bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occurrence of a Manganese-Bearing Horizon in the Kaladgi Basin
Authors: Pillai Shilpa Patil , Peshwa V. V. , Nair Sushma , Sharma Mukund , Shukla Manoj , Kale Vivek S. 
Published: November 2024

Abstract
A manganiferous horizon was recorded near Niralkeri, in an intricately folded quartzite-chert breccia-mudstone sequence of the Simikeri Subgroup in the Kaladgi Basin of Karnataka. The nodules collected from this horizon show the presence of todorokite, vemadite and lithophorite in association with quartz and hematite; with MnO-58%.
Elemental Composition of Damodar River Sediments - A Tributary of the Lower Ganga, India
Authors: Singh Abhay Kumar 
Published: November 2024

Abstract
Bed, suspended and core sediments collected from the entire region of the basin were analysed to determine the elemental chemistry of the sediments of the Damodar river basin. The analytical results show that bulk sediment chemistry consists mostly (&gt;75%) of five elements, Si, Al, K, Fe and Na. Mean composition has indicated that the Damodar sediments are depleted in Ca, Mg and heavy metals and enriched in Si and K as compared to the other Indian river basins. The concentrations of heavy metals in the suspended sediments are significantly higher than the bed sediments. In general, heavy metal concentration increases towards the finer size fractions. The depth variation of heavy metals in the core sediments shows no specific trend. Speciation studies show that the lithogenic phase is the major sink for heavy metals. Fe-Mn oxide and organic fractions are the major nonlithogenic phases and Zn is the major constituent of the nonlithogenic phase. Geoaccumulation indices calculated for Fe, Mn, Cu and Zn indicate that Damodar sediments are not polluted with respect to these metals.
Ophiuroid ossicles from the Kallankurichchi Formation (Maastrichtian) of Ariyalur Group, Tamil Nadu, India
Authors: Mallikarjuna U. B. , Sugumaran S. , Nagaraja H. M. 
Published: November 2024

Abstract
This paper reports the finding of ophiuroid ossicIes in the Kallankurichchi Formation (Maastrichtian) of Ariyalur Group, Tamil Nadu. The material is rather ill preserved and represents indeterminate vertebrae, dorsal shields, possible genital bars and some questionable material of uncertain affinity. The palaeoecological implications of these ossicles on the Kallankurichchi Formation are discussed.
Allogenic Control on Late Quaternary Continental Sedimentation in the Mahi River Basin, Western India
Authors: Malik J. N. , Khadkikar Aniruddha S. , Merh S. S. 
Published: November 2024

Abstract
The late Quaternary continental succession exposed along the cliff-like banks (15-35 m) of the Mahi river basin comprises sediments of fluvial and aeolian origin and provides an opportunity to assess palaeoclimatic changes in western India. Seven different facies are recognized in the exposed sediment succession. The trough cross-stratified conglomerates (Gt) formed due to downstream migration of trains of sinuous-crested dunes in shallow channels, whereas the formation of planar cross-stratified gravels (Gp) is attributed to downstream accretion of the avalanching front of a mid-channel bar, The horizontally stratified sands (Sh1 ) represent overbank deposits, while similar facies (Sh2 ) owes its origin to infrequent sheet flooding events. The trough cross-stratified sands (St) appear to be a product of low-stage river processes. The 'loess-like' massive silts (Sim) are of aeolian origin. The calcic palaeosol facies (P) are represented by vertisols at the base and brown soils and calcic red soils towards the top indicating changing palaeoenvironments.
The overall sediment succession was built through three major climate-controlled aggradation phases. Aggradation phase 1, which is represented by gravel-bed rivers and coexistent vertic palaeosols, indicates a significantly wetter climate. Aggradation phase 2 points to a comparatively drier period during which suspended-load rivers existed. Within this phase, red soil formation suggests a climatic amelioration event around 40 ka B.P. to 23 ka B.P. Aggradation phase 3 reflects a period of extreme aridity and is manifested as the capping aeolian facies. This phase is thought to be in tandem with the Last Glacial Stage event. Stabilization of these dunes may have taken place around 6 ka B.P. as suggested by the Thar Desert palynological and lake records.
The modern Mahi channel flows due ssw. However, the palaeocurrent trends of the exposed sediment bodies reveal that the ancient drainage network in the northern sections (upper reaches) flowed due SW-SSW and in the southern sections (lower reaches) SSE, SSW and W. The present day course of Mahi is relatively younger and follows structural lineaments that developed during the Holocene (after 6 ka B.P.). The aIluvial sedimentation record is unrelated to the modern Mahi river, but is a product of ancient late Quaternary rivers which now stand either fully or partially destroyed.
Significant Inferences on Deep Crustal Structure of Deccan Trap Region from Spectral Analyses of Bouguer Anomalies
Authors: Pant P. R. , Agarwal B. N. P. , Choudhury K. , Dasgupta S. P. 
Published: November 2024

Abstract
Qualitative interpretation of the regional Bouguer anomaly map of the Deccan Trap region of peninsular India, based on the anomaly size, its gradient and minor contribution from the shallow crust assessed by the results of other geophysical methods, suggests that the major part of the these anomalies have deep seated origin with 'lows' corresponding to the zones of subsidence and 'highs' to the uplifts involving the crust. Deep faults along the west coast and segmented faults demarcating the Narmada rift valley and Narmada-Son Lineament (NSL) have been delineated. Spectral analysis, matched filter technique for deconvolving gravity effect of sources at a particular depth and a single interface gravimetric inversion scheme have been utilised to delineate density discontinuities and their 3D configurations. The deconvolved gravity effect due to the deepest density interface at a mean depth of 117 km seems to reflect lithospheric variations and is used to distinguish the stable crust from the metastable one. The Moho relief map, apart from structural features, exhibits a good agreement with the results by Deep Seismic Sounding (DSS) in Koyna area and across NSL.
The block-wise analyses reveal higher average depths to Moho and Conrad, which are typical of stable shield crust, in the southern part whereas the northern blocks associated with rift tectonics exhibit considerably thin upper crust (5.8 to 12.6 km) with another crustal interface at a depth in the range of 16.3 to 26.8 km. The latter depth forms the base of the middle crustal layer i.e., top of the lower crustal layer comprising lower mantle derivatives. These inferences are based on the correlation between Bouguer anomaly and upper crustal thickness and layered velocity structure brought out by DSS data across the NSL. Filtered Bouguer anomaly maps have further facilitated the interpretation and better demarcation of structural features inferred from qualitative interpretation.
Mineralogy and Isotopic Composition of Pyrites-Bearing Ejects from a Mud Volcano, Baratang, Andaman Islands
Authors: Achyuthan Hema , Eastoe Chris 
Published: November 2024

Abstract
The Jarawa Creek mud volcano on Baratang Island has produced a variety of ejecta including mud containing illite, kaolinite and microfossils, volcanic glass, brine, methane gas and sulfide nodules. The nodules are of pyrite with a d34S ranging from -3.6 to 25.4‰. Sulfate leached from the mud has d34S values of -9.3 and -11.37‰. Our study reveals that the sulfate could not have been derived either from the nodules themselves or from the sea water or from connate brine. The nodules are of sedimentary origin and the most likely source of sulfate is sedimentary sulfide implying subsurface oxidation and a supply of oxidant possibly in groundwater.
Geology of Mumbai and Surrounding Areas and its Position in the Deccan Volcanic Stratigraphy, India
Authors: Sethna S. F. 
Published: November 2024

Abstract
Field data reveal that the lava flows in Mumbai and surrounding areas erupted after the rifting of the main plateau basalts of the Deccan Volcanic Province. Majority of the lava flows occur as subaqueous lavas forming hyaloclastites, spilitic pillow lavas and partially subaqueous and subaerial flows. The basic lavas are associated with rhyolitic flows and contemporaneous intrusions of basic and trachytic magmas forming hybrid rocks of monzonitic and dioritic variety. It has been shown that petrochemically the basic magma of the area is very different from the magma types associated with the mainland horizontal flood basalts ofthe Deccan Volcanic Province. The basic rocks of the Mumbai-Salsette area show lower concentrations of Cr, Ni, Y, V and Ti; and higber concentrations of K, Rb, Ba, Zr and Nb. Majority of these samples contain similar concentrations of phosphorus except for three Salsette samples which show unusual high values. The volcanics of the Mumbai-Salsette area are classified as forming the Salsette Subgroup with three Formations viz., Mumbai Island, Madh-Utan and Manori.
Evidence for Pre-Grenvillian High-Pressure Granulite Metamorphism from the Northern Margin of the Sausar Mobile Belt in Central India
Authors: Bhowmik Santanu Kumar , Pal Taraknath , Roy Abhinaba , Pant N. C. 
Published: November 2024

Abstract
Distinct lithological associations, structural relationships, and petrographic and geothemobarometric results indicate the presence of reworked granulites of Pre-Grenvillian age from the northern margin of the Sausar mobile belt (SMB) in Central India. In rare residual zones, the mafic granulite-felsic migmatite gneiss association preserves early structures and high-P (~ 10.5 kbar at ~ 775°C) granulite histories which appear to pre-date and bear no relation to ~ 1000 Ma old Sausar orogeny. An isothermal decompression through ~ 5.5 kbar at 750°C from maximum recorded P-T condition, possibly signifies extensional collapse of the crust, previously thickened through collision. During the Sausar orogeny, the granulites were further tectonically interleaved with younger lithological associations. Widespread retrogression in amphibolite and finally in greenschist facies conditions have all but obliterated granulite mineralogy and structure except in rare low-strain domain.
Petrography and Geochemistry of the Radioactive Albitites and their Genesis: Maonda Area, North Rajasthan
Authors: Jain Rajan B. , Yadav O. P. , Rahman M. , Thippeswamy S. , Fahmi S. , Sharma D. K. , Singh Govind 
Published: November 2024

Abstract
A partly concealed radioactive alibitized pegmatoid/quartz albitite body (1200 m x 0.5 to 20 m) containing 0.010 to 0.190% U3O8 and 0.007 to 0.076% ThO2 and about 20 brick red coloured albitite lenses varying in dimension from 13 m x 7 m to 220 m x 12-30 m and containing 0.022 to 3.50% U3O8 and 2 are described at Banjaron Ki Dhani, new Maonda in north Rajasthan. Davidite, brannerite, rutile, anatase, zircon, monazite and traces of uraninite have been identified in the albitites. A metasomatic origin for the albitites is suggested. The distribution of albitites along NE-SW to NW-SE and E-W trending weak structural planes and the coincidence of 'Albitite Line' with Kaliguman lineament, demonstrates the tectonic control of albitization.
Precise 40Ar/ 39Ar Age Determinations of the Kotakonda Kimberlite and Chelima Lamproite, India: Implication to the Timing of Mafic Dyke Swarm Emplacement in the Eastern Dharwar Craton
Authors: Chalapathi Rao N. V. , Miller J. A. , Gibson S. A. , Pyle D. M. , Madhavan V. 
Published: November 2024

Abstract
40Ar/ 39Ar age spectra of groundmass phlogopite separates from the Kotakonda kimberlite (Eastern Dharwar craton) and the Chelima lamproite (Cuddapah basin) are dominated by major plateaus at 1401.4±4.6Ma and 1417.8±8.2 Ma respectively. These ages are consistent (within their error limits) with the conventional K-Ar dates on phlogopite separates from the same samples earlier reported by us. This study supports our contention that the emplacement of Kotakonda kimberlite and Chelima lamproite was contemporaneous and these pipes are older than the Anantapur kimberlites (-1090 Ma) of the Eastern Dharwar craton. The agreement of ages obtained by employing more than one technique is a testimony of confidence in our results and, therefore, firmly establishes an episode of Proterozoic mafic potassic magmatic activity in the Eastern Dharwar craton and adjacent Cuddapah basin at ca. 1400 Ma. The concordance of plateaus and correlation of isochron plots for both these bodies suggests that at least these parts of the Eastern Dharwar craton and Cuddapah basin have not been subjected to any subsequent tectono-thermal activity. Our results contrast with the recent suggestion that a ~ 1000 Ma thermal event in and around the Cuddapah basin led to argon loss and was responsible for the variable K-Ar ages of dyke swarms in the Eastern Dharwar craton.
Reworking of BIF into GIF in the Sandur Schist Belt, India: Possible Evidence of Sea Level Changes in an Archaean Proto-Ocean
Authors: Manikyamba C. 
Published: November 2024

Abstract
Granular iron formations (GIF) which are abundant in some Proterozoic, BIF bearing sedimentary basins are reported for the first time from the Archaean Sandur schist belt. These beds show lateral and vertical transition and repetition with oxide facies BIFs. Graded bedding and angular fragments are found in them. They consist mainly of iron and silicon oxides. Their trace clement and REE patterns itre similar to the BlFs from which they have been derived as a consequence of submarine erosion on the shelf through transgfession-regression cycles. Changes in sea level indicated by these structures were probably caused by volcanic activity and associated seismic tremors.
Geothermometry and Mineralogy of Two-Pyroxene Granulites: Evaluation from Mossbauer and X-ray Single Crystal Cation Partitioning of Ca-Poor and Ca-Rich Pyroxenes
Authors: Mitra S. , Princivalle F. , Samanta A. K. , Moon Hi-Soo 
Published: November 2024

Abstract
Fe-Mg ordering as well as Fe2+ and Fe3+ distribution at different sites in coexisting orthopyroxene and clinopyroxene determined by, Mossbauer spectrpscopy and X-ray diffraction (sample 6a), have been used in deciphering the thermal history of two-pyroxene granulites of Sittampundi Complex (India). Orthopyroxenes and clinopyroxenes are compositionally in the granulite field of metamorphism. For orthopyroxenes, the Mossbauer spectra show that Fe2+ is present at M1 and two different M2 sites, while Fe3+ is localised at M1 site alone. For the coexisting clinopyroxenes, Fe2+ occurs at both M1 and M2. Fe3+ is present only at M1 site, but in Ca-rich clinopyroxenes, under high fO2, conditions, it is seen to replace silicon in tetrahedral site.
From the distribution of Fe2+ - Mg, using Mossbauer data, the blocking temperature of intracrystalline ordering in orthopyroxene has been calculated to range between 427 and 699°C, in agreement with the estimated temperature obtained by means of X-ray data of about 500°C; in clinopyroxene it was 680°C as obtained from X-ray data. The recorded inter-crystalline ordering temperature was determined as between 661 and 785°C. The lowering of blocking temperature recorded by intracrystalline Fe2+ - Mg exchange suggests that the cation ordering in the M1 and M2 sites continued in the cooling path of the granulites below the temperature indicated by inter-crystalline distribution, and that the cooling (history) suffered by the host rocks was slow.
Fractal Analysis and Seismicity of Bengal Basin and Tripura Fold Belt, Northeast India
Authors: Sunmonu Lukman A. , Dimri V. P. 
Published: November 2024

Abstract
Northeast India experienced compressive forces from the Himalayan Arc in the north and the Burmese Arc in the east, which led to the development of a number of seismogenic faults, fractures and lineaments. It is observed that the characteristics of earthquakes occurring on an active fault are closely related to the irregularity of fault geometry. Because of their rough appearances over many length scales, faults can be conveniently regarded a. fractal sets, and their georretrical irregularity can be quantified using fractal dimension. We have calculated fractal dimension of the distribution of faults in two tectonic blocks, Bengal basin and Tripura fold belt, in the northeast India. We found that in the spatial sense the fractal dimension and the seismicity are positively correlated.
Quaternary Tectonic History and Terrain Evolution of the Area Around Bhuj, Mainland Kachchh, Western India
Authors: Thakkar M. G. , Mauryara D. M. , Raj Rachnar , Chamyal L. S. 
Published: November 2024

Abstract
The Mainland Kachchh has witnessed several phases of tectonic movements since the formation of Kachchh rift. The structural set up of the area is dominated by two fault systems - an E-W fault system which controls the geomorphic configuration and a NNW-SSE to NNE-SSW fault system which displaces the E-W faults. The Quaternary deposits of the area, alluvial and colluvial fans, channel deposits and miliolites help in categorising Quaternary tectonic activity into two phases. Reactivation of E-W trending faults during Early Pleistocene led to the present landscape configuration and formation of extensive alluvial and coIluvial fans along these faults. The post miliolite phase resulted in movements along transverse faults as evidenced by a very youthful fault scarp morphology and faulting in postmiliolite alluvial sediments along this trend. The mountain front sinuosity values also suggest a younger phase of tectonic activity along the transverse faults. The first order topography and the seismic activity suggest continued tectonic instability of the region.
Palynology in Hydrocarbon Exploration - Advancements in Indian Perspective
Authors: Mehrotra N. C. , Kapoor P. N. 
Published: November 2024

Abstract
Palynology plays an important rote in cost effective exploration and exploitation of hydrocarbons. It consists of study of spores, pollen, dinoflagellate cysts, diatoms, nannoplankton, silicoflagellates, radiolaria, chitinozoa, algae and other organic remains.
Study of spore, pollen, dinoflagellate cysts and nannoplankton help in precise dating of sediments, marking of hiatuses and correlating surface and subsurface samples by giving absolute ages in million years. Source rock study helps in visual typing of kerogen, quantitative assessment of organic matter, paleoenvironment and palynofacies interpretation. Spectral analysis gives precise thermal maturation levels. The integration of source rock parameters helps in deciphering source rock potential facies. Correlation of burial history curves with the source rock potential facies helps in the determination of time and duration of hydrocarbon generation. Examples from different sedimentary basins emphasizing the role of palynology in hydrocarbon exploration are cited.
The biozonal comparisons and absolute pollen frequency (APF) values are being used for interpreting transgressive - regressive cycles. Paleogeographic maps can be reconstructed with palynological data. The chronostratigraphical correlation with seismic stratigraphy is being attempted in geologically synchronous stratal surfaces. Palynological studies support basin analysis leading to stratigraphic evolution and hydrocarbon prospect analysis. They aIso help to build sequence biostratigraphy and delineation of reservoir sands for effective reservoir management.
Sulfur Isotope Geothermometry from the High Grade Metamorphosed Sulfide Deposit at Mamandur, Tamil Nadu
Authors: Chattopadhyay P. K. , Sarkar S. C. 
Published: November 2024

Abstract
Sulfur isotope geothermometric data obtained from the limited study of coexisting sphalerite-galena pair in the high grade metamorphosed Zn-Pb(-Cu) deposit at Mamandur, furnish a wide range of values, from 870° C to 255° C. While the Tmax closely matches with that from silicate geothermometry of adjacent rocks, some other data sets suggesting intermediate range of temperature are correlatable with a retrograde phase of regional metamorphism recorded in the silicates. The low temperatures however, are inconsistent with the silicate geothermometric data and may be taken to suggest resetting of equilibrium in the sulfide pair at lower temperatures without affecting the silicate pairs, as these temperatures were lower than the closure temperature of Fe-Mg partitioning in the latter.
Current Seismicity and Tectonics Near the Gulf of Cambay: Evidences for the Khambat Plume Induced Activity
Authors: Mukhopadhyay Manoj , Arora S. K. 
Published: November 2024

Abstract
The Western Indian shield is seismically active as shown by both historical seismicity records and recently acquired instrumental data. Moderate to large earthquakes have occurred in the region but they do not clearly correlate with known tectonic features or faults. Current seismicity for this part of the shield for the period 1977-97. as evidenced from Gauribidanur Seismic Array (GBA) data, is found to be largely restricted to an area of about 80 km radius which accounts for almost 85 percent of the activity. The area is referred to as the Surat-Daman Seismic Zone (SDSZ) which has a general correspondence to the regional pattern of seismicity over the Western Indian shield established from both instrumental and non-instrumental data for a longer time span. The Indian shield crust is known to exhibit a sharp reduction in crustal thickness from 36 km below the Cambay Rift to about 20 km below the SDSZ within a distance of about 70 km. The thin shield crust is dissected into several faulted blocks that arc deformed to various degrees; some of these crustal blocks are seismically active. These features suggest that seismic activity in the region possibly relates to the fossil trace of the Khambat Plume along the Western continental margin near the Gulf of Cambay. The fossil plume appears to be located at least 100 km eastward onland. Bouguer anomalies over the fossil plume are largely positive with amplitudes upto 130 mgal, rendering further support to the presence of anomalous crust in the region. Available stress data from focal mechanism solutions indicate compressive stress in east-west to NNE-WSW direction. This suggests that stresses responsible for rift tectonics are not significant at the present stage; rather, the plume tectonics seems to be regionally predominant.
Gold in Copper-Uranium Ores of Singhbhum Shear Zone, Bihar
Authors: Krishna Rao N. , Sunilkumar T. S. , Narasimhan D. 
Published: November 2024

Abstract
Nature of occurrence of native gold in the uranium ore from Jaduguda and copper ore from Mosabani in the Singhbhum Shear Zone, Bihar, is described. Preliminary data on the gold contents of different ore deposits along the shear zone, and their beneficiation products, are also reported. The native gold particles appear to be of detrital origin.
A Note on the Ostracode Fauna from the Jurassic Beds of Jumara Dome, Kachchh
Authors: Khosla S. C. , Jakhar S. R. 
Published: November 2024

Abstract
The paper records the occurrence of 28 species of ostracodes from the Jurassic beds of Jumara dome, Kachchh. Twenty-three species are assigned to previously established species, while 5 species are left under open nomenc1ature. All the species are illustrated.