly sorted than those of the southern region, which are coarser (2.98f) and moderately sorted. Sediments of river, bermcrest and backshore of southern beach and bermcrest of northern beach represent near symmetrical skewness and the other remaining beach environments have coarse skewness. Nearshore and estuarine sediments register fine and strongly fine skewed nature. In all the environments, the sediments are leptokurtic except those at low water mark of southern region where they are platykurtic. These variations are due to the physico-chemical conditions, impact of tidal action and longshore movements on the different environments. Conspicuous changes are noticed in the individual heavy mineral concentrations. Based on the mineral assemblage in the riverine environment, it is inferred that the main so~rces for these minerals are the rock types present in the catchment area of the river. The enrichment of some heavy minerals in the beach and nearshore environments suggest that the increment may be due to the addition of these minerals from some other sources like paleo sediments and the present day offshore sediments.
Micromammal-Based Palaeoenvironment of Upper Siwaliks Exposed Near Village Saketi, H. P.
Authors: Patnaik Rajeev 
Published: November 2024

Abstract
Two sections, namely Kanthro and Moginand exposing Upper Siwalik rocks near village Saketi (H.P., India) have yielded a diverse fossil assemblage and evidence for pedogenic modifications. Palaeoecological reconstruction indicates the presence of atleast four palaeocommunities (pond, pondbank, bushland and grassland). Studies concerning taphonomy reveals that there was a gradual accumulation of micro and megafossil remains in shallow seasonal ponds of broad flood plains. It is also noticed that the concentration of some small mammal remains were due to biogenic processes.
New Occurrence of Dinosaur Eggs from Lameta Rocks (Maestrichtian) near Bagh, Madhya Pradesh
Authors: Joshi A. V. 
Published: November 2024

Abstract
New occurrence of well preserved in situ dinosaur eggs have been found in the Lameta rocks, exposed in the vicinity of Bagh village in Dhar district, Madhya Pradesh. In all, three in situ eggs have been recovered, which are spherical in shape having a maximum diameter of 18 cm. The field occurrence and the morphological characters of these eggs, reveal their close affinity towards the sauropod group of dinosaurs.
Petrography and Petrochemistry of the Cordierite Bearing Metapelites of Nartamalai Area, Pudukkottai District, Tamil Nadu
Authors: Nathan N. P. , Sundara Raghavan S. , Natarajan V. , Raman R. 
Published: November 2024

Abstract
Occurrence of cordierite bearing metapelites of Khondalitic suite of rocks is reported from Nartamalai area, Pudukkottai district for the first time. The cordierite bearing gneiss occurs in close association with chamockite and pyroxene granulite in the vicinity of the Nartamalai granites. The mineral assemblages seen in the metapelites are cordierite-almandine-sillimanite-plagioclase-K-feldspar- biotite and quartz. Zircon, magnetite and spinel are the accessory minerals. The texture of the metapelites is generally gneissose except in the eastern part of the area where it simulates a hornfels. The Nartarnalai cordierite contains 59% Mg-cordierite and 41 % Fe-cordierite. The Fe+2/Fe+2+Mg ratio of the Nartamalai cordierite is 0.414 which is strikingly higher than that of the cordierites of regional metamorphism and it is comparable with the Fe2/Fe+2+Mg ratios of the cordieritcs described from hornfels assemblage. The coexisting garnet is an almandine-pyrope with very minor andradite and spessartitc, which is comparable with the garnets of regional metamorphic assemblage. The tie-line joining the composition of the coexisting cordierite and garnet indicates a regional metamorphic environment. An overprint of thermal metamorphism, attributable to the intrusion of Nartamalai granites, on the pre-existing regional metamorphic fabric is suggested.
Relicts of Sedimentary Precursors in Archaean Gneisses : Melukote Paragneiss -An Example from Dharwar Craton, India
Authors: Uday Raj B. , Naqvi S. M. 
Published: November 2024

Abstract
Relicts of sedimentary precursors in the Peninsular Gneisses around Melukote-Katteri area ofDharwarCraton are recognised on the basis of field, petrological and geochemical data. The Melukote gneiss has interbeds of carbonates, quartzites. iron-formations and para-amphibolites with a concordant planar fabric. These gneisses are devoid of mafic-ultramafic xenoliths which are one of the essential characteristics ofthe orthogneiss component of Peninsular Gneiss (PG), The Melukote paragneiss (MG) contains interstitial calcite, relict arkosic texture, subrounded to round quartz, plagioclase and zircon. Two generations of quartz and plagioclase are conspicuous in the MG. The MG are high SiO2 and low Al2O3 Cr and Ni are significantly enriched - up to 334 ppm and 73 ppm respectively. The Rb and Sr contents are lower than the typical tonalite-trondhjemite gneisses (TTG). The high HREE patterns of MG and very low negative Eu anomalies are distinct from those of TTG in the surrounding areas. These data indicate that MG represent first cycle immature sediment derived from a heterogenous provenance.
Sedimentology of Quaternary Alluvial Deposits of the Gandak-Kosi Interfan, North Bihar Plains
Authors: Sinha Rajiv 
Published: November 2024

Abstract
An account of sedimentolpgical characteristics such as grain size distribution, clay mineralogy, sand mineralogy and magnetic susceptibility of the alluvial sediments from the Gandak Kosi interfan area in the Indo-Gangetic plains of north Bihar is presented. Fine-grained sediments consisting of significant percentage of detrital clays and variable carbonate content are present in the plains and are distinctly derived from the Himalaya. Sedimentation in the interfan is episodic through overbank flooding forming thick muddy sequences. Changes in depositional regime occurred because of shifting of channels which, in turn, affected channel proximity of floodplain sites.
Occurrence of Ultramafics of Komatiitic Affinity in the Rikhabdev-Dungarpur Belt, Udaipur and Dungarpur Districts, Rajasthan
Authors: Gathania C. R. , Chattopadhyay A. K. , Sharma B. , Ameta S. S. , Ghosal A. K. 
Published: November 2024

Abstract
Preliminary study of the ultramafic suite of rocks emplaced concordantly in the Proterozoic supracrustals of the southern Rajasthan (Aravalli Supergroup) indicates their komatiitic nature. Though the diagnostic spinifex texture is not observed in the highly serpentinised and metamorphosed ultramafics, the amygdaloidal structure and the previously reported igneous joints provide textural evidences for the extrusion of the ultramafic lava. The altered ultramafics still retain certain chemical signatures (high MgO and Mg-No., low Ti02, Al2O3and alkalis) of standard komatiites.
Mineral Composition and its Bearing on Depositional History of Banded Iron-Formation of Kudremukh Schist Belt, Karnataka
Authors: Khan R. M. K. , Nirmal Charan S. , Arora M. , Naqvi S. M. 
Published: November 2024

Abstract
The iron-formations ofKudremukh mainly contain magnetite, recrystallized chert, gruneritecu mmingtonite (XMg 0.21 to 0.33), hornblende, bioti te along with minor amounts of ankerite (XMg O. 30 to 0.52), calcite (XMg 0.06 to 0.22), chamosite and pyri teo Chamosite, a rare relict mineral, was probably formed by reaction between high Al-clay and Fe. Magnetite was formed during metamorphism. Along with the precipitation of alternating layers rich in silica and iron, clayey material in the form of montmorillonite, illite and/or glauconite along with Fe-Mg carbonates were also deposited, which after metamorphism (430-520°C) gave rise to the present mineralogy.
Rb-Sr Age of the Metaluminous Granitoids of South Khasi Batholith, Meghalaya : Implications on its Genesis and Pan-African Activity in Northeastern India
Authors: Panneer Selvam A. , Prasad R. N. , Dhana Raju R. , Sinha R. M. 
Published: November 2024

Abstract
Metaluminous granitoids of the South Khasi batholith (SKB) in the West Khasi Hills district of Meghalaya define a Rb-Sr whole-rock isochron age of 757 ± 60 Ma, with (87Sr/86Sr) of 0.71069 ±0.00092. SKB and other granitoids of Meghalaya like Mylliem, Nongpoh and Kyrdem have many common features such as the presence of basic enclaves of hornblende gneiss and amphibolite, lateto post-tectonic nature, predominance of biotite amongst mafic silicates, overall metaluminous nature and high (87Sr/86Sr) of more than 0.709. All these indicate much similarity in the genesis of their melts due to partial melting of lower crustal rocks. The Rb-Sr isochron ages of SKB and other granitoids in Meghalaya point to a major tectonomagmatic activity during ca. 760-480 Ma, which is almost coeval with ca. 800-500 Ma Mid-Upper.Pan-African activity. The data, thus imply the possible imprint of the widespread Pan-African activity in northeastern India, besides southern India.
Cretaceous - Paleocene Carbonate Microfacies of Tamil Nadu and Pondicherry
Authors: Guha Asit K. , Mukhopadhyay T. J. 
Published: November 2024

Abstract
Nine types of Standard Microfacies (SMF) are identified in the Cretaceous-Paleocene carbonate sequences of the Ariyalur-Vridhachalam of Tamil Nadu and the Pondicherry areas. Of these four SMFs occur frequently.
The recurrence of SMF types within FZ 7 in successive fonnations of varying thickness indicates multiple transgressive - regressive episodes of unequal areal extent and time interval. A gradual decrease in the number of microfacies types in carbonate lithologies younger than the Turonian suggests progressive stabilization of the shelf. Presence of similar SMF in younger carbonate layers belonging to different areas and ages point to their being time-transgressive lithologic units. The carbonates are of low-Mg calcite variety. Significant depletion of Sr and Na and enrichment of Ba, K and Mn took place due to prolonged diagenetic alteration by meteoric water.
Geotectonic Model of Cambay Basin for Hydrocarbon Exploration from Mature to Immature Stage Using Fractal Geometry
Authors: Singh Ravi Pratap , Pati Prabhash Bihari 
Published: November 2024

Abstract
Geologic processes like structural evolution, sedimentation pattern, fluid distribution are non-linear and therefore, are expected to display chaotic characteristics evidenced by self-similar observations or fractals. A major characteristic of fractal geometry - the invariance of the observations with the scale is used to derive an empirical geotectonic model for the evolution of Cenozoic Cambay Basin and hydrocarbon exploration in it from mature stage to immature stage. The model comprises of two distinct tectonic phases of Paleocene-Early Eocene age and Mid Miocene age separated by a 'Transitional' shallow water sedimentation cycle of Middle Eocene-Early Miocene age. The boundaries of these phases are marked by frequently conspicuous angular unconformities. Most of the seismic energy is absorbedlrenected within these transitional sediments which has restricted hydrocarbon exploration to the Mid-Eocene reservoirs (Kalol-Kadi, Hazad-Ankleswar Fonnations). These are the easy-to-find accumulations and exploration in these sequences is now considered to be in mature stage with dwindling size of new prospects. Need has arisen to look for other prospective reservoirs in the deeper sequences particularly in Paleocene - Early Eocene (Olpad Fonnation) after establishing good source rock potential in it. The presence of hydrocarbons is already established in this sequence but it has remained almost unexplored due to lack of sufficient subsurface data and clear understanding of the tectonics. The model helps in forecasting economic prospects within this sequence in which the configuration of the prospects will be unlike to that of the already known 'conventional' plays of Mid-Eocene age. All the discoveries in this sequence are interestingly fitting well with this model. Moreover the model can be applicable to further deeper sequences as well in other basins like the Bombay offshore, Assam-Arakan and Rajasthan etc. because the analyzable element 'reversal of highlands and lowlands between two tectonic phases' is also observed there on various scales.
Application of Finite-Difference Method in Modelling an Oil Bearing Structure
Authors: Rathor B. S. , Devanandam M. , Mallick K. 
Published: November 2024

Abstract
Finite-difference numerical technique has been in use for over two decades in solving elastic wave equation for the interpretation of seismic response of complex 2-D and to a limited extent, 3-D oil bearing geological structures. The present communication consists of two parts. In the first part, synthetic seismograms have been obtained under plane wave as well as line source excitations for a gas cap structure and over a salt dome/basement undulation. In the second part, seismogram under plane wave conditions has been computed for a geological structure from the Gujarat coast. Some of the faults confining the pay zone between 1800 ms and 1900 ms in the time section are highlighted.
Tidal Cyclicity in Lower Bhander Sandstone, Maihar, Madhya Pradesh
Authors: Basumallick S. , Sarkar B. C. , Banerjee S. 
Published: November 2024

Abstract
The Upper Proterozoic Lower Bhander Sandstone, occupying a major part of the Tamasa valley at Maihar, has been thought to be deposited in a tidal flat-lagoon complex,in an intertidal to supratidal environment, dominated by ebb and flood tides. A tidal bundle (a medium grained thicker sandstone unit and a thinner siltstone bed) is thought to bear the imprint of velocity and discharge associated with each tidal current as reflected in the thickness of the layers. Thickness data pertaining to 155 tidal bundles recognized in the exposures have been analysed using techniques of Smoothing, Autocorrelation and Fourier filtering, to reveal whether or not any tidal cyclicity existed. The results amply support not only the presence of alternating high spring-neap-low spring semi-lunar cycles, but a dominant periodicity of 32 bundles corresponding to 16 semi-lunar days.
Study of the Aftershock Activity and Source Parameters of the Latur Earthquake of September 30, 1993
Authors: Ramakrishna Rao C. V. , Solomon Raju P. 
Published: November 2024

Abstract
A total of 45 stations were operated by different agencies to record the aftershocks of the september 30, 1993 Latur earthquake. In the present study 220 aftershocks were located using the combined data set. Most of the epicentres follow the course of river Tirna and confined to area of 10 km radius. To homogenise the estimation of magnitudes an empirical relation for estimating magnitude from signal duration, Ms = -1.6757 ± 1.9484 log D, is derived, where Ms is the surface wave magnitude and D is the total signal duration in sec. The magnitudes can be estimated with an accuracy of + 0.24 units using the above relation, Focal mechanism solutions for six aftershocks are reported in this study. The majority of the solutions are in agreement with the solution of the main shock. The pressure axis as determined from the focal mechanism solutions of the aftershocks is oriented along NE - SW direction.
Structure, Tectonics and Associated Ore Deposits of Subansiri District, Arunachal Pradesh, Eastern Himalaya
Authors: Kumar Surendar , Singh Trilochan 
Published: November 2024

Abstract
The geological setting of the Subansiri District is mostly controlled by the fold belt, a steep sided anticlinorium in the Quartzite - Phyllite Unit of the Bomdila Group that possibly overlies an Older Massif and a concealed deep seated fault. Amongst the economic minerals and are deposits, limestone, dolomite, coal, graphite, and various base metals are of great intetest. Beside these, sulphide mineralisation is quite common. Mainly four controls on the mineralisation have been recognised, which are:
1. Deposits are strata-bound within the Phyllite - Quartzite Unit of the Bomdila Group and the Quartzite Unit of the Miri Group.
2. Ore occurs mostly near the thrust contact zone.
3. The deposits in rocks of both the units are located near the gneissic contact of the Bomdila Group as well as that of the crystallines of the Se La Group.
4. The Pb-Zn, Fe & S in the Bomdila Group show pockets and pinch and swell structures indicating earlier deposits subjected to erosional processes in the earlier phases.
Other deposits are in the Quartzite Unit of the Miri Group which are located close to the crystalline thrust.
Proterozoic Kaimur Group, Son Valley: Fluvio-Marine or Fluvio-Lacustrine?
Authors: Bhattacharyya Ajit 
Published: November 2024

Abstract
The Kaimur Group of the Vindhyan Supergroup in Son Valley is represented by a 8 to 400 m thick siliciclastic sequence covering an area of around 12,000 sq.km. Following the reinterpretation of the Dhandraul Sandstone (the uppennost unit of the Kaimur Group) as deposits of braided ephemeral river, punctuated by aeolian deposits, the long-prevailing shallow-marine interpretation of the sub-Dhandraul sequences has been reexamined. The sub-Dhandraul sandstones and shales reveal that their deposition took place at different depths in a large lacustrine basin affected by fair-weather as well as storm waves.
Sulfur Isotope Variations in Barite and Pyrite of Hydrothermal Barite Deposits of Cuddapah Basin, Andhra Pradesh
Authors: Mukherjee Abhijeet , Ballurkar Ashok 
Published: November 2024

Abstract
The d34S X-CDT values for barite and pyrite range from +23.6 to +25.5 per mil and -0.9 to +1.9 per mil respectively. Data of fluid inclusion studies enable temperature of deposition to be 250°C after pressure correction of homogenization temperatures (Th). The d34S X-CDT values of pyrite and barite suggest igneous source for pyrite and marine for barite implying that they are not formed together. The d34S X-CDT values of barite agree with d34S X-CDT values for contemporaneous Proterozoic sea water.
Mechanism of Microseismic Activity in Kerala - A Suggestion
Authors: Rajendran Kusala , Rajendran C. P. 
Published: November 2024

Abstract
The occasional incidences of microearthquakes in Kerala have been interpreted to be caused by the reactivation of ancient preexisting faults. While not negating the traditional wisdom, we propose an unconventional approach to analyze the mechanism of microseismicity in Kerala. A moot point considered here is the perceptive increase in the frequency of the microearthquakes in the state over the last decade, quite often coinciding with periods of increased rainfall. Although the occurrence of rain may not be a sufficient or necessary condition for the increase in the level of seismic activity, the correspondence between the two appears to be more than casual. On the basis of this observation. we suggest here that the tremors in Kerala may have been caused by transient increase in the hydrostatic pressure at shallow crustal depths. The mechanism of shallow earthquakes may be similar to what is proposed in the "hydroseismicity" model. Changing land use patterns, deforestation, soil erosion and increased siltation in the drainage basins are the robust parameters in this model.
Integrated Foraminiferal and Ammonoid Biostratigraphy of Jurassic Sediments in Jaisalmer Basin, Rajasthan
Authors: Dave Alok , Chatterjee T. K. 
Published: November 2024

Abstract
In the Post-Vindhyan times, major marine transgressions covered the areas of Kutch and Rajasthan, including the Jaisalmer Basin during Jurassic, although minor Permian transgressions are also known. These events could be documented from the well known exposures of Kutch and Rajasthan which entombed classic Cephalopod fauna. The foraminiferal components of Kutch Mesozoic were catalogued by Pandey and Dave (1993), recognizing 13 benthic foraminiferal biozones, establishing 8 chronostratigraphic units (stages).
Within the outcropping marine Middle-Upper Jurassic succession of Jaisalmer, seven benthic foraminiferal zones have been recognized and correlation with Kutch Mesozoic established. However, the succession is interrupted by five hiatuses during - (1) Upper Bathonian, (2) Upper Callovian - Lower Oxfordian, (3) Upper Oxfordian - Lower Kimmeridgian, (4) Middle Kimmeridgian and (5) Upper Kimmeridgian - Lower Tithonian.
Trangressive events during Lower Bathonian, Lower Callovian, Middle - Upper Oxfordian and Lower Kimmeridgian with intervening regressive pulses are also recorded.
Badian, Charian, Dhosaian, Katrolian and Umiaian stages of Kutch ranging in age from Bathonian to Tithonian are recognized.
Origin of Amphibole-Rich Beach Sands from Tila-Mati, Karwar, Central-West Coast of India
Authors: Mislankar P. G. , lyer S. D. 
Published: November 2024

Abstract
The pocket beach at Tila-Mati, Karwar, central west coast of India, is characterised by the occurrence of amphibole-rich (chiefly tremolite-actinolite) coarse sand in the zone of minimal impact of waves and currents.
In the total sediment, grain size and sphericity are directly proportional while a decrease in sphericity results in an increase of amphiboles (60-80%). This is probably due to the elongated nature of the amphibole grains which are abraded in a low energy environment. The Tila-Mati beach sediment has been derived locally by erosion of amphibole schist exposed in a cliff adjacent to the beach.
Orbicular Structures from Lingsugur Area, Raichur District, Karnataka
Authors: Prakash H. S. M. 
Published: November 2024

Abstract
Well developed single shell orbicules and proto-orbicules with hornblende as the nucleus and plagioclase as the shell, are well preserved in a 30 m x 11 m outcrop of diorite at jalibenchi, Lingsugur area, Raichur district. It could also be described as esboitic as the feldspar is oligoclase. The normative anorthite content in the orbicule varies from 26.13% to 33.64%. The solidification indices are low suggesting a slow but steady rate of cooling. The chemical and mineralogical discriminant diagrams show that the orbicular rocks are tonalitic to mafic tonalitic in composition. The two units of the orbicular structure viz., (1) the core made up of hornblende is attributed to have been derived from an enclave of amphibolite which was invaded and shattered by an upwelling hydrous pegmatitic plagioclase vein and gel-like in nature and acted as the cause for the formation of the (2) single shell structure. The monomineralic composition of the shells of orbicules and the unicomponent composition of the plagioclase vein are thus genetically explained.