bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palaeoenvironmental Reconstruction of the Early Proterozoic Kolhan Siliciclastic Rocks, Keonjhar District, Orissa, India
Authors: Ghosh Sumit K. , Chatterjee B. K. 
Published: November 2024

Abstract
The early Proterozoic Kolhan sihciclastrc rocks of the Kolhan Group (c. 2100 Ma) exhibit extensive-development of thickly bedded sandstone, impersistent conglomerate and siltstone. Six major lithofacies were recognised, viz, granular lag (GLA), granular sandstone (GSD), sheet sandstone (SSD). parallel laminated sandstone (PLSD), rippled sandstone (RSD) and thinly laminated siltstone-sandstone (TLSD). The vertical and lateral arrangement of lithofacies with their general finmg upward sequence is interpreted to reflect superimposition of retrograding shoreline on the earlier, prograding humid alluvial fan-sandflat complex and can be comparable with the present day storm-induced sedimentation on the NW Atlantic shelf.
The Podili Syenites - A Suite of Alkaline and Subalkaline Rocks from Andhra Pradesh
Authors: Madhavan V. , Sugrive Reddy A. G. 
Published: November 2024

Abstract
The alkali syenites of Podili represent a mildly undersaturated nepheline nonnative microsyenites (NNMS) and quartz nonnative microsyenites (QNMS). All the microsyenites have developed nonnative acmite and are totally free from normative hypersthene. In contrast, the quartz syenites always carry normative hypersthene and are invariably devoid of normative acmite.
In the variation diagrams. the PodiIi syenites form distinct petrochemical trends indicating their consanguineous relationship. A dichotomous differentiation trend is discernible.
Some Observations on the Phosphatic Rocks of the Lower Gondwana Sequences of the Ib River Coal Field, Sundergarh District, Orissa, India
Authors: Raha Pulak Kumar 
Published: November 2024

Abstract
The phosphate occurs as discontinuous patches forming massive compact claystone-like rocks. Submicroscopic grains of quartz, feldspar and flakes of mica, and grains of cryptocrystalline rock fragments and chert occur in a phosphatised ground mass. Coarsely crystalline calcite and siderite of secondary origin are commonly associated. The cores of nodular masses show altered. olivine, pyroxene, prismatic calcic plagioclase, rock and chert fragments, and vein-quartz in a coarsely crystalline carbonate cement, while the outer shells of the nodular bodies are of amorphous phosphatic material. Trace-element analyses show high values of Ba, Y, and La in phosphatic rocks compared to non-phosphatic ones. An igneous source for the clasts in the cores of nodular bodies and secondary phosphatisation through late hydrothermal solutions are suggested.
Submarine Debris-Flow Deposits from the Ordovician Mane Ting Formation in Tethyan Black Mountain Basin, Central Bhutan
Authors: Bandyopadhyay B. K. , Gupta Anupendu 
Published: November 2024

Abstract
The rocks in the basin range in age from Early Ordovician to Devonian. Proximal sedimentation began with the deposition of an orthoquartzite-conglomerate lithofacies of the Nake Chu Formation. Rapid sedimentation coupled with quicker subsidence initiated a period of instability that led to the deposition of the distal facies sediments of the Mane Ting Formation characterised essentially by interbanded quartz wacke and shale with an input of andesite. A number of conformable interbedded para-conglomerate beds, identified as submarine debris flow deposits, occur within this Mane Ting Formation.
Lithic fragments ranging in size from 1 mm to 2 m and upwards constitute one modal class and are of diverse types, including quartz wacke, shale, quartzite and chert and limonitised clasts. Monocrystalline quartz, muscovite, siderite and feldspar in combination with the matrix define the second mode with size ranging from 1/4 to l/200 mm. The bimodality is interpreted to be due to mixing of the coarse sand and gravel component with the matrix.
Intact load structures and convolute folds in rip-up clasts and rafts, very poor sorting with high mud matrix, angularity of the constituent fragments. chaotic and often vertical orientation of the platy clasts and the presence of mud balls, armoured sand grains and shale-coated clasts strongly suggest transportation within a high density, cohesive debris-flow.
Pre-Monsoon Living Planktonic Foraminifera from the Southeastern Arabian Sea
Authors: Guptha M. V. S. , Divakar Naidu P. , Muralinath A. S. 
Published: November 2024

Abstract
Examination of 39 vertical zooplankton hauls from the southeastern Arabian Sea for living planktonic foraminifera showed the presence of 28 species indicating highest diversity during summer of the year 1985. The maximum recorded abundance off Cape Comorin was 3100/1000 m3. while the highest abundance of 1320 specimensl 1000m3was encountered off the coast of Kerala.
Based on the planktonic foraminifera, two assemblages of summer tropical Arabian Sea and summer Arabian Sea upwelling were encountered off Kerala coast and south of Cape Comorin respectively. Foraminiferal diversity observed was quite high in this region. The standing crop of planktonic foraminifera encountered was highest off Cape Comorin coast.
Ore Mineralogy and Fluid Inclusion Characteristics of Different Ore Associations from Malanjkband Copper Deposit, M. P. (India)
Authors: Panigrahi M. K. , Mishra B. , Mookherjee A. 
Published: November 2024

Abstract
Textural and paragenetic study of primary minerals (chalcopyrite, pyrite, magnetite, hematite, sphalerite, bornite, chalcocite and molybdenite) reveal intermittent fracturing, precipitation and dissolution phenomena with at least two recognizable stages: magnetite(I) - pyritc(I) - molybdenite (?) followed by pyrite(II) - chalcopyrite - sphalerite - magnetite(II) - hematite - bornite - chalcocite. Oxidation and supergene enrichment effects producing cuprite-malachite-native copper and chalcocite-covellite are moderate. Difference in the mineralogy of the oxidation zone and restricted occurrence of supergene enrichment are due to the variation in the primaty mineralogy of the ore.
The ranges of fluid inclusion homogenization temperature (maxima 160°-180°C) and fluid densities in the reef quartz and ore bearing vein quartz are more or less the same, with a wider range of salinity in the vein quartz ores. However, mixed aqueous carbonic inclusions are restricted to the vein quartz ores and hence points towards a difference in the fluid regime. Th vs. salinity and Th vs. density plottings rule out simple cooling and/or mixing processes in the evolution of the fluid but rather hint at immiscible two-fluid phase separation. The suspected presence of low temperature Iss-phases and the results of fluid inclusion microthermometty point towards an unexpectedly low temperature environment of ore deposition. The paragenetic sequence is suggestive of an increase in the Cuffe ratio and fluctuating fO2 conditions in the fluid during the main stage of mineralization.
Magnetic Anomalies and Basement Structure Around Vizianagaram, Andhra Pradesh
Authors: Radhakrishna Murthy I. V. , Polinaidu B. , Rao A. T. 
Published: November 2024

Abstract
Magnetic anomalies in an area of about 1500 sq km around Vizianagaram town in Andhra Pradesh bring out a shallow magnetic basement of charnockitic rocks, which is highly faulted. The magnetic basement exhibits horst and graben-like structures and broadly maintains conformable relations with the antiformal and synformal structures of the overlying khondalite suite of rocks. The development of these faults is attributed to the earlier folding of the Eastern Ghats and their refolding about a N-S axis to change their initial NE-SW trend to E-W and NW-SE in the nonhern part of Andhra Pradesh. The development of the horst-graben type structure is explained by movements of the faulted blocks along the fault planes at different stages or tectonic activity.
Locomotory Traces (Repichnia) from the Jurassic sequence of Kutch, Gujarat
Authors: Kulkarni K. G. , Ghare M. A. 
Published: November 2024

Abstract
Of the seventeen ichnoforms, many are dominantly associated either with fodinichnia or pascichnia. Such an association, suggests low to moderate energy conditions and shallow water environment of deposition. Replacement of Curvolithus by Gyrochorte reflect minor oscillations in sea-level. Facies variations are decipbered by studying percentage distribution of repichnia in relation to other ethological groups.
Pleistocene Benthic Foraminifera and DeepM
Authors: Gupta Anil K. 
Published: November 2024

Abstract
The evolution of Pleistocene deep-sea environments at Northern Indian Ocean DSDP Site 219 has been evaluated, using the quantitative analyses of deep-sea benthic foraminiferal fauna. The Pleistocene assemblages are dominated by Uvigerina proboscidea which shows remarkable frequency changes. The relative abundances of characteristic benthic foraminifera, and patterns of Species Diversity and Equitability have enabled identification of four events (C1-C4) of major faunal turnovers. These events have been inferred to represent intervals of fundamental changes in atmospheric oceanic circulation, most likely the cooling and intensification of bottom-waters due to major increase in polar ice volume.
Tectono-Stratigraphic Framework and Volcanic Geology of the South Delhi Fold Belt in Central Rajasthan
Authors: Gupta P. , Mukhopadhyay K. , Fareeduddin  , Reddy M. S. 
Published: November 2024

Abstract
The Delhi rocks are deposited in two sub-basins separated by a median inlier of Pre Delhi rocks. The Barotiya and Sendra Fonnations occupying the western sub-basin contain significant basic flows and tuffs with associated felsic volcanics. The eastern sub-basin recording a diachronous evolutionary history is the repository of the Rajgarh and Bhim sediments.
Striking similarities are noted in respect of lithology, structure and metamorphism amongst the gneisses and schists of the Pre-Delhi rocks flanking the Delhi Supergroup and also of the median inlier. Structural imprints and contact relationship indicate that these gneisses and schists fonn the basement for the Delhi sediments. Migmatization related to orogeny suggests reactivation of a sialic basement, which along with the tectonic emplacement of basement slices in the Delhi stratigraphy argue in favour of an intra-cratonic development of the Delhi basin.
The western sub-basin shows bimodal volcanism and the various geochemical discriminants suggest an IATor MORB setting, but fail to make a choice between the two. Bimodal volcanism in association with shallow clastic sediments signify ensialic origin in a rifted mobile belt. Structural studies indicate large-scale dextral vergence with steep 'S' surfaces which are characteristic of oblique shear transpressive mobile belt.
Fluid Inclusion Studies in Apatite of the Sung Valley Carbonatite Complex, N. E. India: Evidence of Melt-Fluid Immiscibility
Authors: Jaireth S. , Sen A. K. , Varma O. P. 
Published: November 2024

Abstract
The Sung Valley carbonatite complex of Cretaceous age has a core of serpentinized peridotite rimmed by pyroxenite. The complex is intruded by small- to medium-sized bodies of uncompahgrite, ijolite, syenite and carbonatite. The carbonatites occur as stocks, lenses, dykes and veins. Apatite grains in the apatite-magnetite sovite are characterized by three varieties of apparently syngenetic primary inclusions: The type S (solidified) inclusions contain highly birefringent and anisotropic solids along with some gas and liquid; the co-existing type F (fluid) inclusions are of two types-low to moderate salinity gas-liquid inclusions (gas= 15 to 35% by volume) and high salinity gas-liquid inclusions with one or more daughter minerals (halite, sylvite, carbonates). Type S inclusions homogenize into a relatively viscous, melt-like liquid at temperatures between 740 and 806°C whereas type F inclusions homogenize into a liquid phase at temperatures between 177 and 488°C. The large variation in homogenization temperatures between type S and type F inclusions and the difference in their composition are interpreted to be the result of a liquid immiscibility between a volatilerich carbonate melt and a saline aqueous fluid, though contribution of necking down of some original inclusions in generating clusters of type S and type F inclusions cannot be ruled out completely.
Geology, Petrography and Systematic Stratigraphy of Pre-Ariyalur Sequence in Tiruchirapaui District, Tamil Nadu, India
Authors: Ramasamy S. , Banerji Ranjit K. 
Published: November 2024

Abstract
A new litho unit-Terani Formation is proposed. The lower part of the Uttatur Formation is found to be homotaxially equivalent to the Dalmiapuram Formation. A new geological map based on these units is presented.
Evaluation of Deformational and Depositional Controls on Pebble Characters - A Study of Bisrampur Conglomerate, Singhbhum, Bihar
Authors: Ghosh Anirvan , Bose Mihir K. 
Published: November 2024

Abstract
The conglomerate horizon near Bisrampur in Singhbhum, Bihar, on the flank of Archaean (Singhbhum granite) platfonn, manifests a highly mature pebble assemblage in an argillaceous to arkosic matrix. The triaxial pebbles in conglomerate show readily recognizable down dip preferred orientation of longest axes and a common graving lineation on pebble surfaces. Strain analyses indicate a feeble relative dominance of flat type pebbles and a possible non-random orientation pattern of the primary deposited nonspherical pebbles. Calculation of finite strain also suggests that the axial parameters of pebbles cannot be related to a single phase of deformation. Thus, there may be two factors involved responsible for triaxiality of pebbles, one prior to deposition and a later modification by feeble deformation. Although spatially associated to a strongly tectonised domain to the north, the conglomerate largely retains the primary depositional character controlled by mass flow on the basin flank. This behaviour may be resolved by protective character of the channel filling on continental slope.
Constraints on the Evolution of the Purana Basins of Peninsular India
Authors: Kale Vivek S. 
Published: November 2024

Abstract
The seven supracrustal, epicratonic Purana basins occupy more than a fifth of the area of Precambrian exposures in the Indian Shield. They are repositories of Proterozoic shallow marine sediments, resting unconformably on the eroded surfaces of the older rocks; and are preserved in an unmetamorphosed and marginally deformed state. These sequences have comparable characters though their mutual differences are quite significant, indicating that each one of the host basins had an independent evolutionary history.
The gross sedimentological contents, associated igneous rocks, structural and metamorphic features of the Purana basins and their geographical and temporal proximity with the Middle Proterozoic Mobile Belt are examined to evaluate the broad geotectonic framework within which they evolved. These "polyhistory, continental" basins are apparently analogous to the "Atlantic-type" passive continental margin systems associated with extensional tectonic regimes. The Bhima basin is an exceptional case of a "simple", transtensional, "pull-apart" type basin, while some of the others were probably initiated as "back-arc" basins.
Geochemistry of the Tertiary Formation at Pozhikkara Cliff Section, Kerala-Its Palaeoenvironmental Significance
Authors: Seralathan P. , Padmalal D. 
Published: November 2024

Abstract
The Tertiary sequence begins with fossiliferous marl and is overlain by carbonaceous clay, china clay and laterite. The thin (3 cm thick), hard, compact duricrust layer, which is found interbedded within the carbonaceous clays, shows abnormal geochemical anomalies. Major elements such as Fe, Mn and Ca and the trace element Co show about 2-3 fold and 1-2 fold increase respectively in the duricrust than the upper and lower sections. However, the content of Na, K, Ni, Cu and organic carbon show an opposite trend. Cd does not show any marked variation along the profile. The CaCO3 content is remarkably high in the duricrust and marl than the other layers. Fe and Mn contents are much higher in the laterite than china clay, other parameters do not show much variation. The high content of Fe, Mn, Ca and CaCO3 and low Ni/Co ratio and organic carbon content in the duricrust layer indicate an oxidizing environmental condition which existed at the time of the formation of this layer, while the converse trend of these parameters in the carbonaceous clays indicate the prevalence of a reducing condition.
Geothermal and Rheological Implications of the Crustal Earthquakes Within and West of the Arakan-Yoma Fold Belt (Northeastern India)
Authors: Cermak V. , Bodri L. , Saikia M. M. 
Published: November 2024

Abstract
The study area, which represents a boundary collision zone between the Indian and Euroasian plates, has been the focus of intense seismic studies for decades. Except for events that have been clearly associated with the underthrusting of the Indian plate. the data reported by the regional network in the Northeastern Regions of India indicate a layer of concentrated seismicity in the lower crust at a depth range of 30 to 40 km. The lithosphere rheology was assessed on the basis of the frictional failure in the brittle regime, and power-law steady-state creep in the ductile regime. Rheological profiles were constructed fora 1-0 crustal structural and thermal model. The rheological stratification of the lithosphere was compared with the earthquake depth distribution which indicated a reasonable confinement of seismicity to brittle horizons.
Syn-Sedimentary and Later Remobilised Epithermal Pb-Zn Mineralisation of the Great Limestone, Riasi, J & K - Signatures in Fluid Inclusions and Stable Isotope Compositions
Authors: Nayak B. K. , Sharma Rajesh 
Published: November 2024

Abstract
A strong stratigraphic control is exhibited by the sporadic Pb-Zn occurrences in the Great Limestone of Riasi, J & K. Fluid inclusion thermometry and stable isotope data suggest their remobilisation and concentration in the fractures developed in the host-rock at the time of orogenic movements and the final deposition may be due to the mingling of at least two fluids; one epithermal; generated due to orogenesis and the other, meteoric water.
Crenulation Cleavage Development in Pukhri Formation of Chamba Area, Western Himachal Pradesh, India
Authors: Bhola A. M. 
Published: November 2024

Abstract
The geometric and tectonic significance of crenulation cleavage in Pukhri Formation (mainly pelitic sequence with interbedded thin quartzitic layers) of Chamba area, is studied by taking into account modifications taking place in original class 1-3 fold layers by three theoretical models viz. i) Homogeneous flattening ii) Shearing along the axial plane of folds iii) Volume reduction in multilayers. Theoretical model studies supported by the study of cleavage microstructure and microlithons in microfolds of Class 1-3 pairs point out that volume reduction model is most appropriate in explaining the development of crenulation cleavage, its intensity and frequency in the Chamba area.
Tectonic Strain Ratio Computed from the Mean Shape of the Ellipsoidal Passive Particles
Authors: Roday Prakash P. , Katpatal Yashwant B. 
Published: November 2024

Abstract
All methods of computing Rs. the tectonic strain ratio from the various means (of axial ratios of ellipsoidal particles that undergo deformation homogeneously with the matrix-the passive particles) such as arithmetic (̅Rf). geometric (Rg) or harmonic (H) fail to adequately express the real values of Rs. Using the data given by Lisle (1979) for simulated conglomerates, it is shown that ̅RfH = H+̅Rf÷2-(H+̅Rf)-1 is closest to Rs if Rs &gt; Ri. For Ri &gt; Rs (2φ &gt; 90° in a given principal plane), R' (given by ̅Rfa-̅Rfa-2/̅Rfb-̅Rfb-1 or by ̅Rfa-̅Rfa-1/̅Rfb-̅Rfb-2, depending upon whether Rib &gt; RSb or Ria &gt; RSa respectively) gives the value of k and the values of a and b that are closest to that of the superimposed Rs. The data are tabulated and also plotted on a conventional Flinn diagram.
A Mid Holocene Strandline Deposit on the Inner Shelf of Cochin, West Coast of India
Authors: Purna Chander Reddy N. , Durga Prasada Rao N. V. N. 
Published: November 2024

Abstract
Beach sediments with a phi mean size varying from 1.07 to 2.9 are well to moderately sorted and to a great extent negatively skewed. On the inner shelf, the sediments exhibit a wide range (0.9φ and 10φ) in mean grain-size. While most of the inner shelf is covered with fine silts and clays, sandy sediments occupy a linear belt in the outer parts (-25 to -30 m) of the shelf. These moderately sorted sands are considered to be relict and deposited during a standstill of the Holocene transgression. The CM pattern suggests that the sandy sediments in the inner shelf like the beach sands were deposited under high energy conditions. The well-preserved sands indicate that the existing hydrodynamic conditions on the inner shelf are neither strong enough to rework the sediments nor transport the modern river-contributed fine sediments to the outer parts.
A Mathematical Approach to the Petrogenesis of the Upper Siwalik Conglomerates (L. Pleistocene) of the Jammu Region, Northwest India
Authors: Mohan Chander , Gundu Rao C. 
Published: November 2024

Abstract
In sedimentary petrography, interpretation of the source and process from the response data i.e., characteristics of the deposited sediment is a convention. The best suited mathematical technique in such an exercise is 'Principal Component Analysis'. Applying this technique to the Upper Siwalik Conglomerates of Jammu region, northwest India (Lower Pleistocene, Cromerian) five components were extracted representing 68% of total variation in the conglomerate system. Components C1, C2 and C4 were identified with erosion and transporting processes (size, size sorting and shape), C3 with composition (quartzite and sandstone pebble proportions) and C5 with depositional processes (orientation and packing). Also, the analysis suggests that instead of three values of each of size and size sorting, and four values of shape used in the investigation, one measure of each of size, size sorting and shape is quite sufficient to explain the total variation in the petrographic properties of the Upper Siwalik Conglomerates of Jammu region.
Neotectonic Movements in the Loharkhet Area, District Almora, Kumann Fiimalaya
Authors: Pant P. D. , Goel O. P. , Joshi Mallickarjun 
Published: November 2024

Abstract
Thrusts, fold axes and fault zones in the Loharkhet area in the northern part of Almora district in Uttar Pradesh, record reactivation during Neogene times. Several alluvial and colluvial deposits in the area are being vertically and horizontally offset, and tilted by active folding and faulting. The recent movements along the Ravetiganga overturned anticline and Dulam Gadhera- and Vongarh-Gason-faults have not only uplifted the Nasati-Rithabagar block by about 103 m, but have shifted also the original confluence of the Sarju and Ravetiganga rivers by 11 km southwestward.
The ESE-flowing Gurkhula Gad and Mehar Gad streams have been deflected towards SSE direction by the recent strike-slip movements along the Kaphlikot-Ramari Fault. The Ramari landslides fan has been displaced vertically by 3 m along this fault. Terraced toe of the colluvial cone of the Badiyakot landslide has been displaced dextrally and uplifted by 18 m along the NNW-SSE striking Ghatia Gad Fauh.
The geomorphic expressions of the various tectonic zones indicate both vertical and strike-slip displacements. Rejuvenation of the earlier mature terrain is borne out by topographic changes that have taken place in the recent past. The topographic development indicates continuing uplift in some sections of Vaikrita (MC) Thrust and Berinag Thrust and the zone of the Ravetiganga overturned anticline. Relatively higher rate of uplift is observed for the MCT zone.