bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sapphirine-Bearing Assemblages from Perumalmalai, Palani Hills, Tamil Nadu
Authors: Sivasubramanian P. , Natarajan R. , Janardhan A. S. 
Published: November 2024

Abstract
A new find of sapphirine-bearing granulite rocks from Perumalmalai area, 15 km from Kodaikanal is reported. These rocks, contain in addition to sapphirine, cordierite-garnet-orthopyroxene-spinel-biotite-plagioclase. Among the pairs, garnetcordierite gives pressure of 8.5 kb at temperature of 550°C; garnet-orthopyroxene gives 6 kb at 800°C and cordierite-garnet-sapphirine gives 7.2 kb at 700°C. The sapphirineforming reaction probably took place after the main charnockite event. Evidences of decompression of garnet breaking down to orthopyroxene-spinel-plagioclase-biotite at rather high temperatures indicates rapid uplift.
Sargur-Dharwar Relationship Around the Komatiite-Rich Jayachamarajapura Greenstone Belt in Karnataka
Authors: Venkata Dasu S. P. , Ramakrishnan T. M. , Mahabaleswar B. 
Published: November 2024

Abstract
New geological and preliminary geochemical data presented here from J ayachamarajapura (JC Pura) reinforce the idea of orogenic separation of two sequences across a deformed angular un confonnity . The JC Pura belt forms a major structural dome linking a trail of enclaves to the north and south. Its main lithology is altered komatiites preserving excellent polyhedral joints, pillows, ocelli and spinifex texture. These peridotitic komatiites are closely associated with the basaltic komatiites now represented by dark shiny amphibolites.Cherty quartzites and BIF form minor units. This association is typical of the older greenstones (Sargur Group) of Kamataka. These lithologies are overlain unconformably by the basal quartz-pebble conglomerate and associated amygdular metabasalt - crossbedded quartz arenite alternations constituting the Bababudan Group in the Kibbanahalli arm of Chitradurga schist belt. Kibbanahalli volcanics are mainly tholeiites as distinct from the dominant komatiites of the JC Pura belt. Such chemical distinction, but of a different kind, is reported recently from the Kalasapura area of Bababudan belt. JC Pura area therefore offers yet another spectacle of Sargur-Dharwar orogenic discrimination in Kamataka.
Distribution and Geochemistry of Uranium in the Orcadian Rocks from Northeast Scotland: A Fission Track Study
Authors: Das Nachiketa , Mackenzie Angus B. 
Published: November 2024

Abstract
Fission track study on thin sections of whole rocks and separated minerals from different sedimentary facies of the lacustrine Orcadian basin, northeast Scotland has shown variations in uranium distribution in different facies which can be correlated with the prevailing redox conditions during deposition. Uranium in sandstones is associated exclusively with detrital grains of apatite and zircon but not with any authigenic phase indicating oxidizing environment. In contrast, in shales and dolostones very little uranium is associated with detrital zircon and apatite, and mostly occurs either adsorbed on grain surfaces or incorporated in the crystal structure of the authigenic minerals and organic matter pointing to reducing environment.
Podiform Chrolnites in Mantle Peridotites from Indus Ophiolite Belt, Ladakh Himalaya
Authors: Dessai A. G. , Karmalkar N. R. , Leblanc M. 
Published: November 2024

Abstract
Peridotites in ophiolites from Ladakh Himalaya occur as disconnected slices within an ophiolite melange exhibiting faulted, sheared and tectonic contacts. Chromite occurs as pods, schlieren banded as accessory ore within dunites. The pods are generally concordant to semiconcordant to the foliation of the host dunites. In places, however, they are discordant to the foliation. The chrome spinels (sensu lato) exhibit bimodal distribution. Those in harzburgite conform to Type I alpine type peridotites. Whereas the ones from dunite are akin to Type III peridotites as classified by Dick and Bullen (1984). The spinels from wehrlites are compositionally similar to those from ophiolite cumulates.
On the Active Tectonics of Dehra Dun Region from Observations of Ground Elevation Changes
Authors: Gahalaut V. K. , Chander R. 
Published: November 2024

Abstract
The data presented suggest that uplift of the outer Himllaya in this region is continuing even today through sudden co-seismic elevation changes during large thrust earthquakes and secular aseismic uplift during intervals between such earthquakes. The observed co-seismic ground elevation changes during the Kangra earthquake are interpreted so as to simulate the cross-sectional shape of the buried active thrust fault responsible for this continuing episodie as well as secular uplift of the Outer Himalaya. This fault is assumed to be the surface of detachment between the Himalayan rocks above and the Indian shield rocks below. It is concluded that over most of its extent in Dehra Dun region, the detachment surface has gentle dip to the northeast but a few interspersed, northeast dipping steeper ramps are not ruled out. The depth of the detachment is estimated to be between 0 and 3 km beneath the SW limit and about 10 km beneath the NE limit of the Outer Himalaya in the Dehra Dun region. The two main levelling observations regarding the current inactive status of the Main Boundary Thrust (MBT) are, (1) the involvement of this thrust in the occurrence of the Kangra earthquake is definitely ruled out from the levelling data, and (2) the measured rate of secular uplift of the ground increases from NE to SW across the surface trace of the thrust suggesting that the Outer Himalaya is rising faster than the Lesser Himalaya to the NE across the MBT.
Apatite Mineralisation around Beldih and its Genetic Control, District Purulia, West Bengal, India
Authors: Bhattacharya D. K. , Dasgupta S. 
Published: November 2024

Abstract
Apatite mineralisation occurs in the host rock chlorite phyllite which grades into chlorite schist and is granitised. Discontinuous veins of apatite within apatite-magnetite rock exhibit many morphological types. The apatites also contain tantalum, niobium, titanium, molybdenum and vanadium. Studies reveal that apatite mineralisation is controlled by both structure and lithology.
Theory of the Number of Hexagonally Distributed Points in a Given Circle and Its' Application to Study Fluid Inclusion Population
Authors: Nayak B. K. , Panchapakesan V. 
Published: November 2024

Abstract
The equation, N = 2πX2/√3, has been derived to find out the number of hexagonally distributed points (N), in a given circle of radius 'R' and the point-point distance 'd'. where X = R/d. For a given set of microscopic conditions, the above equation is applied to construct 4 standard circular graphic charts. An, attempt has been made to use these charts to study the population of fluid inclusions, by visual comparison, in the quartz samples intimately associated with the sulphides collected from the Mosaboni mine of Bihar.
A Turbidite Limestone-Shale Rhythmite of Sirban Limestone of Raisi, Northwest India
Authors: Gundu Rao C. 
Published: November 2024

Abstract
The couplet thickness of Raisi limestone-shale rhythmite is trend-free and non-oscillatory. The couplet thickness are log-normally distributed. These characters suggest, Raisi rhythmite is of episodic as against diagenetic and seasonally-controlled origin of the rhythmites. Among the options available for episodic origin (inundites. tempestites, turbidites) evidences suggest a turbidite origin for Raisi rhythmite.
Tourmalinite from Cu-U Belt of Singhbhum, Bihar, India
Authors: Bhattacharya H. N. , Chatterjee A. , Chowdhury Somnath 
Published: November 2024

Abstract
Tourmalinite occurs as a stratigraphically persistent unit in the Proterozoic Cu-U belt of Singhbhum, Bihar. Internally the tourmalinite is plane laminated with alternations of tourmaline-rich and quartz-rich layers, and is also cross-stratified. Tounnalinite breccia also forms a significant part of the unit. Preserved primary sedimentary features, amidst deformed and metamorphosed rocks, attest to a primary sedimentary origin of the tourmalinite. Close assocication of Cu-Sulphide mineralizations and tourmalinite suggests volcanogenic origin of the Cu-sulphide mineralization and precipitation of the tourmalinite from boron-rich exhalative fluids.
Marine Magnetic Indication of a Possible Submerged Volcano off Machilipatnam in Bay of Bengal
Authors: Venkateshwarlu P. D. , Sengupta B. J. , Raghava Rao A. M. V. , Bose P. K. 
Published: November 2024

Abstract
A pronounced magnetic (TF), anomaly zone, hitherto unreported. was located off Machilipatnam in the Bay of Bengal influencing an area of about 10,000 sq km, 2D-model studies suggest a hypothetical presence of a basic body (?) intruding the basement granites and gneisses.
Organic-Walled Microfossils from the Bedded Black Chert of the Krol Formation (Vendian), Solan Area, Himachal Pradesh, India
Authors: Kumar S. , Rai Vibhuti 
Published: November 2024

Abstract
Well preserved microfossils are reported from petrographic thin sections of the bedded black chert from the Krol 'A' Member of the Krol Formation near Solan. Himachal Pradesh. Filamentous forms comparable to Eomycetopsis Schopf, Siphonophycus Schopf, Obruchevella Reitlinger and coccoid forms represented by acritarchs and spheroid colonies showing resemblance with living cyanobacteria Microcystis Kutzing are recorded. The presence of forms comparable to Obruchevella suggests Upper Riphean to Vendian age to the Krol 'A' Member.
Peraluminous, Metaluminous and Alkaline Granites from Parts of Andhra Pradesh and Karnataka in the Dharwar Craton: A Critical Reappraisal of Existing Data
Authors: Sarvothaman H. , Leelanandam C. 
Published: November 2024

Abstract
Predominant rocks in the Medak-Nizamabad segment in Andhra Pradesh are of a granodiorite-adamellite-granite (GAG) suite; the Alumina Saturation Indices or the molar Al2O2/(CaO + Na2O + K2O) of these units indicate that they arc metaluminous. This suite contains inclusions of a peraluminous tonalite-trondhjemite (IT) suite. A younger peraluminous suite of K-rich granite, granite (s.s.) and adamellite (KGA) intrudes the metaluminous GAG suite and the peraluminous IT suite; a body of alkaline granite intrudes the peraluminous granites.
The tonalite-trondhjemite protoliths of the ca. 3000 Ma old gneisses of Kamataka are peraluminous, and the granites associated with them metaluminous. The Closepet granite activity began with the emplacement of mctaluminous granites, followed by the intrusion of peraluminous granites.
Partial melting (at lower to middle crustal levels) of charnockites, mafic granulites and basic lithologies may have generated the melts of metaluminous and alkaline granites. The ca. 3000 Ma old peraluminous granites are suggested to have formed by partial melting of basic rocks such as basalt and amphibolite under water-excess condition at lower crustal levels. Metaluminous granites, greenstone lithologies and the ca. 3000 Ma old peraluminous gneisses are the precursors for the peraluminous components of the Closepet granite and the KGA suite of Andhra Pradesh. The alkaline granite of Medak-Nizamabad is post-collisional and is emplaced in a rift-free setting.
The Incipient Charnockites of Transition Zone, Granulite Zone and Khondalite Zone of South India: Contrasting Mechanisms and Controlling Factors
Authors: Ravindra Kumar G. R. 
Published: November 2024

Abstract
Incipient charnockitisation in southern India is achieved through volatile action either during progressive metamorphism, or by progressive tectano-metamorphic activity, as in the Kerala khondalite belt. The initial inertness of some rocks to charnockitisation may be due to unsuitable bulk composition/mineralogy or high water activity or lack of sufficient fluid channels. Most workers advocate massive influx of CO2 from the mantle, for causing charnockite formation at lower levels and initiating anatexis at advancing front. The timing of CO2 influx and liberation of H2O and sequential reactions in the crust are important because they can account for the development of massive charnockites, the modification of supracrustals (metapelites etc.) by in-situ partial melting, or infiltration of alkali-rich fluid phases. the progressive build up of CO2 and patchy charnockite development. It is suggested here that the above processes operated in succession and are interrelated. It is further suggested that incipient charnockite formation in south India is not the result of one common mechanism or of a specific time related event, but is a local and independent response of rock types to changing P-T and fluid regime.
Pyroxenes from Alkaline Rocks of the Chhota Udaipur Carbonatite-Alkaiic Province, Gujarat, India
Authors: Viladkar S. G. , Avasia R. K. 
Published: November 2024

Abstract
The Amba Dongar, Sirivasan and Panwad-Kawant carbonatite-alkalic complexes have close spatial relation. In Amba Dongar olivine-free nephelinite is the predominent type of alkaline rock with a few phonolite dykes; in Sirivasan tinguaite is more abundant than nephelinilte while in Panwad-Kawant region bulk of the alkaline rocks is made up of phonolite and tinguaite. The chemistry of the pyroxenes of these alkaline rocks has been interpreted and their evolutionary trends are discussed. The pyroxenes of Amba Dongar and Sirivasan complexes show early acmitic trend with phenocrysts being more calcic. The groundmass pyroxenes are more acmitic. The pyroxenes of the Panwad-Kawant complex, on the other hand, are less evolved diopsidic-salite type, showmg only slight initial hedenbcrgite enrichment and the final aemitic enrichment. These two trends are attributed to varying crystallizing conditions of the two batches of the same magma.
Determination of the Flow Direction of Geothermal Waters at Manikaran using the Borehole Tracer Technique
Authors: Athavale R. N. , Rangarajan R. , Rao S. M. 
Published: November 2024

Abstract
Borehole tracer studies were carried out to determine the direction of flow of thermal waters in Manikharn hot-springs area. Inactive potassium iodide and radioactive bromine-82 were injected in one deep geothermal well (DGW) and tritium and bromine-82 were injected in another deep geothermal well on March 31 and April 1, 1984 respectively. Several wells and springs were monitored for a few days in the field itself for bromine-82 activity and samples collected from hot springs and wells over a period of three months were analysed in the laboratory for tritium and iodide. The results show a steeply high value for tritium in the sample collected on 6.4.1984 from a well located 350 m due south of the injection well and on the opposite bank of Parvati river. No significant concentration of iodide and Br-82 nor any discernible trend in their distribution was shown by any of the samples. Results of the multiple tracer injection study favour the model advocating movement of geothermal water from North to South. The velocity of flow through fractured and jointed quartzites was calculated as about 72 m/day.
On the Occurrence of Ediacarian (?) Dubiofossils in the Narainnagar Formation of Nainital Area, U.P., India
Authors: Misra S. B. 
Published: November 2024

Abstract
Narainnagar Formation constituting the uppermost part of the Krol Group of Nainital area contains a variety of imprints, some of which are suspect. The frond-like fonns in particular have superficial resemblance with the Ediacarian fossil Charniodiscus but on critical examination reveal features of mechanical nature. The imprints therefore can be classified, at best, as dubiofossils. The small round depressions interpreted earlier as rain drop imprints by some workers and as Beltanelliformis by others might be related to Chauria, if at all they are of organic origin. The attachment disc, though not found in intimate association of the frond-like structures, might prove significant in the interpretation of the forms. Publication of taxonomic classification of the imprints without proving first the organic character is premature.
Sedimentology of a Recent Alluvial Fan of Ganga River, Rishikesh, India
Authors: Bhardwaj B. D. , Singh Adal 
Published: November 2024

Abstract
The annual flow of the river Ganga is 468.7 billion cubic meters. The river emerges on the plain at Rishikesh from the mountains. The Alluvial fan deposits are divided into three facies: proximal, medial and distal fan facies. The nature of sediments varies from coarse gravel and boulders to fine gravel to coarse sand. The proximal facies show massive units (Gms) and coarsening upward of sediments. The gravel and boulders of proximal facies are randomly oriented and are poorly sorted, which are described as debris deposits. The sediments of mid fan facies show massive units (Gms), horizontal stratification (Gh) and planar cross-stratification (Gp). The sediments are moderately sorted and show imbrication. Distal fan Sediments are well sorted marked with trough cross-stratification (St) and gravelly channel deposits (Gs). The sediments of mid fan and distal fan facies show fining upward sequence and are described as water-laid deposits. The distal fan deposits show transitional relationship with the braided river deposits.
Cross-Bedding With Tidal Bundles and Mud Drapes: Evidence for Tidal Influence in Bhuj Sandstone (Lower Cretaceous), Eastern Kachchh
Authors: Singh Poornendu P. , Singh Indra Bir 
Published: November 2024

Abstract
Silty sandstone beds in Bhuj Formation show predominantly large-scale cross-bedding showing herring-bone structure with rippled interbeds. A well-preserved large-scale cross-bedded unit shows distinct bundle structures which are interpreted as Lidal bundles. These tidal bundles are arranged in thin bundles of neap and thick bundles of spring cycle of a tidal rhythm. Bundle boundaries of neap cycle often show doublemud drapes. Presence of tidal bundles, double mud drapes, and neap-spring cycle within a single cross-bedded unit indicate significant role of tides during deposition of Bhuj Sandstone, and points to a tide-dominated coastal area as a site of deposition for Bhuj Sandstone.
The Genus Hantkenina from Baratang Island, Andaman, India
Authors: Rajshekhar C. 
Published: November 2024

Abstract
The paper records the planktonic foraminiferal genus Hantkenina Cushman from Baratang Island, Andaman. The specimens of Hantkenina were recovered from the clayey sediments ejected from mud vo1canoes. Besides the genus Hantkenina, the clay material also yielded abundant and mixed assemblage of foraminifera ranging in age from Late Cretaceous to Eocene. The present finding of the genus Hantkenina suggests the presence of Late Eocene subsurface sediments on Baratang Island.
A Note on Incipient Spilitisation of Central Indian Basin Basalts
Authors: Karisiddaiah S. M. , Iyer S. D. 
Published: November 2024

Abstract
Rocks dredged in the vicinity of the 79°E fracture zone, in the Central Indian Basin, are sub-alkaline basalts, which are regarded as precursors to spilites. The Minerals identified are mainly albitic plagioclase, augite, olivine, and less of chlorite, epidote and opaques. The oxide variation plots indicate a mid-ocean ridge basalt trend for the samples, which have been spilitised to varying degrees. It is suggested that the basalts formed as a result of a fissure type of eruption along the fracture zone. Subsequently, some of the basalts were spilitised probably due to hydrothermal solution, possibly the result of tectonic activity along the fracture zone.
Cauvery - Its Geological Past
Authors: Radhakrishna B. P. 
Published: November 2024

Abstract
Geomorphological studies reveal that the river Cauvery as we see it today is a composite river made in up of two distinct parts which have been brought together as the result of an upwarp across the flow in comparatively recent times. The effect of the upwarp has been the rejuvenation of the river leading to its diversion southwards and linking it up with another east flowing river at a lower elevation, through a series of narrow stepwise diversion channels.
A Numerical Simulation of the Gneiss-Charnockite Transformations in Southern India
Authors: Swamy V. , Anantha Iyer G. V. , Menon A. G. 
Published: November 2024

Abstract
This paper presents a numerical simulation of the well-documented, fluid-controlled Kabbal and Ponmudi type gneiss-charnockite transformations in southern India using a free energy minimization method. The computations have considered all the major solid phases and important fluid species in the rock - C-O-H and rock - C-O-H-N systems. Appropriate activity-composition relations for the solid solutions and equations of state for the fluids have been included in order to evaluate the mineral-fluid equilibria attending the incipient charnockite development in the gneisses. The C-O-H fluid speciation pattern in both the Kabbal and Ponmudi type systems indicates that CO2 and H2O make up the bulk of the fluid phase with CO, CH4 H2 and O2 as minor constituents. In the graphite-buffered Ponmudi-system, the abundance of CO, CH4 and H2 is orders of magnitude higher than that in the graphite-free Kabbal system. Simulation with C-O-H -N fluids of varying composition demonstrates the complementary role of CO2 and N2 as rather inert dilutants of H2O in the fluid phase. The simulation, carried out on available whole-rock data, has demonstrated the dependence of the transfonnation X(H2O) on P, T, and phase and chemical composition of the precursor gneiss.
Initiation of Ptygmatic Folding in a Competent Siliceous Layer: An Experimental Study
Authors: Gairola V. K. 
Published: November 2024

Abstract
An experiment was carried out to develop ptygmatic fold in a competent agate layer embedded in an incompetent marble matrix in a triaxial press at a temperature of 650°C. The layer was deformed up to 21 per cent bulk-shortening under an initial confining-stress of 1 kb and at a strain rate of 7.95 x 10-7sec-1. The deformed layer exhibits the initial stages of ptygmatic folding. The stress-strain and time-strain relationships have been discussed. Thin-section study of the deformed layer reveals that recrystallisation of cryptocrystalline silica was the dominant mechanism of deformation. The low confining pressure and high strain rate was responsible for the development of tension and shear fractures in the agate layer.
Fallibility of Palaeo-Channels as Groundwater Potential Zones in a Part of Thar Desert
Authors: Tiwari O. N. 
Published: November 2024

Abstract
Integrated analysis of field data indicates that the Thar desert had a longer network of drainage in the past. Saraswati had been one of the major rivers. Aerial photointerpretation has been useful in definite identification of Kantli palaeo-channels in areas adjacent to the Aravalli hills. Signatures of palaeo-channels on space imagery are sometimes misleading as similar reflections are recorded from dunal depressions also and, hence. must not be thought of as indicating groundwater potential zones.
Characterization of Extractable Uranium in Domiasiat Sandstones, West Khasi Hills District, Meghalaya
Authors: Shivananda S. R. , Dwivedy K. K. , Kaul Ravi 
Published: November 2024

Abstract
Uranium mineralisation in Domiasiat sandstone is due to migration and fixation by biogenic processes, and leaching and redistribution by surface and groundwater. Fine-sized pitchblende and coffinite are associated with carbonaceous matter and pyrite. Characterization of the extractable uranium indicates that its nature varies from sample to sample and appears to be dependent on pH, Eh and the amount of soluble sulphates in them and to some extent on gangue minerals like calcite which can neutralise the acid component. It is inferred that alteration of sulphides and formation of sulphates results in an acidic condition favouring mobilisation.