bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tectono-Stratigraphy and Emplacement History of the Ophiolite Assemblage from the Naga Hills and Andaman Island-Arc, India
Authors: Acharyya S. K. , Ray K. K. , Roy D. K. 
Published: November 2024

Abstract
The oceanic pelagic sediments from the ophiolite assemblages of Naga Hills (NHO) and Andaman islands (ANO) broadly correspond to Late Cretaneous to Paleocene age. Late Cretaceous ocean floor represented in ANO was dominantly below the carbonate-compensation-depth (CCD), whereas it was uneven but mainly above CCD during Paleocene-Early Eocene. Maestrichtian to Paleocene ocean floor appears to be dominantly above the CCD in NHO. The NHO and ANO have closely similar postemplacement ophiolite-derived mid- and mid-late Eocene cover sediments respectively. Emplacement of the Naga Hills ophiolites during mid-Eocene, was possibly caused due to initial collision of an ocean-island chain with the subduction zone beneath the Central Burmese continent. Emplacement of the Andaman ophiolites occurred during early-mid-Eocene and may have been caused by a similar situation. The Chin Hills ophiolites were also mainly emplaced during early Eocene. The accreted ophiolites of the Indo-Burman range and Andaman islands were thrust westward over the Paleogene turbidite pile, deposited on the down going Indian plate during late Oligocene, due to terminal India-Burma continent-continent collision. In the southern Manipur sector of Naga Hills, the olistostromal upper Disang Formation (mid to late mid-Eocene) tectonically flooring the NHO, stratigraphically underlies the flyschoid to molassic Barail (Oligocene) sediments. In Andaman islands, the Lipa Formation with early Eocene and older olistoliths, forms the dominant constituent of the lower tectonic sedimentary melange flooring the ophiolites. Towards west, the sedimentary melange overrides the Archipelago Group. (Neogene) which unconformably overlies the Andarnan Flysch of Eocene-Oligocene age. The root-zone of the collisional suture appears to be concealed below younger sediments in the Central Burma basin and in the Andaman Sea, parts of the latter being created as a back-arc marginal basin. There is thus no straightforward relation between the Late Oligocene collision suture and the present subduction zone along the trench to the west of Andaman-Nicobar islands.
Geochemical Characteristics of Mudbank Environment - A Case Study from Quilandy, West Coast of India
Authors: Ramachandran K. K. 
Published: November 2024

Abstract
Aerial variatron of SiO2, Al2O3, MgO, CaO, TiO2, K2O and Na2O in the Mudbank sediments off Quilandy are discussed. A comparative study of textural classes versus the elemental concentration revealed a size dependence factor on the elemental speciation. Chemical variability depicted from cluster analysis suggests three interrelated elemental groups, such as (I) Al2O3, Fe2O3, Na2O and MgO probably controlled by hydrous aluminosilicates in the finer fractions, (2) TiO2, CaO and SiO2 with coarser materials especially CaO with shell fragments, (3) lone element K2O influenced by both hydrous aluminosilicates and feldspars.
Mudbanks are conspicuous with high load suspension. Initial triggering which brought the sediments into suspension is explained in terms of convulsive physical action during the onset of southwest monsoon. It has been found that mudbank sediments are enriched with alumina and ferric oxide. Salinity reduction in the nearshore waters due to monsoonal precipitation is an ideal condition (optimum electrolitic concentration) to defloculate and disperse the sediments into suspension in the presence of phosphate as a natural peptizer. Hence apart from the physical mechanism of suspension, dispersion as a chemical mechanism for the sustenance of suspension is suggested.
How old are the Old Mine Workings of Ingaldhal (Karnataka) ?
Authors: Shankar R. 
Published: November 2024

Abstract
Two 14C dates (2070 ± 110 years B.P. and 1820 ± 100 years B.P.) on wooden logs which were used as supports in old workings of lngaldhal copper mines are reported here. These dates are discussed in a historical/archaeological perspective.
On Applying the Concept of Rupture Propagation to Deduce the Location of the 1905 Kangra Earthquake Epicentre
Authors: Chander Ramesh 
Published: November 2024

Abstract
Richter estimated from analyses of P arrival times on available seismograms that the epicentre of the 1905 Kangra earthquake lay on the border of Jammu-Kashmir and Himachal Pradesh, approximately 100krn north of Kangra. This point lies far outside the limits of rupture deduced from analyses of macroseismic effects of the earthquake. We apply the concept of rupture propagation to suggest that the Kangra earthquake epicentre was in the southeastern part of the mcsoseismal area in the Chakraia-Mussoorie sector of the Lesser Himalaya near 31° N, 78° E.
On the Occurrence of Rugoglobigerina, Species in the Borehole (577M to 585 M) at Ambalapuzha, Alleppey District, Kerala
Authors: Rajendran C. P. 
Published: November 2024

Abstract
Planktonic foraminifera comparable to Rugoglobigerinarugosa encountered in the sediments occurring at a depth, ranging from 577 metres to 585 metres in a borehole at Ambalapuzha in the coastal district of Alleppey in Kerala is reported. Significance of these foraminifera present in the bottom most part of the onshore sedimentary basin of Kerala is briefly discussed.
Stromatolites from the Chert-Dolomites of Archaean Shimoga Schist Belt, Dharwar Craton, India
Authors: Vasudev V. N. , Naqvi S. M. , Shukla M. , Uday Raj B. 
Published: November 2024

Abstract
Stromatolites of stratifera type showing development of pseudocolumnar structures occur both in chert as well as dolomites near the Kumsi Manganese Mines in the Shimoga schist belt. This report ot stromatolites in the Shimoga belt further confirms widespread biogenic activity prior to 2.6 Ga in the Dharwar Craton.
A Study on Heavy Mineral Sands of Gopalpur Beach, Orissa
Authors: Patro B. C. , Sahu B. K. , Guru S. 
Published: November 2024

Abstract
Mechanical disintegration of source rocks and selective transport of resulting particles together generate log normally distributed traction, saltation, and suspension sand sub-populations of heavy minerals, ilmenite, zircon, rutile and sillimanite as for quartz. Plots of cumulative weight per cent frequencies in geometric size grades of these heavy mineral sand populations against an arithmetic size grade scale (mm. grade scale with equal class interval) on an arithmetic probability paper gives rise to a more sharply segmented curve than a plot of these frequencies against Ø scale and hence may be more effective in environmental discrimination. Wadell's shape factor is shown to give satisfactory results in the estimation of equivalent hydraulic sizes of the above heavy minerals from the associated quartz sands in a saltation population. The reported hydraulic inequrvalcncy observed in the case of coarser sand grades of heavy minerals with respect to those of quartz is explained to be due to restricted availability of these sizes rather than to differenual entrainment.
Growth Rate and Chemical Composition of a Manganese Nodule from the EEZ of Seychelles
Authors: Banakar V. K. , Borole D. V. 
Published: November 2024

Abstract
A ferro- manganese nodule collected in EEZ of Seychelles yields a growth rate of 1.5 mm/106Y by 230Th (ex) and 230Th (ex)/232Th activity ratio methods indicating very slow growth of ferro-manganese nodules. The Mn/Fe and U/Th ratios suggest that the genesis of the studied nodule is of hydrogenetic origin.
Stratigraphic Distribution of Ichnotaxa in Wagad Region, Kutch, India
Authors: Kulkarni K. G. , Ghare M. A. 
Published: November 2024

Abstract
Ichnofacies of rocks of Jurassic sequence of Wagad, Kutch, are identified on the basis of ichnoassemblages, Wagad Sandstone Formation belongs to shallow Cruziana facies; Washtawa Formation to deeper Cruziana facies; Gangta Member (East) to intermediate Cruziana facies and Gangta Member (West) to Zoophycos facies. The stratigraphic distribution of the ichnoasscmblages indicates regression of the sea from Argovian to Lower Cretaceous.
Small-Scale Structures in Tuffs Associated with Iron-Ore Volcanics of Barsua Valley, Sundargarh District, Orissa, India
Authors: Mohapatra B. K. , Paul A. K. , Sahoo R. K. 
Published: November 2024

Abstract
The paper records small-scale primary and secondary structures in different tuffaceous rocks of Barsua Valley, Sundargarh district, Orissa, India. The tuffs of acid, basic and intermediate composition are structurally both isotropic and anisotropic and form a part of the sheet-like tuff-tufflava-lava sequence of the Precambrian Iron-Ore Volcanics.
The primary bedding structures like tuff layers and laminations. cross-lamination and graded-bedding; secondary (deformational) structures like small-scale polyphase folds, their interference structures and associated boudins; distinctive structures, viz., small-scale faults etc. are described. Pre-tectonic soft sediment deformational structures are obscured by the imprint of tectonic structures.
Chemistry of Chromites from Boula-Nausahi Igneous Complex, Keonjhar District, Orissa and its Petrogenetic Significance
Authors: Mohanty J. K. , Sahoo R. K. 
Published: November 2024

Abstract
Chemical composition as well as different iomc ratios of chrome spinels of Beula-Nausahi ultramafic body, Orissa, have been determined. These data tell about the nature of original magma and temperature and oxygen fugacity of chromite crystallization. These data when compared with other well-known chromite deposits of the world, reveal a stratiform mode of origin for the deposit.
Organic Geochemistry of Oligocene-Miocene Deposits of the Bengal Foredeep, Bangladesh
Authors: Shamsuddin A. H. M. 
Published: November 2024

Abstract
The argillaceous rocks of Miocene age which are not rich in organic matter (TOC= 0.3-0.6%), contain predominantly humic type (terrestrial) organic matter (OM) with fair to moderate oil sourcepotential (H/C=0.7-Q.97) and. at an early stage of thermal maturation (R°=0.4-0.6%). are regarded as a possible source rock for gas/condensate accumulated in the nearby Bokabil and Bhuban sandstones. Oligocene sediments, on the other hand, are more rich in OM (TOC=O.7-1 .5%), contain predominantly mixed type of OM (humic-sapropelic) with good oil source potential (H/C= 1), are located at present within the oil window maturation limit (R°=0.65-1.2%) and are responsible mainly for oil generation in the region. The beginning of oil window has been traced at a depth between 3.6 to 5.0 km and at a temperature between 104° to 140°C. The great depth and high temperature at the beginning of the oil window are caused by low geothermal gradient and shortage of geological time. The study of deep catagenetic zonation of OM of rocks with relation to vertical zonality of hydrocarbon formation has enabled distinguishing three hydrocarbon generation zones in the sedimentary cover of the Bengal Foredeep:
(i) the upper catagenetic zone of gas generation (R°=0.4-0.6%);
(ii) the middle catagenetic zone of oil generation (R°=0.6-1.15%); and
(iii) the lower catagenetic zone of gas generation (R° &gt;1.15%).
The quantitative measurement of liquid and gaseous hydrocarbon based on material balance method suggests that the Oligocene-Miocene shales arc capable of generating enough hydrocarbon for commercial accumulation not only for gas, but also for oil.
Mining in Jharia Coalfield, Eastern India: An Estimation of its Impact Index
Authors: Ghosh Rekha 
Published: November 2024

Abstract
The Jharia Coalfield. throughout its past mmmg history, never had any well- thought-out regional master plan for mining, or any plans of environmental reclamation/ protection. As a result, the environment of this mining area is damaged by various undesirable impacts of mining, a major part of which was caused before nationalisation of coal mining industry in India. Some such impacts on land use and related features caused by mining and associated activities have been analysed and the overall impact index has been calculated through preparation of an impact matrix. The impact index, thus calculated through impact matrix, is considerably high and of a nagative value. The adoption of a land-use management plan is urgently needed.
Kink-Band Development in the Pukhri Slates of Chamba Syncline, Himachal Pradesh
Authors: Bhola A. M. , Lazarus D. V. 
Published: November 2024

Abstract
The geometry, angular relationship and strain in kink-bands developed on earliest fabric, S1, in slate/phyllite sequence of Chamba area, are studied. The field study substantiatcd by microscopic study reveals that gliding is not the only mechanism for their development, instead, more significant has been the dilation and rotation as suggested by the presence of parted larninae-dilatant zones having quartz filling in many kink-bands. Shearing along kink-band boundaries also played a role in the later stages of kink-band development.
Isotopic Variations in Limestones from Kurnool Sediments in Cuddapah Basin, India
Authors: Rao Dasari M. 
Published: November 2024

Abstract
The Kurnool Sediments (Upper Proterozoic), have been isotopically examined for the identification of carbonate isotopic signatures that might indicate subaerial diagenesis. The sequence contains limestones at two stratigraphic levels. The Narji Limestones are in the first cycle and the Koilkuntla limestones in the second cycle of deposition. The dO18 values for Narji limestones show a progressive increase from the basal to top horizons. The gradation in the dO18 value might be due to interaction of various horizons with fresh water in the later geological periods and possible consequent exchange. The dC13 values of the Narji Limestones lie within the range of marine limestones. The dO18 values for Koilkuntla limestones, are lower compared to the values of Narji limestones. This might possibly be due to greater interaction with fresh water and exchange during diagenesis.
Fluoride Incidence in Natural Waters in Amreli District, Gujarat
Authors: Sahu N. K. , Karim M. A. 
Published: November 2024

Abstract
Leachable fluoride absorbed in the soil and clays are the main sources of fluoride in groundwater. A good correlation between F- and Na+ (lithogenic sodium) have been obtained. Alkalinity of the circulating waters may be one of the deciding factors for the high incidence of fluoride in natural waters in Amreli district.
Geophysical Signatures of Kuilapal Granite, Singhbhum, India and their Significance
Authors: Narasimha Rao R. L. , Anantharaman K. B. 
Published: November 2024

Abstract
Granites having large depth extent indicated by negative Bouguer gravity anomalies are sought for, because they playa crucial role in the formation of uranium provinces by mobilising the radioelements from mantle or deeper parts of crust by hydrothermal convection generated as a result of radioactiv e decay in the pluton. The Bouguer gravity data reveals that the Kuilapal granite has a large depth extent, extending to 20 km into the crust and the margins of this granitoid are distinguished by doughnutshaped magnetic features intimately associated with radiometric anomalies. Such geophysical signatures arc interpreted to qualify this granite as 'mineralised'.
Discovery of Redlichid Trilobites from the Arenaceous Member of the Tal Formation, Garhwal Syncline, Lesser Himalaya, India
Authors: Joshi Ashutosh , Mathur V. K. , Bhatt D. K. 
Published: November 2024

Abstract
The paper records the first find of identifiable redlichid trilobites, belonging to two genera, from the strata of the Arenaceous Member of the Tal Formation in the Garhwal Syncline. This fossil horizon in the Garhwal Syncline, in the past, has also yielded small shelly fossils. The chronostratigraphic designation of this small shelly fauna in the Qiongzhusian (? Atdabanian) Stage of China now stands corrected with the present discovery. The trilobite genera correspond to the Botomian Stage (1 Tsanglangpuian Stage of China), in the Early Cambrian.
Late Miocene to Early Pliocene Radiolarian Biostratigraphy of Neill Island, Andaman Sea
Authors: Sharma V. , Sharma G. K. 
Published: November 2024

Abstract
104 species of radiolaria are recorded from a Late Miocene-Early Pliocene sequence exposed at Neill Island. The assemblage shows presence of a few reworked radiolarian species. The radiolarian zones proposed for low latitude areas are applicable in the present study. Two zones, viz., Didymocyrtis penultima Zone and Stichocorys peregrilla Zone, have been recognized in the sequence. Based on the study of pianktonic foraminifera of the same sequence by earlier workers, an integrated scheme of radiolarian and foraminiferal zones is presented.
Early Permian Plant Microfossils from the Intertrappean Beds of Abor Volcanics, Arunachal Pradesh, India
Authors: Prasad Bijai , Dey A. K. , Gogoi P. K. , Maithani A. K. 
Published: November 2024

Abstract
Selected samples from the intertrappean beds of Abor Volcanics were macerated for palynofossils in an attempt to provide fossil evidence for their age, The palyno-fossils so far isolated are trilete and monolete microspores, radial monosaccates and striated as well as non-striated disaccate pollen of Early Permian age. The fossil evi dence suggests similar age to the intertrappean beds and lead to the conclusion that the Abor Volcanics of the studied area viz., Yinkiong, Dalbuing and Mariyong of Dihang valley (Arunachal Pradesh) are of Early Permian age.
Late Proterozoic-Early Palaeozoic Rb-Sr Whole-rock and Mineral Ages for Granite and Pegmatite, Goalpara, Assam, India
Authors: Van Breemen O. , Bowes D. R. , Bhattacharjee C. C. , Chowdhary P. K. 
Published: November 2024

Abstract
A granite that cuts the basement gneiss complex yields a five point errorchron giving an age of 647 ± 122 Ma. Uniform Rb-Sr isotopic ratios on the scale of a small quarry (c. 20 m) permit calculation of a maximum age of 850 Ma. Muscovite books from a second of three sets of pegmatite veins to cut the granite yield an Rb-Sr age of 505 ± 5 Ma. Both whole-rock and mineral age data are interpreted as representing times of crystallization and are in the time range of Pan-African activity known from, other fragments of Gondwanaland.
Marine Geophysical Studies off Karwar, West Coast of India
Authors: Subrahmanyam V. , Ramana M. V. , Subba Raju L. V. 
Published: November 2024

Abstract
Geophysical studies of the southwestern continental margin revealed significant surface and subsurface topographic highs (ridges) trending NNW-SSE to NW-SE beyond the shelf break. Residual magnetic anomaly map depicts prominent NNW-SSE, NW-SE and E-W trends. The magnetic anomaly map also reveals three different provinces, A, B and C, based on magnetic signatures, confined to inner shelf, outer shelf and lower shelf. A prominent E-W trending structural Jineament with a NW-SE trending offset is observed cutting across the inner shelf and the lower shelf. Model studies of the geopotential data over the topographic rise indicate about 18 km thick mafic basement of continental origin at a shallow depth (∼800 m). The gravity model studies indicate a thick consolidated sediment layer deposited over the horst and grabenlike features within the granitic layer. The occurrence of ridges parallel to the shelf edge shows the similarity of the western Indian continental margin with the other typical and extensively studied passive margins.
Idukki Earthquake and the Associated Tectonics from Gravity Study
Authors: Mishra D. C. , Singh A. P. , Vyaghreswara Rao M. B. S. 
Published: November 2024

Abstract
The Idukki earthquake with epicentre around Nedumkandam, approximately 20 km east of the Tdukki reservoir, has been in the news. A detailed gravity profile from Bangalore to Trivandrum across Cardamom-Palni hill ranges has delineated a fault type of anomaly coinciding with the epicentre of the earthquake whose modeHing suggests a shallow fault extending up to 10-11 km. This feature being associated with a thick crust in this region controlled by deep faults might have got reactivated to cause this earthquake.
Palynological Evidence for the Presence of Upper Permian Sediments in the Northern Part of Rajmahal Basin, Bihar
Authors: Tripathi Archana 
Published: November 2024

Abstract
Palynological analysis of Bore hole RJNE-8 and RJNE-16 (drilled in the northern part of the basin) reveals presence of an assemblage which is correlatable with palynoflora of Upper Raniganj age. Appearance of elements, like Lundbladispora, Densoisporites, Lunatisporites, Goubinispora and Pretricoipipollenites indicates closing phase of Late Permian palynoflora. These results extend the presence of Upper Permian sediments up to south of village Barahat (Bara) along Godda Pirpainti Road in Rajmahal Basin.
Structural Relations of Proterozoic Cover and Its Basement: An Example from the Jahazpur Belt, Rajasthan
Authors: Sinha-Roy S. , Malhotra G. 
Published: November 2024

Abstract
In the Jahazpur belt of SE Rajasthan, the Proterozoic Jahazpur cover sequence of dolomite, BIF, orthoquartzite and tuffaceous carbonaceous phyllite unconformably overlies the Archaean basement comprising granite-greenstone sequences of the Hindolis and the Mangalwar Complex. The Jahazpur rocks developed in ensialic aborted rifts. Structures of four deformations in the basement rocks and of three deformations in the cover rocks have been recognised, the first deformation of the basement rocks being pre-Jahazpur in timing. The first and the second regional folds in the Jahazpur sequence have produced type-2 interference pattern. The original orientation of the first fold was almost E-W. The second fold, trending NE-SW, reoriented the first deformation structures, and controlled the linear trend of the belt. The unconformity between the cover and the basement has been modified by thrusting.
First Record of Ediacaran Fossils from the Krol Formation of Naini Tal Syncline
Authors: Mathur V. K. , Shanker Ravi 
Published: November 2024

Abstract
The paper records the discovery of Ediacaran fossils, viz., Beltaneliformis sp. cf. B. brunsae Menner, Pteridinium sp. cf. P. simplex Gurich and Ichnogenus Gordia sp. cf. G. marina Emmons from the upper part of the Krol Formation in the Naini Tal Syncline, Lesser Himalaya. These taxa are comparable with the fossils present in the late Precambrian Wernecke assemblage of Canada and Ediacaran assemblage of other areas, particularly Australia and Eurasia.
Fossil Decapod Crustacea from Upper Sylhet (Prang) Limestone of Jaintia Hills, Meghalaya
Authors: Satsangi P. P. , Changkakoti U. N. 
Published: November 2024

Abstract
A new species of decapod crustacea, Palaeocarpilius bispinosus, is described from the Middle Eocene Upper Sylhet (Prang) Limestone of Jaintia Hills, Meghalaya. This is the first report of the genus from North Eastern India.
Fair-Weather versus Storm Beach: An Example from The Goa Coast
Authors: Chakraborty Chandan 
Published: November 2024

Abstract
The Goa coast of southern India is affected by short-term storm events during summer which perturb the fair-weather beach equilibrium considerably. The storm surge ebb at Goa coast moves perpendicular to the shoreline and deposits its load in the form of shore-parallel ridges. Renewal of fair-weather condition throws the storm profile into disequilibrium and exposes part of the storm-induced ridge field. The effort for re-equilibration establishes a new beach profile in which the part of the storm-induced ridge field turns into backshore.
Effect of Sediment-Water Interface 'Boundary Layer' on Exposure of Nodules and Their Abundance: A Study from Seabed Photos
Authors: Sharma Rahul 
Published: November 2024

Abstract
The results obtained from seabed photos and boomerang grab samples reveal a striking similarity in distribution patterns of size classes of polymetallic nodules. Due to partial sediment cover, there is a 'fractionation' effect on nodules, which affects nodule abundance estimates based on photos. A model showing variable burial (or exposure) depending upon the thickness of the Sediment-Water Interface Boundary (SWIB) layer is presented. Standard relationships can be established between nodule burial and SWIB thickness.