bluuebunny/crossref_metadata_2025 huggingface dataset:
Ductile Shearing and Large-Scale Thrusting in the Main Central Thrust Zone, Chur-Peak Area, Lesser Himachal Himalaya
Authors: Mukhopadhyay Dilip K. , Bhadra Bidyut K. , Ghosh Tamal K. , Srivastava Deepak C.
Published: November 2024

In the Himalayan orogenic belt the rocks of the High Himalaya Crystalline Zone (HHCZ) have been thrust over the rocks of the Lesser Himalaya Zone along the Main Central Thrust (MCT). Around the Chur peak in the Lesser Himachal Himalaya the frontal part of the HHCZ is preserved in a half klippe. Analyses of structures from thin section to outcrop scales in this area show that a progressive ductile shearing has been superimposed on two generations of pre-shearing coaxial folds (F1 and F2 ). The F1 and F2 are tight to isoclinal and recumbent to gently plunging reclined/inclined folds with E or W axial trend. A penetrative cleavage (S1) parallel to the axial planes of F1 folds is the common planar structure, and a crenulation cleavage (S2) parallel to the F2 axial planes has sporadically developed. In the ductile shear zones the rocks have been extensively mylonitized and a plethora of small-scale compressional and extensional structures have developed. A set of very open and upright folds (F3) has affected all these structures. The last episode of deformation is represented by a set of subvertical fractures some of which are normal faults. Detailed mapping in selected areas and stereographic analyses of small-scale structures in the shear zones show that the earlier interpretation of large-scale recumbent folding on stratification is not tenable. Four large-scale thrusts cut up the crystalline rocks of the area into a pack of four thin thrust slices in large scale. The MCT in this area can be considered to be a 5-6 km thick ductile shear zone in which two phases of preshearing coaxial folding and late-stage thrusting can be demonstrated.
Local Gravity Anomaly and Geotectonics in the Dharamsala Palampur Area, Northwest Himalaya
Authors: Mahajan A. K. , Kumar Surendar , Chabak S. K.
Published: November 2024

Gravity survey in the station spacing of about 2 km was carried out in Dhararnsala-Palampur area (36 x 20 km) of the northwest Himalaya to study the seismotectonics of the region. The regional trend of Bouguer anomaly shows general decrease from -230 mGal to -250 mGal from south to north. The present gravity survey in DhararnsaIa-Palampur area has brought out some gravity highs trending transverse to the Himalayan trend. The presence of gravity high zone in the central portion of the study area near Yol may indicate either an anticlinal structure or emplacement of denser material from below, probably along the southeast dipping transverse feature noticed in the area. Another gravity high is noticed southwest of Palampur, also named as Paror anticline. The Bouguer anomaly map has helped to detect some transverse faults trending northeast-southwest and north-south i.e. oblique to the major thrust in the Dharamsala-Palampur region.
Multiple Deformation Around Saltora Murlu in the Western Part of Bengal Anorthosites
Authors: Dastidar S. , Samanta S. , Chaudhuri A. K.
Published: November 2024

Structural mapping in this area in Bankura district of West Bengal reveals coaxial easterlyl westerly plunging early isoclinal F1 folds and later upright F2 folds giving rise to hook-shaped interference patterns. Later slip and shearing along the F2 axial plane cause considerable bending of early linear structures in both mesoscopic and macroscopic scales. All rock types including anorthosite, granite gneiss and composite gneiss are affected by multiple deformation plan.
Striated Coal from Darjeeling and Rangit Valley Coalfields, Eastern Himalaya
Authors: Ghosh T. K.
Published: November 2024

Striated structure has been .recorded in some coal seams of Darjeeling and Rangit Valley Coalfields. This structure is generally restricted within the vitrain bands which range in rank from Iignitous to anthracite. The structure is fonned mainly due to brittle deformation with or without little rise in temperature.
A Curie Balance Using an Optical Motion Detector
Authors: Share J. A. , Sherwood G. J. , Bandyopadhyay G. , Das A. K.
Published: November 2024

A simplified design for a Curie balance incorporating an optical motion detector and personal computer is described.
Petrology and Geochemistry of the Lamprophyric Rocks from the Bokaro Coalfield, Bihar and their Economic Potential
Authors: Basu A. , Bhattacharya A. K. , Paul D. K.
Published: November 2024

The dyke swarms intruding the Gondwana sequence in the east Bokara Coalfield, Bihar include lamprophyres and lamproites such as olivine lamproties, olivine-leucite lamproites and leucite lamproites. Basic intrusives and rare siderite rich carbonates (carbonatite ?) are also found. The olivine lamproites contain xenocrysts of olivine and rare xenoliths of harzburgite. Gold values upto 3.6 ppm on grab samples have been noted from the intrusive rocks in the area. These lampropbyric rocks are considered to have formed from a highly incompatible element enriched metasomatised mantle source probably of harzburgitic composition.
Rubidium-Strontium Whole-Rock Ages of Banded and Incipient Charnockites from Southern Karnataka
Authors: Hansen E. C. , Stern R. J. , Devaraju T. C. , Mahabaleswar B. , Kenny P. J.
Published: November 2024

The Late Archaean regional amphibolite facies to granulite facies progression in southern Karnataka contains two textural varieties of charnockite (orthopyroxene-bearing quartzofeldspathic rocks). Banded chamockites typified by the banded pyroxene gneisses in the vicinity of Halaguru are thought to be older than the "incipient" coarse-grained charnockitic alteration of am.phibolite facies gneisses, as at Kabbaldurga, and similar alteration of the banded charnockites in many places south of there.

Whole-rock Rb-Sr isochrons were obtained for banded chamockites from the Chillapura quarry near Halaguru, and for incipient charnockite in amphibolite facies gneiss from a quarry near Honganuru, just east of Chamarajnagar. Large multi-layered samples and individual layers (light versus dark layers) were analysed separately in an attempt to discriminate older and younger metamorphic ages. For both quarries, all data yielded good isochrons with ages near 2.5 Ga, or terminal Archaean (2.50 ± 0.05 Ga with initial 87Sr/86Sr = 0.70500 ± 0.00009 for Chillapura and 2.54 ± 0.17 Ga, 0.7088 ± 0.0016 for Honganuru). More than one age of charnockitic metamorphism based on isotope systematics of samples collected from single quarries is not evident.

The high initial Sr ratios for both localities suggest, however, that the country rocks in southern Kamataka had a protracted crustal history prior to 2.5 Ga ago. Moreover, when the mean isotopic data of both quarries are plotted on the same diagram, "a regional isochron" close to 3.0 Ga with low initial Sr ratio results. This plausibly corresponds to a crustal accretion age, in accord with the interpretaiton of previous whole-rock isotope studies of this region based on combining data from widely-separated quarries. A widespread high-grade metamorphic event coinciding with, or following shortly after, crustal accretion remains an open possibility.
Occurrence of Anorthosite Near Sripuram, Khammam Schist Belt, Andhra Pradesh
Authors: Srinivasan K. N. , Ganesan V. , Roop Kumar D. , Murti K. S. , Rao N. V.
Published: November 2024

The anorthosite of Sripuram is a syn - to late - tectonic concordant intrusive into the rocks of Khammam Schist Belt (KSB). Its major element Chemistry is comparable to Archaean anorthosites.
Geological and Geochemical Studies on Carbonatites and Rocks of Carbonatitic (?) Affinity from Areas North of the Narmada Lineament in Madhya Pradesh and Gujarat
Authors: Khandelwal M. K. , Maithani P. B. , Pant P. C. , Hansda P. K. , Ramachandran S.
Published: November 2024

In the region covering some 400 km2 immediately to the north of Narmada lineament between Dharmrai, Dhar district, Madhya Pradesh, in the east and Nakhal and Panwad, Vadodara district, Gujarat, in the west, numerous E-W to ENE-WSW trending linear fault zones (c.l km to 5 km long X 20 m to over 100 m wide) occur within the Deccan basalts and infratrappean rocks. Brownish, brecciated, calcareous rocks, often with pockets and veins of calcite (carbonatites ?) are found within such fracture zones, and many of them show intrusive-like features. These faults apparently have developed sympathetic to the major Narmada rift to the south which provided structural avenues for the emplacement of carbonatites and associated basic alkaline rocks as found at Ambadongar. Panwad, Kawant and Saidiwasan, as part of the Deccan volcanic episode. Comparison of major and selected trace element data on these carbonatitic (?) rocks with Woolley and Kempe's average trace elements in carbonatite indicates that they are significantly impoverised in Zr, Nb, Y, La and U compared to the carbonatites and phonolites and phonolitic nephelinites of Panwad, Saidiwasan and Nakhal which are enriched in these elements. Carbonate-rich rocks of Bakhatgarh and Katarkheda in the east are rich in CaO and P2O3 compared to those of Panwad and Kawant. Based on available data it is suggested that the carbonatitic (?) types found in the east may represent an early phase of carbonatite (?) impoverished in Zr, Nb, Y, La, U and Th compared to the late residual (?) phase found in the Panwad-Saidiwasan-Nakal area which records significant radioactivity (upto 0.04% eUPR) and higher abundances of Zr (0.06%) and Nb (upto 0.1 %).
Petrochemical Basis for the Rank (Maturity) Evaluation of Permian Coals of the Ramagundam Coal Belt, Godavari Valley Coalfield, Andhra Pradesh
Authors: Singh Ganesh P.
Published: November 2024

The Permian coals of Ramagundam coalfield are sub-bituminous to high volatile bituminous in rank on the basis of chemical (carbon, and volatile matter) and petrographic (reflectance-Rom,) parameters. These coals are characterized as kerogen type-III. Reflectance (Rom) values suggest the maturation temperatures rapging from 46° and 108°C and depth of burial, of coal bearing horizons varies from 1725 to 2175 metres.
Pan-African U-Pb Zircon age from Apatite-Magnetite Veins of Eastern Ghats Granulite Belt, India
Authors: Kovach V. P. , Salnikova E. B. , Kotov A. B. , Yakovlevn S. Z. , Rao A. T.
Published: November 2024

206Pb/238U ages of zircon correspond to 502 ± 3 Ma and 207Pb/206Pb ages are equal to 508 ± 14 Ma. U-Ph isotopic study of the Kasipatnam zircon has led to the recognition of pan-African thermal event in the Eastern Ghats Granulite Belt, India.
Eocene Rodents From New Localities in Himachal Pradesh, Northwest Himalaya, India: Biochronologic Implications
Authors: Kumar Kishor , Loyal R. S. , Srivastava Rahul
Published: November 2024

The report of Eocene rodents from Himachal Pradesh is of considerable biochronologic and biogeographic significance. It corroborates that the Eocene rodent-yielding horizons at the top of the Subathu formation in Jammu and Kashmir and Himachal Pradesh (India) and of the Kuldana Formation in Pakistan are in the same time frame. It also extends the geographic range of the Eocene chapattimyid rodents to about 300 km east of earlier known localities in Rajauri and Reasi districts, Jammu and Kashmir.
Classification and Estimation of Ore-Reserves
Authors: Curtis L. C.
Published: November 2024

Four main (national) codes or guidelines cover classification and estimation of reserves of all minerals and types of deposits without specific definition. A simplified classification system is suggested together with specific development and sampling requirements for reserves of gold ore in shear zones in Archaean rocks.
Whole Rock and Mineral Chemistry of Aluminous Granulites From the Eastern Ghats Granulite Belt, Andhra Pradesh
Authors: Rao A. T. , Divakara Rao V. , Yoshida M. , Arima M.
Published: November 2024

The whole rock analyses confirm the basic to intermediate nature of the protolith (SiO2, > 53% - < 67%) with high alumina (highest 22.18%) and high K2O (~ 4%). Metamorphic segregation as well as source rock compositions appear to have contributed -to the formation of high alumina granulites. The temperatures of metamorphism estimated using garnet - hypersthene/cordierite pairs range from 680-980°C, The gamet-cordierite reference temperatures with narrow range 700-750°C, indicate a pressure range of 5-7 kbar for the garnet-orthopyroxene-plagioclase-quartz assemblage in the aluminous granulites. Textural relationships of cordierite breakdown and reappearance of cordierite supplement the two generations of cordierite from aluminous granulites in the Eastern Ghats Granulites Belt.
Rare Earth Element Geochemistry of Selected Mafic-Ultramafic Units from Singhbhum Craton: Implications to Source Heterogeneity
Authors: Roy A. , Sarkar A. , Bhattacharya S. K. , Ozaki H. , Ebihara M.
Published: November 2024

Modelling ofREE data indicates that while mafic rocks of Dhanjori Group are partial melting products of a spinel Iherzolite source, Dalma ultrabasics are the residue after the melt-extraction from an original garnet lherzolite rock. Ultramafics of Newer dolerite dykes indicate either derivation by mantle meta somatism or effect of post magmatic serpentinisation. REE data in conjunction with the available geochronological data suggest that significant mantle heterogeneity existed over relatively smaller distances (~100 km) even during Proterozoic and that the mantle evolved in a non-uniform manner with distinct localised processes.
The Intensely Bored Rocks in Vinjhan (Kutch) Indicate Glossifungites Ichnofacies
Authors: Patel S. J. , Shringarpure D. M.
Published: November 2024

The occurrence of Glossifungites ichnofacies from the Vinjhanian stage exposed near Vinjhan in Kutch have confirmed its development of the firm but unlithified substrates possibly intertidal to subtidal in nature where the semi consolidated substrate provided resistance to erosion and supported three generations of borings by different organisms. The filling of the borings with gypsum and development of iron-oxide stains on them indicate a major regressive phase of the Vinjhanian stage and diagenetic effects due to chemical variations in the depositional system.
Sedimentological Study of Kwada and Belekeri Bay Beaches, Uttara Kannada, West Coast, India
Authors: Hanamgond P. T. , Chavadi V. C.
Published: November 2024

Granulometric studies of 317 sediment samples collected at different micro-environments were used to understand the depositional environment and their spatial (cross-shore and longshore) and temporal (seasonal) grain size variations. The study involves EOF analysis to understand the size distributions at each of the micro-environments through different seasons. With the help of the available textural tools sediment movement and high energy areas have been distinguished.
Electrofacies Analysis and Paleogeographic Maps of Sands within the Lower Clay Marker of Lakhmani Field
Authors: Rao A. B. N.
Published: November 2024

An integrated study of three sands within Lower Clay Marker formation (LCM) of Lakhmani field, Assam has been carried out to identify the geometry of the hydrocarbon-bearing sand. Based on the sand geometry the facies changes in petrophysical properties of the rock areally could be explained. Depositional environments in heavily drilled areas can be interpreted with confidence and the same ideas can be imparted to sparsely drilled areas for improving the evaluation in relatively unexplored areas.
Distribution and Succession of Jurassic Rocks in Gora Dodgar, Pachchham "Island", Kachchh, India
Authors: Pandey Dhirendra Kumar , Fuersich Franz T.
Published: November 2024

Its prolific fossil fauna and well exposed sedimentary sequence make Kachchh, a Mesozoic pericratonic basin at the western margin of the Indian plate. one of the classic areas of Jurassic geology. The Jurassic sediments represent, for their most part, shallow, largely nearshore shelf environments characterized by a moderately rich bivalve-dominated fauna. An exception is the Eomiodon Red Sandstone Member, which is characterized by brackish biota and contains interludes of non-marine coastal plain sedimentation.
Gravity Bases Established by Cochin University of Science and Technology (CUSAT) over Parts of Northern Kerala
Authors: Radha Krishna M. , John Kurian P. , Nambiar C. G. , Krishna Mohan S.
Published: November 2024

A network of 30 gravity base stations have been established. The dynamic drift curves show an average drift rate of less than 0.006 mgal/min. The observed gravity values have repeatability of 0.08 mgal, and can be used for regional gravity surveys.
Oxygen Isotopic Studies of Ice, Snow and Water Samples near the Indian Stations in Antarctica
Authors: Bhattacharya S. K. , Nijampurkar V. N.
Published: November 2024

Oxygen isotopic ratios in water samples collected from various sources (recent snow, glacier ice, coastal sea, lakes etc.) near the two Indian stations in Antarctica (Dakshin Gangotri and Maitri) have been measured. The general range of d18O values is from -14 to -30 (in ‰ w.r.t SMOW). The fresh water lakes in the Schirmacher Range area receive 30 to 40% of their input from melt water of adjoining glacier. This glacier has old ice characterized by extremely depleted d18O value of -42‰ at the shallow depth of 10 m. This is not normally expected and can complicate interpretation of d18O profile in cores from this region for palaeoclimatic studies.
Rainwater Harvesting - A Possible Seasonal Addition to Bangalore Water Supply
Authors: Curtis L. C.
Published: November 2024

The conservation by storage in underground cisterms of a significant proportion of local rainfall, to provide a supplementary supply during the non-monsoon months, is a feasible proposition. Basic requirements in respect of cistern capacities, possible supply levels, excavations required, possible layout and preliminary cost estimates are indicated.
Estimation of Hydraulic Characteristics of Alluvial Aquifers from Electrical Resistivity Data
Authors: Singhal D. C. , Niwas Sri , Shakeel M. , Adam E. M.
Published: November 2024

The applicability of geophysical techniques has been examined for evaluating aquifer properties like transmissivity and hydraulic conductivity of alluvial anisotropic aquifers of Saharanpur area, Western Uttar Pradesh. The available pumping test data for various tube well sites is reinterpreted by using different methods for obtaining the aquifer characteristics. The available vertical electrical soundings (VES) data in the vicinity of the sites of pumping tests have been interpreted and true resistivity and thickness determined for each site under both isotropic and anisotropic conditions. Three types of empirical relations from the data are established for estimating the hydraulic parameters from electrical data: (i) Relation between hydraulic conductivity and apparent formation factor; (ii) Relation between hydraulic conductivity and a modified aquifer resistivity; (iii) Relation between transmissivity and modified transverse resistance.

It is concluded that in an alluvial area where Darcy flow is deemed to be valid, hydraulic conductivity and transmissivity of aquifers can be estimated with reasonable accuracy at aquifer level by using relations between hydraulic properties and resistivity parameters.
Geothermobarometry and Fluid Inclusion Studies of Leucogneisses from Schirmacher Region, East Antarctica
Authors: Rameshwar Rao D. , Sharma Rajesh , Gururajan N. S.
Published: November 2024

The granulite-gneiss terrain of Schirmacher region, East Antarctica includes mafic to acid granulites pervasively intruded by stringers, bands, lenses and stocks of felsic rocks. The late stage felsic rocks are the leucocratic rocks and are the focus of this paper. They have concordant to discordant relation with the associated felsic and other granulitic rocks of the region.

The fluid inclusions, show three stages of f1uid entrapment. The monophase CO2 inclusions, with densities in the range of 0.996 to 0.811 g/cm3, show pressures of about 5.1 ± 0.6 kbars at inferred temperatures of 675 ± 25°C and indicate peak metamorphism after crystallization. Early stage deformed aqueous inclusions, however, represent initial crystallization. Entrapment of these inclusions was followed by carbonic aqueous inclusions, whose CO2 densities range from 0.816 to 0.624 g/cm3 with increasing H2O fluid entrapment occurring during the retrogressive stages. The increased concentration of aqueous fluids has resulted in biphase aqueous inclusions in trails. Their density and homogenization temperatures indicate a pressure of 2 ± 0.5 kbars.

The P-T trend observed from fluid inclusion studies is ref1ected from mineral equilibria studies. The GMBPQ assemblage of these rocks gave temperatures and pressures of 675 ± 25°C and 5.5 ± 0.3 kbars respectively. Further, the two-feldspar thermometry for these rocks record a reequilibrated temperatures of 444 ± 9°C. These P-T conditions of the leucogneisses suggest around 18 km of crust to have been removed, indicating > 50 km thick crust during the amphibolite facies metamorphism corresponding to geothermal gradients of around 37°C/km. A successive decrease in estimated P-T conditions along with density and compositional information suggests retrogression and compressional cooling path for these rocks.
Organic Carbon and Total Phosphorus in the Sediments of Some Selected Mangrove Ecosystems of Kerala, Southwest Coast of India
Authors: Badarudeen A. , Padmalal D. , Sajan K.
Published: November 2024

Distributions of organic carbon (OC) and total phosphorus (P) in the sediments of three mangrove ecosystems located at Veli, Kochi and Kannur areas, southwest coast of India are described. The mangrove sediments of Kannur contain comparatively high concentration of DC (4%) than that of Veli (2.6%) and Kochi (3.7%). Total P records the highest concentrations in Kochi (av. 0.395%) compared to Veli (0.055%) and Kannur (av. 0.323%) mangroves. However, their distribution does not yield any specific pattern with respect to landward, intermediate and shallow water profiles. Statistical analysis of OC and P contents against the various causative factors stresses the role of particle size in regulating their distributional pattern in mangrove environments.
Late Quaternary Environment, Palaeontology and Culture of Tarafeni Valley, Midnapur District, West Bengal - A Preliminary Study
Authors: Basak Bishnupriya , Badam G. L. , Kshirsagar Anupama , Rajaguru S. N.
Published: November 2024

The authors present an integrated data on the Quaternary studies carried out during the 1993-95 field seasons in a lesser known area, the Tarafeni Valley in Midnapur District, West Bengal. Microliths primarily made on chert, quartzite have been found in association with colluvial deposits formed more or less contemporaneously with underlying nodular calcrete of pedogenic Oligin. Occurrence of several vertebrate fossils on the surface of the calcrete at Dhuliapur indicates Late Pleistocene age of the artefact bearing colluvial deposits. The formation of pedogenic calcrete in a sub-humid environment, with an average annual rainfall of 1600 - 2000 mm, suggests the presence of semi-aridity in Late Terminal Pleistocene period.
Trace Fossils from the Cambrian Sequence of Zanskar (Ladakh Himalaya)
Authors: Shah S. K. , Kumar Ashok , Sudan C. S.
Published: November 2024

Spiti - Zanskar Basin of Himalaya exposes rocks ranging in age from Proterozoic to Early Cenozoic. Cambrian trilobites, brachiopods and trace fossils are known from the Kurgiakh area of the basin. The present paper concerns with Early Cambrian trace fossils reported from the same stratigraphic section in which trilobite body fossils are known. The assemblage of trace fossils include: Chondrites sp., Cruziana sp., Rusophycus sp., Phycodes palmatum, sp., Didymaulichnus sp., Protichnites sp., Monomorphicnus monolinearis, Diplichnites sp. associated with scratch marks indicating trilobite movements. The finding of trace fossils far below the definite brachiopod and trilobite body fossil horizons in the Lower Cambrian sequence of Kurgiakh area of Zanskar is of significance.
Depositional Environment of Cuddalore Sandstone Formation, Tamil Nadu
Authors: Selvaraj K. , Ramasamy S.
Published: November 2024

Cuddalore Sandstone (Mio-Pliocene) of Neyveli and Ariyalur areas has been studied to infer the depositional environment. Granulometrically, poorly to moderately sorted and fine to very finely skewed sandstones are petrographically identified as feldsarenite and litharenite. Source area for the Neyveli sediments included pyroxenite, amphibolite and granodiorite and the Ariyalur sediments were probably, derived from granite and monzonite. Major elemental data show the eugeosynclinal tectonic setting for Neyveli and taphrogeosynclinal setting for Ariyalur area. The overall study suggests a deltaic environment.
Ignimbrite Deposits from North of Mumbai in Western Part of Deccan Flood Basalt Province, India
Authors: Sharma R. K. , Pandit M. K.
Published: November 2024

The Sasunavghar-Juchundra area in the western part of Deccan Flood Basalt Province exposes repetitive acidic pyroclastic sequences overlying intermediate to basic pyroclastic basal flows. These acidic tuffs conform to typical 'ignimbrite' eruptive and depositional environment. The explosive activity has probably resulted from a localised collapse of eruptive column.
Textural Characteristics and Mineralogy of the Suspended Sediments of the Cauvery River Basin, India
Authors: Ramanathan A. L. , Subramanian V.
Published: November 2024

The sediment mean size varies from 4.7-8.3 phi (medium-fine silt), moderate to poor sorting, near symmetrical to strongly fine skewed and platy to very platykurtic. Local bank erosion, redistribution and tributaries control the grain size distribution in the basin. Chlorite and montmorillionite are the dominant clay minerals followed by kaolinite and illite.
A Glance Through the Seismicity of Peninsular India
Authors: Bansal Brijesh K. , Gupta Sushil
Published: November 2024

This paper reports the status of seismicity of the Peninsular Indian region based on historical earthquake data from 1200 to 1995 AD. A list of earthquakes occurring within the geographical area between latitude 8° N-24° N and longitude 70° E-86° E has been compiled. The current seismic activity in Peninsular region shows evidence of neotectonic movements. Based on the knowledge of the geotectonics of the area and the epicentral distribution of earthquakes, seismogenic zones in the region have been demarcated. Among the 11 such zones Western Ghat. Narmada~Son and °Rann of Kutch are relatively more active.
Felsic Volcanics Interlayered With Sediments of the Marwar Supergroup at Chhoti Khatu, District Nagaur, Rajasthan
Authors: Paliwal B. S.
Published: November 2024

A thick pile of un deformed and unmetamorphosed sediments exposed to the west of the Aravalli mountain range in Rajasthan. earlier known as the Trans-Aravalli Vindhyans and later renamed as the Marwar Supergroup, are considered to rest unconformably over the Malani Igneous Suite of rocks. Felsic volcanics have been observed around Chhoti Khatu. in Nagaur district for the first time interlayered with sediments of the Marwar Supergroup. They occur sandwiched between the underlying Sonia Formation and the overlying Girbhakar Formation of the Jodhpur Group (the Marwar Supergroup). This interesting relationship may help in deciding the age of the Marwar Supergroup.
Quantitative Assessment of Seismic Hazard in Eastern-Northeastern India Through Poisson Probability Density Function Analysis
Authors: Dasgupta Sujit , Bhattacharya Auditeya , Jana Tapan K.
Published: November 2024

Temporal occurrence of earthquakes of magnitude = 5.5 and 6.0 was statistically analysed for the entire eastern-northeastern India which is seismically active. High seismicity in the region is related to plate margin activity in the Himalaya and Burmese arc. Non-stationary Poisson distribution provides a good fit to analyse earthquake sequence for the entire area of eastern-northeastern India and two subareas within it, viz., the Himalaya and the Burmese arc. For the entire area there is a 90% probability for the occurrence of at least one earthquake of magnitude (Mb0)= 6.0 in any time window of 5 years, while the probability is 98% for an event of Mb0 5.5 in any two years time slot. Similarly for the Himalayan tectonic domain, the probability is 70% and for the Burmese arc it is 90% for at least one earthquake of Mb= 6.0 within a recurrence period of ten years. As earthquakes in the region above the threshold magnitudes of 5.5 and 6.0 follow a poisson distribution, probability density function maps for both the threshold magnitude were prepared for 1°x1° blocks with rate of occurrence(?) for each 0.5° overlapping grid. These maps are used to calculate p~rcent probabilities with different return periods. Seismic hazard maps with percent probabilities for the occurrence of at least one earthquake with return periods of 20 and 50 years are presented for Mb0=6.0 and with return periods of 5 and 10 years for Mb0=5.5.
Rare Earth Element Geochemistry of Modern Detrital Sediments from Chaliyar River, Northern Kerala
Authors: Hariharan G. N. , Nambiar C. G.
Published: November 2024

?REE in the detrital sediments from Chaliyar river channel ranges from 37.7 to 65.5 ppm, which is around 0.3 times that of the average crust and NASC, and is lower compared to that of their provenance rocks. The highly fractionated chondrite-normalized REE pattern of the average sediment mimics that of the average provenance rock. but for the presence of a negative europium anomaly that is suggestive of preferential removal of plagioclase during weathering. The similarity in the REE contents of samples from different locations in the main channel reflects the immobility of rare earths in fluvial transportation and tectonic stability of the basin
Effect of Urbanisation on Groundwater Regime, Dhaka City, Bangladesh
Authors: Ahmed K. M. , Hasan M. A. , Sharif S. U. , Hossain K. S.
Published: November 2024

Groundwater abstraction in Dhaka city has increased more than 700% during the last three decades. Consequently, water level has dropped to 20 m below sea level in the south central part of the city, where the ground surface elevation is 5.7 m. The rate of water level decline varies from 0.75 to 1.5m/year at different observation points within the city.

Iso-conductivity map of the groundwater depicts higher electrolytic conductivity (EC) value (500 to 800 μ1S/cm) in the southern part of the city, particularly along the river Buriganga. compared to the northern part (l00-2oo μ1S/cm). Contamination in the aquifer of southern part is attributed to recharge by polluted water from the Buriganga. Monitoring results of deep tube wells (DTWs) and hand tube wells (HTWs), located in municipal waste and industrial effluent disposal sites, show a marked depth variation in groundwater EC. Higher EC values in the HTWs demonstrates contamination in upper part of the aquifer from the disposal sites. Major ions and trace element concentrations of the water samples also reveal similar pattern. Increasing trend in the ionic concentrations. particularly cl- and N03 , as observed in the historical record indicates gradual quality deterioration.
Magnetic Properties of Banded Magnetite Quartzites of South India
Authors: Subba Reddy N. , Darga Reddy N. , Prasad C. V. R. K.
Published: November 2024

Two hundred and ninety samples of Banded Magnetite Quartzites from Archaean granulitegneiss terrain and greenstone belts of Southern India are investigated for magnetic granillometry. It is suggested that these mainly contain MD grains with a combination of SD or CD grains. The granulometry and other magnetic properties of samples from the two regions are similar.
Estimation of Parameters of Crystalline Rock Aquifers: A Case Study
Authors: Singh V. S. , Thangarajan M.
Published: November 2024

Aquifer parameters viz. transmissivity (T) and storage coefficient (S) are a pre-requisite for the assessment of groundwater resources in an area. A large number of dugwells tapping the top phreatic aquifer (comprising mostly weathered material) are being utilized for irrigation and/or domestic purposes. Use of such wells makes the estimation of aquifer parameters easy and cost effective. A case study in Vaippar river basin, a hard rock region in Tamil Nadu (India) is presented.
Wall Rock Alteration in Cu-Zn-Au Bearing Volcanogenic Massive Sulphide Deposit at Danva, District Sirohi, Rajasthan
Authors: Kirmani I. R. , Fareeduddin
Published: November 2024

The Upper Proterozoic mafic volcanic suite of the Delhi Supergroup between Nanna and Deri sectors of Rajasthan host several volcanogenic massive sulphide prospects. The massive sulphide ore body at Danva is enveloped by hydrothermally altered volcanic rocks containing sulphide-bearing stock work mineralization. Geochemistry of the unaltered metavolcanics indicate that they are basalts with calc-alkaline affinity. The main types of hydrothermillly altered rocks are quartz-biotite schist, quartz-biotite-sericite schist and quartz-sericite schist.

Mass balance studies indicate marginal and significant gains of SiO2, H2O and K2O during the processes of biotitization and sericitization. Na and Ca show strong depletion. The iron oxides, in general, record marginal to heavy depletion whereas sulphur is significantly added during the hydrothermal activity. It is suggested that Au has largely been mobilized during sulphidation process.
Fossil Till Ball and Armoured Mud Ball from the Glaciofluvial Talchir Formation, Talchir Gondwana Basin, Orissa
Authors: Sen D. P. , Sit Suman Krishna
Published: November 2024

Armoured mud balls and till ball (sand ball) are reported for the first time from the Permocarboniferous Talchir Formation. The balls occur within a gullied part of the boulder bed. The balls found in the environment result from block breakage due to undercutting of a till face by meltwater stream and rolling during transportation. The unannoured spherical balls of diameter 3-14 cm composed of coarse materials are formed around tillite blocks and flat pebbles. whereas balls formed around clay or mud lumps are later armoured by grannule and pebble size clasts. The balls are termed till balls and mud balls respectively. Since the balls composed of coarse materials may also be derived from the environments other than glacial environments, it is appropriate to term these balls as sand ball.

Sand balls and mud balls along with associated primary structures may be used as palaeogeographic indicators. Presence of these balls and associated structures also reveal that though apparently the Boulder bed appear to be a single lithostratigraphic unit, in reality it is a complex of number of gravity flow deposits.
Orgin and Palaeoenvironmental Aspects of Red Sediments from Bavanapadu-Ichchapuram, Andhra Pradesh
Authors: Gaitan Vaz G. , Mohapatra G. P. , Hariprasad M.
Published: November 2024

Red sediments occur as three shore linear patches between Bavanapadi and Ichchapuram in north Andhra Pradesh coast. The unstructured red sediment lying over an antecedent topography is divisible into lower unit with calcretes and upper unit devoid of calcretes. The field observations, grain size parameters, heavy mineral assemblage and SEM studies of quartz grains signify an aeolian source, possibly formed by sand transport from the exposed continental shelf during the Quaternary regressive cycles. Formation of calcrete and red pigments are considered as post depositional phenomena. SEM studies of ilmenite, XRD and chemical studies of finer fractions reveal the in situ derivation of red haematite and goethite pigments from the alteration of ilmenite and precipitated interstitially to give rise to red colour.
Development of Oxfordian (Early Upper Jurassic) in the Most Proximally Exposed Part of the Kachchh Basin at Wagad Outside the Kachchh Mainland
Authors: Krishna Jai , Pathak Deo B. , Pandey Bindhyachal
Published: November 2024

Over a century and half the Kachchh Oxfordian ammonoid record has remained restricted to Early and early Middle Oxfordian, that too in extremely condensed/reworked/starved sedimentary facies. In this backdrop we here discuss the Middle and Late Oxfordian ammonoid faunas recently discovered in Wagad (Krishna et al. 1994a, b). Among these the mid Middle Oxfordian stratigraphic interval is found exceptionally rich in ammonoids at Kantkote - the richest ever discovered in the Kachchh basin. It is made up of a 10m thick succession of 13 ammonoid levels. Farther up after a thick ammonoiddevoid sediment interval appear again a few rather ammonoid scarce levels of late Late Oxfordian age with doubtful extension into early Early Kimmeridgian. The Oxfordian/Kimmeridgian boundary may be included in the latter of the two ammonoid bearing intervals in the Orthosphinctes/Lithacosphincteslevels. The rich mid Middle Oxfordian anunonite fauna inspite of being known for over a century from loose imprecise, unlocalised collections has been stratigraphically precise and dated for the first time in the relatively unexplored. stratigraphic section of Wagad.

The anunonoid abundant mid Middle Oxfordian Transversarium Zone succession in addition of the restricted Indo-East African mayaitins and widely distributed perisphinctins includes a few examples of the Mediterranean Gregoryceras gr. fouquei, Euaspidoceras and Taramelliceras and suggests maximum flooding and eustatic rise in the Kachchh Mesozoic in the Middle Oxfordian Schilli Subzone of the Transversarium Zone. Another significant aspect of this fauna is the marked continuous presence of the compressed platyconic densely costate lithacoceratins (Larcheria and Discosphinctes) stocks in parallel with the true perisphinctin and mayaitin lineages almost althrough the Middle Oxfordian (Krishna et al. 1994a. b, 1995, 1996a). The mayaitins are for the first time precisely ranged up to the Transversarium Zone.

The basin margin Oxfordian ammonoid succession at Wagad shows recurrence only of small portion in its basal part of the previously known Oxfordian section of the Kachchh Mainland (e.g. the common Perisphinctes-Epimayaites assemblage of bed G Lakbapur). The remainder ca 200 m thick Oxfordian at Wagad is interpreted here to correspond to the non-depositional submarine stratigraphic gap elsewhere in the relatively deeper parts of the basin from the later part of the Middle Oxfordian Plicatilis Zone to the early Early Kimmeridgian Hypselocyclum Zone.
Randon/Helium Survey of Thermal Springs of Parbati, Beas and Sutlej Valleys in Himachal Himalaya
Authors: Virk H. S. , Sharma Anand K. , Kumar Naresh
Published: November 2024

India has more than 300 thermal springs spread over the entire geographical area of the sub-continent Some of these springs have linkage with Indian mythology and are famous pilgrimage centres since historical times. The temperature of water recorded in these springs varies from 40°C to that of steam. Some of them are being exploited as a source for geothermal energy.

The purpose of this study is to measure radon and helium activity in the thermal springs of Himachal Himalaya. Radon is estimated in the soil and thermal waters using alpha spectrometry and scintil1ometry, respectively. The radon activity is maximum (716.3 Bq/L) in thermal spring (3) at Kasol and minimum (15.9 Bq/L) in a natural spring (bauli) at Takrer Radon concentration is highly variable in the Parbati valley with minimum value of 2230±430 Bq/m3 recorded at Chhinjra on the banks of river Parbati and a maximum value of 57700±2050 Bq/m3 at Dharmaur, the site of uranium ore exploitation by the AMD(DAE). Helium is estimated in the thennal springs by using a Helium Leak Detector (sniffing technique). The radon and helium contents of Kasol thermal springs are correJatable with high radioactivity in the soil of the area as revealed by Alpha Guard survey in the environs of Parbati valley. The helium content recorded in thermal springs is found to vary between 15-90 ppm.

Radon and Helium are well established as geochemical precursors for earthquake prediction studies. Helium/Radon ratio seems to be a better predictive tool for earthquakes in comparison to individual radon and helium precursors.
A New Geochemical Reference Sample of Granite (DG-H) from Dalhousie, Himachal Himalaya
Authors: Saini N. K. , Mukherjee P. K. , Rathi M. S. , Khanna P. P. , Purohit K. K.
Published: November 2024

A new geochemical reference sample of Granite named as DG-H from Dalhousie, Himachal Pradesh is proposed for collaborative study. The sample has been tested for its suitability as a reference standard in terms of its bulk homogeneity using F-test carried out for 16 fractions of the sample analysed in duplicate. The relevant information like, location, geological set-up, mineralogical make-up, petrography, expected chemical composition and F-ratios derived for major oxides are given for the benefit of potential contributors and users. The proposed standard may prove useful for analysis of granitic rocks with high Cr and lower abundances of elements like Ba, Ca, Cu, Nb, Ni, Sr, Th, Y and Zr.
A Note on Gold Mineralisation in Banded Iron Formation, Goindari - Pararawa, Sonbhadra District, Uttar Pradesh
Authors: Khan M. A. , Dwivedi G. N.
Published: November 2024

Preliminary sampling of banded iron formation (BIF) of Agori Formation in Goindari and Pararawa areas of Sonbhadra district, has indicated gold mineralisation. Samples of BIF analysed 0.2g/t to 0.96 g/t and a sheared quartz vein sample gave 5.46 g/t gold.
Basin Configuration in Konkan Deepwaters: Western Indian Offshore
Authors: Thakur Sanjeev S. , Arasu R. T. , Subhramanyam V . S. R. , Srivastava A. K. , Murthy A .V. S.
Published: November 2024

The sedimentary patch in Konkan deepwaters, located west of the Konkan continental shelf contains over 3 km thick sediments. Based upon the interpretation of over 11,000 line km of seismic data, gross basin configuration model has been worked out. The basin floor at the base of Tertiary is differentiated into a series of rift zones containing synrift sediments. These zones are superimposed by post-rift sediments deposited as a result of flexurally distributed thermal subsidence. Therefore, the sediments in the basin are divisible into three distinct mega-seismic packages denoting three major tectonic habitats of the evolution of the Konkan continental margin. Based upon the basinal configuration of each mega-seismic package in space and time, tectono-sedimentary evolution of the continental margin is brought out with an assessment of hydrocarbon prospects.
Late Quaternary Microinvertebrate Assemblage from Fluvio-Lacustrine Sediments of the Lamayuru Basin, Ladakh Himalaya
Authors: Mathur P. D. , Kotlia B. S.
Published: November 2024

The paper reports molluscs (bivalves and gastropods) and ostracods from the Late Quaternary fluvio-lacustrine sediments of the Lamayuru basin, as well as from a present day lake in Leh, Ladakh. Eight fossiliferous horizons were located within the sequence. Out of seven micro-invertebrate taxa recovered. five (Pisidium sp. indet, Pisidium mitchelli, Succinea sp. indet, Gyraulus convexisculus and llyocypris gibba) are reported for the first time from the Ladakh region.
Deposition, Degradation and Preservation of Organic Carbon in the Pulicat Lake, Tamil Nadu, East Coast of India: Preliminary Results
Authors: Periakali P. , Eswaramoorthi S. , Subramanian S.
Published: November 2024

The sequential extraction of core sediment samples of Pulicat lake for the determination of exchangeable, carbonate-bound. Fe-Mn oxides-bound, and organic-bound fractions of Fe and Mn were carried out to study the remineralization of organic matter in the sediments. Iron and manganese oxides are highly depleted in the upper portion (0-18 cm) of the core due to their reduction during organic matter oxidation. The model calculations based on the solid phase organic carbon depth profile indicate an average accumulation rate for organic carbon in the Pulicat lake sediments to be 13.5 gC/m2.yr. The average remineralization rate is 12gC/m2.yr. This is around 89% of the organic carbon deposited in thc sediments. The remineralization of organic carbon in this lake sediment could release 16 x 103 tonnes of CO2 /yr.
Palaeocurrents and Depositional Setting in the Banganapalle Formation, Kurnool Sub-Basin, Cuddapah Basin, Andhra Pradesh
Authors: Lakshminarayana G. , Bhattacharjee S. , Kumar Ajit
Published: November 2024

Palaeocurrents of the diamondiferous Banganapalle Formation show convergence towards Nandyal depression in the Kurnool Sub-basin. Localised depocentres, separated by E-W trending ridges, are identified near Kurnool, Paniam, Uppalapadu and Proddatur. These ridges pass through Gani, Banganapalle and Gandikota and have influenced sediment dispersal pattern in the Banganapalle Formation. Provenance for the Banganapalle Formation was mainly the intrabasinal tract occupied by lower Cuddapah sediments, igneous intrusives and the basement located to the west. Deposition commenced in an alluvial environment followed by intertidal setting.
Evaluation of Hydrouranium Anomalies in the Crystallines Along the Southwestern Margin of Cuddapah Basin, Andhra Pradesh, India
Authors: Kumar Sunil , Dash S. K. , Sharma U. P. , Ramadoss K. , Singh Rajendra , Dwivedy K. K.
Published: November 2024

Univariate and multivariate statistical analyses, especially correlation study and factor analysis of uranium and other major ions in the groundwater of Chenchalapalle-Mulapalle area, known for its fracture controlled uranium mineralization, in the southwestern crystalline margin of Middle-Upper Proterozoic Cuddapah basin have revealed - (i) several well defined and distinct anomaly zones of > 200, > 500, > 1000 ppb of uranium, (ii) enriching factors like TDS(Ec), HCO3-, Na+, K+, Ca+2 , Mg+2, Cl-, SO4-2 have poor to negligible influence on high uranium content and (iii) factor-3, identified as "mineralization factor" has high loading for uranium (0.948). The study on saturation indices of several uranium and other minerals indicated undersaturation for most of the aqueous uranium species, except for a few hydroxides. Particularly, schoepite (2UO3.5H2O) has low to moderate degree of supersaturation in samples from major anomalous zones.

Based on the distinctive hydrogeochemical attributes and geological and structural favourability factors, the tracts in the vicinity of Varikuntapalle (VKP). Dapepalle (DPL) and Pulikunta (PLK) villages, between Chenchalapalle-Mulapalle area in the southwestern crystalline margin of Cuddapah basin, are designated as potential target areas for detailed exploration.
Palaeomonsoon History During the Late Quaternary: Results of a Pilot Study on Sediments from the Laccadive Trough, Southeastern Arabian Sea
Authors: Sathy Naidu A. , Shankar R.
Published: November 2024

Stratigraphic sections of carbonate-free sediments at 5-10 cm intervals of a 1.2 m core (CA 3800) from the Laccadive Trough (water depth: 1724m) were analyzed for organic carbon (OC), nitrogen (N), OC/N, d13C and d15N, using a continuous flow stabte isotope mass spectrometer. Data on CaCO3 were also used. The generally high concentrations of OC (0.9-2.16%) and CaCO3 (32.2-54.4%) presumably reflect high productivity at the core site. The predominantly marine origin of the OC is indicated by the -19.6 to -18.2 d13C values.

Significantly higher carbonate is recorded in the Holocene than in the late Glacial, presumably reflecting increased Holocene productivity resulting from enhanced upwelling and summer monsoon during the Interglacial than Glacial. The late Glacial to Holocene increase in the mean OC/N from about 13 to 16 and d15N by 2‰, presumably mirrors a relative increase in denitrification in the oxygen-deficient zone coinciding with enhanced Holocene productivity in the southeastern Arabian Sea. Our interpretation on the paleoproductivity is consistent with those for the western Arabian Sea proposed by earlier workers for the above time period.