bluuebunny/crossref_metadata_2025 huggingface dataset:
Secular Trends in Rare Earth Element Patterns of Precambrian Iron-Formations from India and Greenland
Authors: Appel Peter W. Uitterdijk , Mahabaleswar B.
Published: November 2024

Rare earth element (REE) analysis have been carried out by neutron activation on samples of iron-formation from southern India and from West Greenland. The investigated iron-formations range in age from about 1800 m. y. to more than 3000 m. y. The different iron-formations have undergone very diffeferent metamorphic histories, from the virtually unmetamorphosed iron-formation in West Greenland, through amphibolite to granulite facies metamorphism in southern India.

The results clearly demonstrate that europium anomalies cannot be used as indicators for oxygen contents of the Precambrian atmosphere. A secular trend has been established in the Precambrian iron-formations, whereby the oldest iron-formations display only slight fractionation of light REE relative to heavy REE, and this fractionas tion increases with decreasing age of the iron-formations.
The Jutogh Group of Metasediments of the Himachal Himalaya: Its Lithostratigraphy
Authors: Srikantia S. V. , Bhargava O. N.
Published: November 2024

The Jutogh Group of the Himachal Himalaya is divisible into eleven formations based on normal order of superposition, lithological association, lateral persistence and systematic mapping. This study helps greatly in reconstructing the sedimentary history, structural evolution and promoting better inter-regional correlation.
Mineralogical Characterisation of the Complex Sulphide Ores from Askot, Pithoragarh District, U.P
Authors: Acharya B. C.
Published: November 2024

Sphalerite, galena, chalcopyrite and arsenopyrite are the dominant ore minerals with minor amounts of pyrrhotite, cubanite, marcasite, pyrite and chalcocite. Bornite, stibnite, native bismuth and silver are present in trace quantities. Chemical analyses of the samples reveal variations in different metal values. Sphalerite, galena, chalcopyrite and arsenopyrite are analysed by Scanning Electron Microscope coupled with EDAX analyser to decipher the distribution of valuable elements in them.

The ore needs grinding to 45 microns to liberate 91.70% of galena, 94.49% of sphalerite, 95.31% of chalcopyrite and 98.45% of composite galena-chalcopyrite-sphalerite. This suggests that by physical beneficiation, individual concentrates of Pb, Cu and Zn with good recoveries may be difficult to obtain, but a bulk concentrate of these three metals can be produced.
Geology and Geochemistry of Spinifex-Textured Peridotitic Komatiite from Mayasandra Schist Belt, Karnataka
Authors: Charan S. N. , Naqvi S. M. , Ramesh S. L.
Published: November 2024

Spinifex-textured peridotitic komatiite occurs on the southeastern margin of Mayasandra schist belt near Nagamangala in Karnataka. Preservation of spinifex-texture made up of pseudomorphically altered phenocrysts of olivine and less commonly clinopyroxene set in a groundrnass of skeletal augite and devitrified glass in the komatiite, is essentially perfect in spite of alteration, deformation and metamorphism. Petrography shows dissimilar shapes and dimensions of the crystals, with more than one pattern of crystal arrangement in the texturally layered komatiite, clearly indicating that conditions and rates of crystallization were not uniform throughout the cooling unit. Compositional variations in terms of major and trace elements appear to be broadly consistent with fractionation of olivine followed by clinopyroxene. The high contents of MgO, Ni, Cr and extremely low percentages of TiO2, Na2O, K2O in the spinifex-textured ultramafic komatHte compare favourably with similar rock types reported from Canada, S. Africa and Australia.
On the Evolution of the Godavari Gondwana Graben, based on LANDSAT Imagery Interpretation
Authors: Ramanamurthy B. V. , Parthasarathy E. V. R.
Published: November 2024

Lineaments numbering about 110, show two major preferred directions, i.e., northwest-southeast and northeast-southwest. Majority of the lineaments are believed to be of Archaean ancestry. The Precambrian Pakhal, Sullavai, and the upper Palaeozoic to Mesozoic Gondwana sediments were deposited largely in a fault-controlled, successively developed troughs, broadly trending in a northwest-southeast direction. A five-stage tectonic evolution of the Godavari basin is envisaged. Absence of volcanism, and the narrow rift zones, place the Godavari Graben in the 'Crevice' type of platform rift zone of Milonovsky (1972).
Post-Triassic Earth Expansion Perhaps Caused by A Cometary Impact in Tibet
Authors: Shields Oakley
Published: November 2024

Plate tectonic models for wide ocean basins in pre-Jurassic times do not agree with paleomagnetism, craton and orogenic belt coherence, and continental growth, nor to post-Triassic exponential increase in ocean surface area and great circle and antipode symmetries, while expanding earth models do. Rapid earth expansion since the Triassic may be due to a hypervelocity cometary impact in Tibet that fractured a continuous sialic crust into continents, initiating seafloor spreading and the Tethys Sea. The impact as ejected debris from an exploded rlanet between Mars and Jupiter agrees with Van Flandern's theory of comet origin.
Textural Characteristics of the Visakhapatnam Shelf Sediments
Authors: Satyanarayana Murty P. , Rao K. S.
Published: November 2024

Textural parameters, viz., mean, standard deviation, skewness and kurtosis and CM patterns in respect of 150 offshore sediments from the continental shelf off Visakhapatnam enabled delineation of two distinct sedimentary facies, one in the northern sector (Visakhapatnam - Bheemunipatnam) and the other in the southern sector (Visakbapatnam - Pudimadaka). The sedimentary facies in northern sector includes sands (from coast up to 37 m) followed offshore by silty sands (up to 50 m), sandy silt (up to 70 m) and silts (up to 80 m) and that in the southern sector, sands (up to 30 m), silty sands (between 30 - 40m and 50 - 80 m) followed offshore by sandy silts (between 40 - 50 m). There is a progressive seaward fining of sediments in the southern sector, whereas in the northern sector the fining is towards both sea and land. Fining of sediments with depth, a feature common to open shelves, is attributed to wave action. Distribution of medium sand zone in the northern sector between 15 to 40 m along the coast has been considered to be the result of dumping of dredged out material from the nearby port area. A major part of the study area is floored by poorly-sorted sediments. Skewness values of the sediments in the southern sector increase uniformly with depth whereas they show more complex pattern in the northern sector. Leptokurtic sediments bordering the coast in the northern sector indicate removal of fines through wave and current activity. CM diagram indicates the prevalence of low to moderate current activity in the south and highly turbulent zones in the north.
On Deciphering the Two Scales of the Regional Bouguer Anomaly of the Deccan Trap and Crust-Mantle Inhomogeneities
Authors: Mishra D. C.
Published: November 2024

Regional Bouguer anomaly over the Deccan Trap (south of Poena) is modelled, constraining it from Deep Seismic Sounding (DSS) studies. A regional, based on the normal Moho obtained from DSS studies along a profile, provides a broad 'hump' over the trap. The residual Bouguer anomaly consists of 'lows' which are modelled in the form of undulations of the Moho (37-41 krn) and Conrad (17-21 km) discontinuities and their rise towards the coast conforming with the DSS studies. These depressions of the Moho and Conrad discontinuities coincide with high plateaus on the surface on either side of river Bhima suggesting them to be caused by local isostanc compensation. The broad regional hump is attributed to the high density inhomgeneities in the upper mantle, approximately at a depth of 130-200 krn which also seem to be reflected in higher P-wave residuals in the teleseismic experiments conducted in this region. It is suggested that this upper mantle inhomgeneity could be due to the erosional unloading of the Deccan traps dod may represent some form of regional compensation. Therefore, two kinds of compensation are basically suggested in this region, namely, local in the form of variations in the level of the lower crust and regional in the form of high density mhomogeneity in the upper mantle. This analysis, therefore, does not support the suggestion of the existence of any sediment-filled rift valley under the traps in this region.
Cluster Analysis and Distribution of Recent Foraminifera, Araniar River Estuary, Tamil Nadu, India
Authors: Reddy A. N. , Reddy K. R.
Published: November 2024

Both living and dead Foraminifera were collected from 15 sampling stations in the Araniar river estuary, along the east coast of India for a period of one year. The distribution of the species has been studied with respect to time and space. Based on the Q-mode cluster analysis of the foraminifera, three major biotopes have been recognised, one of which has been subdivided into three sub-biotopes, based on the change in the level of correlation.
Characterization of Nickeliferous Laterite of Sukinda in Cuttack District, Orissa
Authors: Sahu K. C. , Venkateswaran D.
Published: November 2024

Weathering experiments have been carried out in laboratory with peridotitic rocks 10 understand the mechanism of mobilization and pattern of dispersion of nickel in vertical profile. Since goethite constitutes the principal mineral constituent in the nickeliferous laterite, synthetic goethite has been precipitated at various pH levels and in presence of varying nickel content in solution. The distribution of nickel in the precipitates has been recognised in terms of crystallinity and particle size of the goethite phase. The observation has been correlated with natural laterite samples collected from vertical profiles of Sukinda lateritic field. It is observed that while the amorphous hydrated iron-oxide has acted as a scavenger of cobalt and nickel from the precipitating solution, the nickel cations tend to inhibit crystallization of goethite. The present finding is considered useful for extraction of the metal from the lateritic matrix.
Godavari Delta System - A Wave-Dominated Delta System as Interpreted from Seismic Data has Hydrocarbon Potential
Authors: Dewan P. K.
Published: November 2024

Modern deltas can be classified mainly into three types: fluvial dominated, wave dominated and tide-dominated delta. Geometry of shoreline and palaeoshore line, dominance of strand-plain environment and other geomorphological and sedimentological features indicate the present Godavari delta to be wave dominated delta system. Seismic reflection patterns are predominantly parallel to subparallel, indicative of delta plain environments. Progradational shingled and oblique (parallel) reflection configuration is observed in different seismic sequences. Stratigraphic hydrocarbon reservoirs can be expected in wave-dominated environment.
Neogene-Quaternary Boundary in the Siwalik of Northwest Himalayan Foothills, India
Authors: Ranga Rao A.
Published: November 2024

Magnetic Polarity stratigraphy of the Upper Siwalik has been worked out along four traverses on the Surin-Mastgarh anticline, Jammu and Kashmir State. Fission-track dating of the bentonite beds allows correlation to the accepted magnetostratigraphic scale and identification of the Olduvai Normal Subchron in the Upper Siwalik sections.

The Vrica section, Italy, is now selected as the Pliocene-Pleistocene Boundary stratotype and the Pliocene-Pleistocene boundary is fixed above the Olduvai at 1.64 Ma, In the Upper Siwalik, at 1.64 Ma, there is no change either in the mammalian fauna or in lithology and life and sedimentation appears to have continued without any change. On the otherhand, a faunal change occurs at the Gauss-Matuyama transition dated at 2.48 Ma which is correlated to Tatrot-Pinjor faunal boundary. It is, therefore, suggested here that it is more practical to make the Pliocene-Pleistocene Boundary in the continental Siwalik to coincide with the base of Pinjor faunal boundary.
The Archaean Komatiites of Nagamangala Supracrustal Belt, Karnataka
Authors: Srikantia S. V. , Venkataramana P.
Published: November 2024

The meta-ultramafites of the Archaean Nagamangala belt of Karnataka craton display pillow structures and have kornatiitic chemistry. This is in conformity with other ancient supracrustals of Karnataka craton having komatiitic association.
Textural Study and Depositional Environment of Sand Grains from Rocks of Jaisalmer Formation, Jaisalmer District, Rajasthan, India
Authors: Mahender K. , Banerji R. K.
Published: November 2024

The textural parameters of sand grains from rocks of Jaisalmer Formation were systematically analysed for reconstruction of the depositional environment. These sands are fine- to medium-grained, moderatety sorted to well sorted, negatively to positivety skewed, and leptokurtic, The variations in mean size, sorting, skewness and kurtosis indicate a change in environmental energy conditions. The environmental interpretations based on various bivariate and multivariate plots of size and shape parameters indicate river transportation of these sands and deposition in a beach- to shallow-marine environment. The surface textures of these sand grains reveal transportation in an aqueous media and deposition in a shallow-marine littoral environment. The subangular to subrounded shape and the presence of abundant feldspars and mica show that these sands are less matured and have undergone little of transportation mostly through saltation process from a nearby source.
Record of Redlichiid Trilobite from tbe Lower Cambrian Tal Formation, Mussoorie Syncline, Lesser Himalaya, India
Authors: Mathur V. K. , Joshi Ashutosh
Published: November 2024

This note records the presence of the Lower Cambrian trilobite Redlichia noetlingi and an unidentified trilobite in association with brachiopods from the basal part of the Phulchatti Member of the Tal Formation in the Mussoorie Syncline, Uttar Pradesh.
The Nature of Bedrock at Petermann I, Wohltbat Range, Antarctica
Authors: Hussain S. M.
Published: November 2024

During the 6th Indian Scientific Expedition to Antarctica, geological and geochemical studies were carried out in the Schirmacher oasis and the Petermann I areas of Wohlthat ranges in Antarctica. The greasy-looklng porphyroblastic bedrock of Petermann I area described in this report ranges in composition from 'quartz-alkali feldspar syenite' to ' alkali-feldspar granite'.
Evaluation of Some Petrophysical Parameters for the Lower Cretaceous Reservoir Rocks, Western Desert, Egypt
Authors: El-Sayed Land A. A. , El-Dairy M. D.
Published: November 2024

Water saturation in otherwise hydrocarbon-saturated sandstones is closely related to the sandstone's clay mineralogy. Laboratory analysis of 20 sandstone core samples containing kaolinite, illite and chlorite is used to provide the basis for deciding which petrophysical parameters are most suitable for evaluating clay mineral content and distribution. Among the measured petrophysical parameters, the Mounce potential gives the most realistic correlation with actual clay mineralogy.

The existence of both siderite and hematite as cementing materials within the Kharita sandstone pore spaces, reduces the cation-exchange capacity of clay minerals by a clogging action. Consequently, the Mounce potential has been diminished. Correlations of the measured petrophysical properties have been elucidated to throw some light on both the Alam El-Buieb and Kharita reservoir rocks.
A Reinterpretation of the Geology and Biostratigraphy of the Lower Tertiary Formations exposed along the Bilaspur-Shimla Highway, Himachal Pradesh, India
Authors: Batra R. S.
Published: November 2024

The present paper offers a new interpretation of the geology and biostratigraphy of the Lower Tertiary Formations exposed on the Bilaspur-Shimla Highway, Himachal Pradesh. The structural interpretation of the frequent repetition of the Subathu-Dagshai Formations have been made in the light of presently recognised faunal zones in the upper part of the Subathu Formation. Geological mapping, coupled with palaeontological observations. reveal that the repetition of the Subathu (Green facies cf. Raiverman and Raman, 1971) and Dagshai (Red facies cf. Raiverman and Raman, 1971) Formations on the BiJaspur-Shimla Highway can be better explained by folding and faulting instead of facies intertonguing.
Comparison of Burial Diagenesis in some Deltaic to Shallow Marine Reservoir Sandstones from Different Basins
Authors: Imam Md. Badrul
Published: November 2024

Strikingly similar diagenetic histories of the deltaic to shallow-marine sandstones from the Bengal basin, the Gulf Coast basin, the Denver basin and the North Central Texas, have been noted. The diagenetic events include an initial phase of compaction and cementation with sequentially developed authigenic clay rims, quartz overgrowth and calcite cements, a secoud phase of secondary porosity development by rock component dissolution and a final less important phase of recementation with kaolinite and 'other cements. All the sandstones have comparable detrital composition and textural properties. Similarities. in depositional environments have contributed to establish similar set of facies relationships among sandstones and shales in terms of sand body geometry. sand-shale ratio, sedimentary texture etc. in these sequences. Inorganic and organic diagenetic reactions in shales have influenced the composition of their contained water that migrated during compaction into the adjacent sandstone into which mass transfer from shales is supposed to have taken place. The above factors presumably . lead to similar sort of fluid flux and fluid composition in the sandstones, meaning that the pore fluid evolution in the above sandstones have common links. It is envisaged that these common links are perhaps responsible for the similarities in the diagenetic events in all these sandstones.
Mineragraphy of Gold-quartz-Sulphide reefs of the Mangalur Greenstone Belt, Karnataka
Authors: Ugarkar A. G. , Tenginkai S. G.
Published: November 2024

Gold mineralization of gold-quartz vein-type is confined to narrow shear zones in the metabasic volcanic suite of the Mangalur Greenstone Belt. The dominant sulphide phase associated with the gold mineralization is pyrrhotite-pyrite assemblage followed by arsenopyrite, chalcopyrite and sphalerite in the decreasing order of abundance. Gold occurs in native state and within quartz.
Origin and Evolution of the Kalijhora Point Bar on Tista River, Darjeeling District, West Bengal
Authors: Chakraborty Shampa , Chakraborty Sujit K.
Published: November 2024

A point bar about 1.83 km long on River Tista shows gravel, ranging in size from pebble to boulders shows horizontal bedded structure forming the dominant sediment type. A largely upper flow regime condition is indicated. Comparison of maps prepared at different times indicates the bar to be stable in location but undergoing only changes in shape.
Geochronology of Miliolite Rocks of Kutch, Western India
Authors: Baskaran M. , Deshpande S. V. , Rajaguru S. N. , Somayajulu B. L. K.
Published: November 2024

Preliminary geochemical, mineralogical and geochronological studies using 230Th/234U method, of nine rniliolite rocks from Kutch are reported. The Kutch miliolites are characterised by lower CaCO3and higher quartz contents compared to their Saurashtra counterparts. The range of ages for the Kutch and Saurashtra miliolites are same and both can be accommodatedin the 50-70, 75-115 and > 140 K. Yr age groups proposed by Baskaran (1985).

The origin of the Kutch miliolites, like those of Saurashtra, appears to be marine. Theories to explain their occurrence in Kutch have to await more detailed studies of this type alongwith ichnological and petrographic observations.
Significance of Syndepositional Tectonics in Facies Development, Gangetic, Alluvium near Kanpur, Uttar Pradesh
Authors: Singh Indra Bir , Bajpai V. N.
Published: November 2024

Gangetic Plain, an active foreland basin shows N to NE flowing rivers in the southern part, controlled by the basement lineaments; while in the central part most of the rivers flow SE to E, following partly the lineaments developed in response to the Himalayan tectonics. Analysis of the subsurface data in Hamirpur-Kanpur-Unnao region shows that just south of present-day Ganga River, along an E-W trending lineament major change in the alluvial thickness and facies has taken place. It is suggested that earlier (probably Middle Pleistocene) rivers from Peninsular India flowing upto Kanpur, shifted their course southwards, and onlapped by Himalayan rivers and their deposits. It is argued that in 'an active foreland basin, lineaments parallel to orogen may develop, some of them even as gravity faults affecting the basement. These lineaments have a strong control on drainage, and thickness of the alluvial fill.
Upper Bhander Sandstone: An Example of Barrier Beach Deposits from Tantpur area, District Agra, Uttar Pradesh, India
Authors: Bhardwaj B. D. , Mathur N. K.
Published: November 2024

The Upper Bhander Sandstone occurring in the Tantpur area consists of red, brown and dirty white orthoquartzite with intercalations of shales. The sandstone is texturally and mineralogically mature. The palaeocurrent pattern worked out with the help of primary sedimentary structures reveals that the direction of the sediment transport remained north-westerly. The coarsening upward of the sequence, sedimentary structures, elongated sand bodies and polymodal palaeocurrent pattern indicate that Upper Bhander sandstone sequence of the Tantpur area was deposited on a beach complex in a regressive shoreface environment.
On the Origin of Fusain in the Tertiary Coals of Meghalaya
Authors: Singh Mahendra P.
Published: November 2024

The fusain fragments separated from the Tertiary coals of Meghalaya were studied under a high performance Scanning Electron Microscope. The transverse view (across the bedding plane) of these charcoalified plant tissues shows the preservation of micro anatomical details together with complete absence of middle lamella leading to cell-walls homogenization. The homogenization of cell-walls suggests that fusain of these coals has originated due to the pyrolysis of woody tissues. Pyrolysis took place during the intermittent dry seasons by the generation of forest fires in the basin. Disappearance of middle lamella zone from the cell-wall points that charcoalification temperature was 400°C. Further, charring of wood at a high temperature is indicative of the high oxygen level during the development of coal facies.
Investigation of Idukki Earthquake Sequence of 7th-8th June 1988
Authors: Singh H. N. , Raghavan Venkatesh , Varma A. K.
Published: November 2024

The epicentres of Idukki earthquake sequence of 7th-8th June 1988 which was widely felt in southern peninsular India, has been investigated. They are confined to a small area around 9°48'40" N and 77°11'10"E. A maximum Intensity VI on the MM scale has been assigned in the epicentral region of the main shock. Magnitudes of 4.5, 4.1 and 3.4 have been estimated based on signal duration for the main shock and two significant aftershocks respectively. The studies carried out have indicated that the earthquake is associated with major lineaments. Possibility of earthquake being triggered by the Idukki reservoir is remote.
Singhbhum Copper Belt: Copper concentration in Plants
Authors: Shyam A. K.
Published: November 2024

The copper content in plant and soil has been evaluated. Among the different species, Holarrhena antidysenterica Wall., Hyptis sauveolens Poit and Rostellularia prostrata (Clarke) Mazumdar excel in their copper accumulating ability along the belt.
Marine Minerals in the Indian Ocean
Authors: Roonwal G. S.
Published: November 2024

It is apparent that while knowledge of distribution of marine mineral resources. in the Indian Ocean has increased substantially over the last decade, actual production is restricted to placer, precious stones and aggregates, as well as to salt and chemicals. from seawater. The anticipated development of deep-sea minerals such as manganese nodules has not taken place and is unlikely to do so in the forseable future. One reaSOD is the lack of information for the proper evaluation of marine minerals. There is considerable scope for the systematic survey of both the EEZ as well as the deeper parts of the ocean to make a realistic assessment of the mineral resources and the development of technology for their eventual recovery.
Study of Muscovite from Pelitic Schist of Doda Area, District Doda, Jammu and Kashmir, India
Authors: Gupta L. N. , Guha D. B.
Published: November 2024

Muscovites separated from pelitic schists of the Dada area show a limited range of composition between ideal muscovite and ferrimuscovite. The paragonite content in the muscovites ranges between 14 and 21 %. The tetrahedral Aliv increases with the increase in the grade of metamorphism though this increase is more for the muscovite of the aureole rock, i.e., in the andalusite to staurolite zone than in the kyanite-staurolite zone. Similar results are also shown by the (FeO+Fe2O3) and Na/(Na+K) with respect to AI2O3 and total Al respectively.
Oxygen Isotopic Composition of Archean Orthogneisses and Charnockites from Southern India
Authors: Condie Kent C. , Longstaffe F. J.
Published: November 2024

The oxygen isotopic composition of Archean orthogneisses and charnockites from Southern India is rather uniform (δ18O generally 6-8%) for metamorphic grades ranging from amphibolite to high-P granulite. Some high-P granulites have high δ18O~ 10%) suggesting sediment contributions. CO2 metamorphism does not appear to have affected the δ18O values of Indian charnockites.
Tectonic Phases and Crustal Evolution in a Part of the Eastern Chotanagpur Gneissic Complex
Authors: Baidya Tapan K. , Maity Nabakumar , Biswas Parimal
Published: November 2024

The area in and around Jabarban-Belamu (23°25' - 23°29'N, 86° - 86c05'E) of the Purulia district, West Bengal, bears evidences of polyphase deformation, metamorphism and magmatic activity in the eastern Chotanagpur complex. At least four phases of deformation are imprinted on the rocks since the sedimentation ( ∼ 2300 Ma) of the metasedimentaries up to the last phase of granitic activity (∼800 Ma). A regional north-south compression was responsible for the development of isoclinal or tight F1 and F2-foIds with nearly east-west axes and overturning towards south. Ultrametamorphism of the older sediments during the acme of F1-deformational phase formed the anatectic granitoids and migmatites. Younger plutonic granitoids were emplaced in the axial zones of the F2-folds. Nearly east-west compression during the third deformational phase caused north-south trending open type cross folds (F3). Pegmatites and hydrothermal veins were mostly synkinematically emplaced in the ENE-WSW trending shear zone developed during the fourth phase of deformation. These features serve to illustrate the evolution of the Chotanagpur Complex in the Eastern Indian Shield.
A New Technique for the Determination of Homogenization Temperatures of Fluid Inclusions
Authors: Kaul I. K. , Rao C. N. , Sanyal T.
Published: November 2024

A new technique to determine the homogenization temperatures of fluid inclusions is described. The technique is based on the principle of optical density and involves no ambiguity in recording homogenization temperatures unlike in the standard heating stage method where because of problems of visual clarity of liquid phase disappearance, accurate measurement of homogenization temperatures becomes difficult and unreliable. A comparison of the two methods shows that the present technique gives somewhat higher values than those based on heating stage method.
Seismic Stratigraphy of Godavari Basin Leading to a Discovery of a Carbonate Buildup, a Probable Reservoir for Oil
Authors: Dewan P. K.
Published: November 2024

The paper gives a three dimensional view of Godavari coastal basin, India, a pericratonic basin, for exploration of hydrocarbons based on seismic stratigraphic interpretation. The whole pile of sediments is divided into three seismic sequences. These seismic sequences are correlated with lithology from well data and outcrop stratigraphy.

Each seismic sequence is divided into various seismic facies based on reflection configuration, amplitude and continuity representing different environments of deposition and energy conditions. The seismic facies recognised are parallel to subparallel reflection configuration with high continuity and high amplitude, low continuity and low amplitude and low continuity and variable amplitude; divergent reflection configuration; progradational reflection configuration including oblique progradational, shingled progradational and hummocky progradational and chaotic reflection configuration.

In seismic sequence 2, patch of carbonate buildup-a probable hydrocarbon reservoir is mapped and a well location is recommended. Carbonate buildups are found to be good stratigraphic traps for oil and gas because of their good permeability and affinity to organic material. They have been reported from all over the world including Bengal basin in India.
Hummocky Cross-Stratification and its Hydraulic and Climatic Implications in Talchir formation, Dudhi Nala, Hazaribagh, Bihar
Authors: Bhattacharya H. N. , Mukhopadhyay G. , Bose Pradip K.
Published: November 2024

Storm products are exceedingly rare in glacio-marine and -Iacustrine sequences. However, glacigenic Permo-Carboniferous Talchir sequence in Dudhi nala, West Bokaro coal basin, Bihar, registers two distinct hummocky cross-stratified facies units of considerable thickness. This, in turn, suggests the activity of storm waves vis-a-vis the removal of iceberg cover and considerable amelioration of climate during Talchir times.
An Analysis of the Structures in the Beawar-Barr Section, Delhi Fold Belt, Central Rajasthan
Authors: Dasgupta A. , Bhattacharya P.
Published: November 2024

Strain analyses of deformed pebbles of the conglomerate horizon at Barr, reveal that they have undergone a flattening type deformation with about 80% of the pebbles showing 1>K>O and the corresponding Lode's ratio (ν) between 0 and 1. These results reveal that the principal stresses acted across the main strike of the belt and the strain factor was directed sub-vertically. These inferences were further applied to analyse the various fold structures observed in this region. This led to the conclusion that although three phases of folding are seen, the deformation of the Delhi Supergroup rocks took place in two stages. The first stage brought in major deformation of the rocks, the formation of F1 folds and the deformation of the conglomerate pebbles. F2 folds, superposed on the F1 fold structures, are observed only along the margins of the Delhi fold belt. The spatial distribution of the F2 folds and their geometry suggests that, they were formed due to local reorientation of the stress and strain axes during the same deformation stage. The second stage of deformation resulted in the formation of diagonal shear zones along which right-hand shearing gave rise to the F3 fold structures.
The Stratigraphy of the Kinnaur Tethyan Basin - A Reappraisal
Authors: Bassi U. K.
Published: November 2024

The geological database of the Phanerozoic Kinnaur Tethyan Basin in Himachal Pradesh is updated and its lower Palaeozoic lithostratigraphy revised to bring uniformity with the Spiti Basin. The paper also records the occurrence of middle Palaeozoic-Mesozoic rocks for the first time from the Baspa Valley. Some observations on the validity of certain fossil reports from this basin have also been made.
Geochemistry of Felsic Volcanics from Gurapratap Singh and Diri, Pali Dist., Rajasthan (Part - II, Trace Elements)
Authors: Srivastava R. K. , Maheshwari A. , Upadhyaya Rajani
Published: November 2024

Felsic volcanics of the Gurapratap Singh and Diri, belong to the Malani volcanic suite of Precambrian age. Major element chemistry of these volcanics shows systematic variations with progress of differentiation. The distribution and behaviour of trace elements in these rocks is in accord with their major element data and the distribution patterns are normal with no anomalous concentrations of the elements studied. With the progress of fractionation there is a smooth decrease in Sr and increase in Rb which along with Ba are the main trace contents of these rocks. Unlike Sr and Rb which have a linear distribution pattern, Ba shows a curvilinear trend, i.e., an initial increase from andesite to dacite and rhyodacite followed by a decrease amongst rhyolites. The behaviour of ratios like Ni/Co, Fe/Zn, Mg/Li and K/Rb agrees with a model of fractional crystallisation. Furthermore, the trace element abundances of the volcanics point to their crustal source. The work also shows that in felsic magmas Ba and Sr are sensitive indicators for tracing possible differentiation and that rhyolitic rocks depleted in Ba are enriched in Rb and that in last stages of differentiation Ba/Rb ratio shows rapid decrease.
K-Ar Ages on Three Basic Intersecting Dykes from Gadag Schist Belt, Karnataka
Authors: Gokhale N. W. , Waghamare B. P.
Published: November 2024

About 200 basic dykes traverse the northern part of the Gadag Schist Belt. Out of these, three dykes show distinct cross cutting relations with each other. K-Ar geochronological studies indicate ages of 1535±61 m.y. for the oldest dyke, 1082±54 m.y. for the intermediate dyke, and l018±50 m.y. for the youngest dyke.
Eotomariidae Gastropod in Talchir Formation of Ramgarh Coalfield and its Paleoenvironmental Significance
Authors: Chaudhuri S. , Mondal K.
Published: November 2024

External mould of gastropod, Platyteichum sp. occurs in Talchir siltstone in Ramgarh coalfield. A marine event is clearly indicated.
Petrochemistry and Geochronology of Pink Granite from Songsak, East Garo Hills, Meghalaya
Authors: Kumar Sunil
Published: November 2024

The pink granite of Songsak area, East Garo Hills district, Meghalaya, intrusive into Precambrian gneisses is inferred to be S-type, peraluminous, low calcium, postkinematic granite. It is characterised by initial 87Sr/86Sr ratio of 0.728±.002, high K20, high differentiation index and presence of normative corundum. The major mineral constituents are perthitic microcline, fresh interstitial microcline, orthoclase with different degree of triclinisation, two generations of quartz and biotite. Sericitization of feldspars, presence of muscovite, rare chiastolite, fluorite and uraninite are other characteristics of the pink granites. Whole rock Rb-Sr dating assigns an age of 500±40 m.y,
Mineralogical and Petrological Studies of Gneisses and Charnockites of Dharmapuri District, Tamil Nadu
Authors: Rameshwar Rao D. , Narayana B. L. , Charan S. N.
Published: November 2024

Detailed mineralogical studies of amphibolite to granulite facies transition zone rocks and granulite facies rocks in Dharmapuri district, Tamil Nadu, were carried out in order to know the gneiss-charnockite relations, nature of protolith, and metamorphic conditions.

The studies show that the rocks are of magmatic origin. and show a gradual decrease in modal composition of hornblende and biotite and gradual increase of hypersthene and iron oxide in a north to south traverse. Breakdown of hydrous minerals to anhydrous minerals is evident with the release of iron oxide suggesting progressive transformation of gneisses to charnockite, Biotite occurs in two generations, an earlier one is of massive type and breaks down to anhydrous minerals, while the latter one occurs as tabular flakes and likely to have formed during the waning stages of amphibolite to granulite facies metamorphism, and forms a zone of concentration just above the stage or CO2 migration. The mineralogy of pyroxene, plagioclase, hornblende, biotite and iron oxides also suggests that the pressure-temperature conditions in the transition zone are lower than those of the granulite zone.
Geology Along the National Highway-IA Between Batote and Qazigund, Jammu and Kashmir State
Authors: Razdan M. L. , Dhir N. K.
Published: November 2024

The section along the National Highway-IA between Batote and Qazigund, in the Jammu and Kashmir Himalaya exposes a succession of rocks ranging in age from Precambrian to Tertiary which fall under three tectonic divisions viz, the Murree Structural Belt, the Lesser Himalayan Belt of J and K and the Kashmir Tethyan Belt, separated from each other by major tectonic discontinuities designated as the Murree Thrust and the Panjal Thrust.
Effects of 1950 Earthquake on Geomorphology and Ecology in a Part of Brahmaputra Valley Near Teju, Arunachal Pradesh
Authors: Ramesh N. R. , Gadagkar N. S.
Published: November 2024

The paper reports evidences of some important geomorphological and ecological changes recorded during the recent Quaternary investigations, in the alluvial area immediately west of Teju in Lohit district, Arunachal Pradesh and Dibrugarh district, Assam, triggered by 1950 Earthquake.
Structural Trendline Patterns and Lineaments of the Western Ghats, South of 13° Latitude
Authors: Nair M. M.
Published: November 2024

Lithological boundaries and co-parallel axial planar fabric of the earliest isoclinal folds have contributed the treodline features observed. Based on the nature and style of folding, persistence, frequency and discontinuity of trendlines, eight distinct structural domains have been identified.
Morpho-Chemistry of Some Ferromanganese Samples from Central Indian Ocean Basin
Authors: Mohapatra B. K. , Misra S. K. , Sahoo R. K.
Published: November 2024

This note is aimed at elucidating the relationship between morphology and chemistry of some ferromanganese samples of Central Indian Ocean basin and describing precisely the factors controlling these variations. The samples investigated were dredged from Central Indian Ocean basin at a depth of 4000-5000 m during cruises of SS Fernela (St. F4 and F5), SS Scandy Surveyor (St. SS4, SS5, SS6 and SS8) and RV Sagarkanya (St. SK8) conducted by the National Institute of Oceanography, Goa. Because of certain restrictions, location of sample details have not been mentioned.
Formation of Phosphatic Coated Grains and Peloids by Grain Diminution of Precambrian Apatite Crystals
Authors: Dahanayake Kapila , Subasinghe S. M. N. D.
Published: November 2024

Due to tropical physical and chemical processes active on a Precambrian apatite marble formation, primary apatite crystals were removed from the parent rock and deposited in different types of depressions within a thick weathering profile. The primary apatite crystal margins show a microcrystalline envelope characteristic of coated grains. The envelope may extend towards the centre of the grain eventually forming a wholly microcrystalline apatite body out of the initial coated grain, thus producing a peloid by the process of grain diminution.

Microbial mats grow within the depressions engulfing the primary apatite crystals. coated grains and peloids of variable size. Continuous surficial processes together with subsurface percolation of sediment and nutrient-rich waters help to maintain the growth of the laminated stromatolitic groundrnass. Grain diminution seems to play an important role during diagenetic process in the phosphate micro-sedimentary environment of the depressions within the apatite marble formation. The grain diminution of Precambrian single apatite crystals to form a phoscrete-type phosphorite is perhaps a unique phenomenon.
Origin and Significance of Hemavathi-Tirthahalli Mega-Lineament
Authors: Ganesha Raj K.
Published: November 2024

LANDSAT MSS False Colour Composite on 1 : 537,000 scale has been interpreted to study the lineaments in the study area (Frame 145-051 covering Hassan, Chikmagalur, Kodagu, Shimoga, Mysore, Dakshina Kannada, Tumkur, Chitradurga Districts of Karnataka and Kasaragod District of Kerala). The most prominent lineament is about 190 km long and is named Hernavathi-Tirthahalli mega-lineament. The direction of this mega-lineament is almost parallel to the west coast. This mega-lineament with considerable length and almost parallel orientation to the west coast indicates that it developed at the time of the West Coast Fault. Major lineaments like Yagachi, Tunga and a good number of other lineaments are also parallel to the west coast. As most of the earthquakes (between 1967 and 1977) in Southern Peninsula occurred in the vicinity of NNW-SSE to NW-SE trending mega lineaments, the Hemavathi-Tirthahalli mega-lineament should be studied to understand its seismic status.
Study of Intensities of 26th April 1986 Dbaramshala Earthquake (Himachal Pradesh) and Associated Tectonics
Authors: Kumar Surendar , Mahajan A. K.
Published: November 2024

A moderate earthquake of magnitude 5.5 on Richter scale rocked the Dharamshala area in Himachal Pradesh on 26th April 1986 at 07.35 : 17 GMT. The earthquake was felt in Kangra valley, Kullu, Mandi and Chamba areas. Dharamshala town, Macleodganj and Naddi etc., were subjected to maximum damage where the mud houses, older buildings and some of the Govt. buildings suffered maximum loss. Cracks along mortar joints, fall of plaster and relative movement of walls were observed in a number of residential buildings. On the basis of study, four isoseisrnals of VII, VI, V, IV intensities on the MMscale have been drawn. The shape of these isoseismals is elliptical and based on this, the NW/SE trending epicentral tract of this earthquake has been estimated to bel oeated just at Dharamshala Town. With the land levelHng survey and field observation of cracks and fracture, the direction of movement and direction of fracture is also shown. Local depth distribution of earthquake in the Dharamshala area suggests that fractures causing this earthquake have. direct relationship with the local thrust faults.
New Names for Loxoconcha and Semicytherura Species from the Quilon Beds of Kerala
Authors: Khosla S. C. , Nagori M. L.
Published: November 2024

It has been brought to our notice by Professor E. K. Kempf, Federal Republic of Germany that the names of two new ostracode species - Loxoconcha (Loxoconclra) subalata and Semicytherura indica - recently described by us (Khosla and Nagori, 1989, pp. 46-47, 50) are preoccupied by Loxoconcha subalata Brady, 1911 and Semicytherura indica Neale and Singh, 1985, respectively. As both our names are primary junior homonyms they are rejected and replaced by Loxoconcha (Loxoconchas) keralaensis Khosla and Nagori, and Semicytherurapadappakkaraensis Khosla aad Nagori.
Cretaceous Planktonic Foraminifera from the Cherty Limestone of Baratang Island, Andaman, India
Authors: Rajshekhar C. , Badve R. M. , Kundal P.
Published: November 2024

Late Cretaceous planktonic forarmruferal species viz, Guembeluna cretacea Cushman, Pseudoquembehna excolata (Cushman), Ventilabrella sp, Globigerinelloides sp , Hedbergella delrioensis (Carsey), H planispira (Tappan), Globotruncana concavata (Brotzen), G marginata (Reuss), G of rosetta and Rugoglobigerina macrocephala Bronnimann are reported from cherty limestone of Baratang Island, Andaman. The assemblage indicates dominance of Maestrichtian element Based on recorded stratigraphic ranges of different species the cherty limestone is assigned a Campanian-Maestrichtian age.
Void Ratio and Porosity of the Bank Soil Around Maijan and Mathola, Dibrugarh District, Assam
Authors: Ahmed Hasan , Maswood M. D.
Published: November 2024

The void ratio and the porosity of the bank soil around Maijan and Mathola are from 0.32 to 1.38, and from 0.29 to 0.58, respectively, and show the characteristic of soft clay. In the top clayey soil with higher void ratio and porosity, consolidation has not occurred. The heavy water pressure with the underlying sandy soil with less void ratio and porosity has promoted erosion of the river banks.
Quartzites of the Cuddapah Group and Their Environment of Deposition
Authors: Pulla Reddy V. , Subba Reddy N. , Prasad C. V. R. K.
Published: November 2024

Quartzites occurring at different stratigraphic levels in the Proterozoic Cuddapah Group are studied for petrography, chemistry and grain size distribution for purposes of comparison and determination of the environment of deposition. It is indicated that these formations were laid down in a beach environment and that they were subjected to tectonic disturbances before the Srisailam sediments were deposited. This resulted in the less mature nature of the Srisailam quartzites compared to all other quartzites underlying it.
Quick Quantitative Appraisal of Groundwater Resources - Case Study on 'Coconut Triangle', Sri Lanka
Authors: Ramesam V.
Published: November 2024

Based on different methods of quick quantitative appraisal, the recharge to the groundwater body is estimated to be around 150 mm per unit area per annum. The potential evapotranspiration varies from 1170 mm to 1340 mm. The run off is about 1 MCM per sq. km per annum in the Maha Oya basin and decreases to 0.4 MCM per sq. km per annum in the Deduru Oya basin. Unclassified granite gneisses, khondalites and charnockites occur over alargc part of the area. Groundwater occurs in the weathered and fractured parts of the hard rocks and in the intergranular pore spaces in the Quaternary formations under unconfined to semi-confined conditions. The water levels vary from 1 m to 15 m below ground level. The groundwater recharge occurs two times in a year - in May-June and again in November-December. The quality of water is good with tbe electrical conductivity being Jess than 300 micromhos/cm at 25°C.
Coccoliths in Barakar formation of Ramgarh Coalfield, Bihar
Authors: Chaudhuri S.
Published: November 2024

A few coccoliths are being reported from the Barakar sediments of Ramgarh coalfield. These point to marine environment, though of not precisely known time. A Lower Gondwana affinity of these cannot be ruled out.
Acoustic Wipeouts Over the Continental Margins of Krishna, Godavari and Mahanadi River Basins, East Coast of India
Authors: Murthy K. S. R. , Rao T. C. S.
Published: November 2024

Loss of seismic reflections, termed as acoustic wipeouts, are observed in the high resolution sparker seismic records over the continental shelf and slope of Krishna, Godavari and Mahanadi river mouths, east coast of India. The wipeouts observed in the sub-surface layers beneath the outer shelf off these basins (150 to 250 m water depth) result in a chaotic appearance, probably indicating the presence of gas mixed sediments, while those observed over the continental slope (beyond 500 m water depth) are mostly associated with faulted contacts and uplifts and represent an abrupt weakening of seismic energy or break in the pattern of surface and/or sub-surface reflectors. Though acoustic wipeouts result due to a variety of reasons, their association with vertical faults and location at depth off major river basins suggest that some of these might be due to migration of oil/gas along the faulted contacts from increased depths.
Himalayan Palaeontologie Database Polluted: Plagiarism and Other Anomalies
Authors: Talent John A. , Brock Glenn A. , Engelbretsen Michael J. , Gaetani Maurizio , Jell Peter A. , Mawson Ruth , Talent Ross C. , Webster Gary D.
Published: November 2024

Additional evidence is presented regarding spurious localities, plagiarised illustrations and other forms of disinformation injected into the Himalayan palaeontologie and stratigraphic database in the past 25 years, all connected with a single source.
Linear Ash-Moisture Relation of Coal Seams in a Borehole Drilled in Chuperbhita Coalfield, Bihar
Authors: Madabhushi Srinivas
Published: November 2024

Six regional seams and six local seams were intersected in a borehole RJC-10 drilled during April-July 1976 in Chuperbhita coalfield of Rajmahal hills, Bihar. The Ash-Moisture relations of these seams is strikingly linear in this particular borehole. A correlation with lithofacies has indicated that RJC-10 is in a zone of relatively lower Sandstone/Shale and Clastic ratios. The water of hydration of inorganic constituents present as combined water of 'hygroscopic' moisture in the finer sediments could have been expelled in a gradual and linear manner with increase in depth.