Department Of Geology

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Sharks and rays (chondrichthyes, elasmobranchii) from the miocene sediments of Kutch, Gujarat, India: paleoenvironmental and paleobiogeographic implications
(Taylor and Francis Ltd., 2021-03-05T00:00:00) Sharma, K Milankumar; Singh, N Amardas; Patnaik, Rajeev; Tiwari, R.P.; Singh, Ningthoujam Premjit; Singh, Y Priyananda; Choudhary, Deepak; Lalotra, Sushil Kumar
We report here a diverse assemblage of sharks and batoids representing the genera Carcharhinus, Rhizoprionodon, Galeocerdo, Sphyrna, Myliobatis, Aetobatus, Dasyatis, Pastinachus, Himantura and Pristis from Tapar and Jangadia the two late and early Miocene sites, respectively, of Kutch (Gujarat, India). The shark Rhizoprionodon and batoids, Dasyatis rugosa, D. cf. probsti, Dasyatis sp., Pastinachus and Himantura are being reported for the first time from the Miocene of western coast of India. The presence of Carcharhinus sp., Rhizoprionodon sp., Lamna sp., Negaprion sp., Sphyrna lewini, Myliobatis sp., Aetobatus sp. in the early Miocene Khari Nadi Formation exposed at Jangadia suggest existence of lagoonal, near shore to outer shelf environment. The rich batoid assemblage at the Late Miocene hominoid (Sivapithecus) bearing site of Tapar indicates the presence of a fresh to brackish water environmental condition. The faunal similarity of Miocene chondrichthyan of Indian Ocean and the Mediterranean Sea regions has been assessed using the beta diversity (S�rensen�Dice coefficient) data. The early Miocene elasmobranchs from Kutch shows close affinities with those from Mediterranean Sea. Similarly, in the Indian Ocean region Miocene fauna of Kutch shows close similarity with those of Baripada Beds, Orissa, Bhuban Formation of Mizoram, Gogha Coast, Piram Island and Madagascar. � 2021 Informa UK Limited, trading as Taylor & Francis Group.
Assessment of irrigational indices in surface water and shallow groundwater in the alluvial plain of Barak Valley, Assam, Northeast India
(John Wiley and Sons Ltd, 2021-06-25T00:00:00) Devi, Khangembam Sharmila; Singh, Kshetrimayum Krishnakanta
The main sources of water resources of the Barak Valley of Northeast India for irrigation are the surface water bodies in the form of ponds, lakes, rivers, and groundwater. This paper elucidates insight into the irrigational parameters to classify the types of water, based on these indices. Total hardness shows that 90% of surface water belongs to the soft and 63% of groundwater samples belong to the soft category. C-S plot shows 33% of surface water belongs to C1-S1 and 66% of groundwater samples belongs to C1-S1 and C2-S1, indicating fresh and suitable for use. The percentage Na+ shows most samples belong to good and permissible categories. Permeability index shows 81% of surface water in Class II and 18% in Class III, indicating good and bad types, respectively. Kelly's index suggests 90% of surface water is suitable and 9% is unsuitable, while 14% of piedmont groundwater is unsuitable. Magnesium hazard reveals 18% of surface water has more than 50 Magnesium absorptio ratio, leading to unsuitable, while 28% of piedmont and 33% of flood plain groundwater samples belong to unsuitable. Residual sodium carbon suggests surface water as suitable, while 48%, 12%, and 6% of groundwater belong to suitable, marginal, and unsuitable categories, respectively. Irrigation Water Quality Index values indicate that surface water is characterized by a highly restricted class, as they are exposed to surficial contamination as compared to groundwater. Base exchange index of ions indicates Na+-SO4?2 hydro-facies type suggesting dissolution of salt minerals in weak acidic water. Meteoric genesis index of ions reveals the source of groundwater as deeper meteoric water. Thus, the present study indices that the surface water bodies such as ponds, lakes, and swamps are more prone to contamination, leading to unsuitability for irrigational use, as compared to shallow groundwater in the study area, and therefore, appropriate measures must be adopted to reduce the quality deterioration for maximum utilization. � 2021 John Wiley & Sons Ltd.
Evaluation of spatial characteristics of groundwater hydrochemical constituents across different geomorphic units of the�Imphal Valley in Northeast India
(Springer Science and Business Media Deutschland GmbH, 2021-07-05T00:00:00) Singh, Laishram Premananda; Kshetrimayum, K.S.
The assessment of hydrochemical constituents across different geomorphic units of the Imphal valley of Northeastern India has been carried out. Geomorphologically, the valley is broadly demarcated as the�residual hill, piedmont zone, alluvial plain, and flood plain. The Scholler diagram and Box and Whisker plots suggest that the distribution of ions is characterized by dispersed concentrations owing to variation in the�lithologies in the�geomorphic units. The pH value ranges from 6.90 to 7.21 with a mean value of 7.04, indicating neutral water in the residual hill. In the piedmont zone, it ranges from slightly acidic (4.83) to neutral (7.40) with a mean of 6.58. In the alluvial and flood plains, the values range from 6.15 to 7.44, with a mean of 6.84 and 6.07 to 7.14 with an average of 6.73, respectively suggesting neutral water. TDS range shows slight reduction in the�alluvial plain and flood plain owing to effluent water supply from the�rivers whereas, oxidation�reduction potential (Eh) ranges from 8 to ?�19�mV with highest in the�residual hill, indicating reducing condition. Higher Ca2+ and Mg2+ in the�residual hill and piedmont zone are associated with the�cation-exchange process. Na+ and HCO3? are highest in the�alluvial and flood plains due to weathering of sodium-rich montmorillonite or dissolution of halite or nahcolite (NaHCO3) minerals from clay. The scatter plots indicate that the hydrogeochemical processes throughout the geomorphic units are mainly controlled by the�ion exchange, silicate weathering, carbonate weathering, and evaporate dissolution. The hydrochemical facies are characterized by (i) Na�K�Cl, (ii) Ca�Cl, and (iii) Na�K�Ca�Mg�Cl�SO4�HCO3. The residual hill and piedmont zones are dominated by Ca�Cl facies, implying recent meteoric water coupled with halite riched source of water. The alluvial plain is dominated by Na�K�Cl facies, while the flood plain is characterized by Na�K�Ca�Mg�Cl�SO4�HCO3 facies, suggesting the�mixed type resulted from the ion exchange process. These facies suggest that the groundwater belongs to the initial and intermediate stages of chemical evolution indicating fresh quality. � 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Evaluation of hydrochemical facies along the flow path and geomorphic surfaces in a Quaternary Alluvial plain of Barak Valley of Northeast India
(Springer Science and Business Media Deutschland GmbH, 2021-07-07T00:00:00) Khangembam, Sharmila; Singh, Kshetrimayum Krishnakanta
A multi-parameter approach comprising the Stiff diagram, Durov diagram, water table contour map, hydrochemistry, and stable isotope has been used to elucidate characteristics of hydrochemical facies along the groundwater flow across different geomorphic terrains in the Barak Valley of NE India. Three types of hydrochemical facies, (a) Na-HCO3-weak acid type, (b) Na-Mg-HCO3-carbonate-rich type, and (c) Na-Cl-Mg-Ca-HCO3-mixed type, characterize the groundwater. The facies evolve from the acidic type in the recharge zone to mixed type in the alluvial and flood plains. The Base Exchange Index (r-1) values indicate characterization of Na+-HCO3? type (r1 > 1). The Meteoric Genesis Index (r-2) reveals deep meteoric percolation type (r2 <1). The Chloro-alkaline Index-I and II indicate reverse cation anion exchange reaction as the main reaction. The lateral and vertical flows indicate that groundwater flows from the piedmont zone to the alluvial and flood plains. The HCA dendrogram shows three clusters belonging to the piedmont, alluvial, and flood plains, indicating spatial evolution of hydro-facies along the flow path. The isotopic constituents in the groundwater vary along with the flow path. The recharge area exhibits depletion of heavier isotopes (mean ?4.5�), which gradually becomes enriched (mean ?4.1�) along the flow path, towards the plains as the hydro-facies evolves from the Na-HCO3 type to mixed type. � 2021, Saudi Society for Geosciences.
Reconstruction of Quaternary climate in Svalbard: CRN as proxy
(Elsevier, 2021-08-27T00:00:00) Amrutha, K.; Kumar, Pankaj; Khare, Neloy; Pattanaik, Jitendra Kumar
Polar region experienced a large-scale melting of glaciers and sea ice retreat in the recent past. Drastic decrease of ice cover and its foreseen impact on ocean circulations, sea level, and ocean chemistry brought Arctic into the forefront of climate change studies. High-latitude glaciers withstand minor climatic change. However, recent trend of global climatic conditions started influencing polar ice sheet and glacier to an alarming state. Compared to lower latitudes, Arctic is significantly affected by minor changes in temperature and precipitation pattern, referred as �Arctic amplification.� Ice dynamics and impact of climate change on Antarctica ice sheet is different than the Arctic Circle as the surrounding environment and atmospheric circulations acting in these areas are diverse in nature. External forces like Milankovitch Cycles and solar irradiance; atmospheric forces like greenhouse gas concentrations, albedo, and cloud cover; and interaction among these forces are key factors responsible for prevailing climate and its changes in the Arctic Circle. Since few decades, Arctic Circle witnessed complex atmospheric, oceanic, and terrestrial changes. Location of Svalbard archipelago is very crucial in terms of the ocean circulation as it is lying between North Atlantic Ocean and Arctic Ocean. The climate here is largely governed by the North Atlantic Oscillation and thermohaline circulation. However, rise in annual average temperature of Arctic is linked to increase in CO2 concentration and decrease in SO4 gas in the atmosphere. Study suggests that role of SO4 concentration in the atmosphere is more important than the solar irradiation in the Arctic climate. Therefore it is essential to understand how climate has responded to external and atmospheric forces. Svalbard located in the North Atlantic sector of Arctic region has shown a high response to present climate changes due to multiple feedback mechanisms associated with oceanic, atmospheric, and cryosphere processes. � 2021 Elsevier Inc. All rights reserved.
The Miocene fossil lizards from Kutch (Gujarat), India: A rare window to the past diversity of this subcontinent
(Cambridge University Press, 2021-09-06T00:00:00) ?er?ansk�, Andrej; Singh, Ningthoujam Premjit; Patnaik, Rajeev; Sharma, K. Milankumar; Tiwari, Raghavendra Prasad; Sehgal, Ramesh Kumar; Singh, Nongmaithem Amardas; Choudhary, Deepak
The Miocene beds of Kutch in India are well known for their mammalian assemblages, including the extinct ape Sivapithecus, but far less is known about the fossil squamates from this area. Although India with its over 800 reptile species is recognized as one of the global biodiversity hotspots, knowledge of past diversity and paleobiogeography of squamates on this subcontinent is very limited. We here report on new lizard finds, which have been recovered from two stratigraphic levels: the older Palasava locality (dated to the middle Miocene, ca. 14 Ma) and the younger Tapar site (late Miocene, ca. 11-10 Ma). Although fragmentarily preserved, the material described here sheds important light on the composition and paleobiogeography of squamates during the Miocene in South Asia. The older Palasava locality contains cf. Uromastyx s.l. and Varanus sp., the latter representing the oldest record of this taxon in the region of India south of the Himalayas and its occurrence here suggests a mean annual temperature not less than 15�C. The material from the younger Tapar locality consists of an unidentified acrodontan lizard, here questionably placed in agamids, and a skink. The latter shows a resemblance to mabuyines, however, the fragmentary nature of the material does not allow a precise allocation without doubts. The cosmopolitan mabuyines have been suggested to have their origin in Asia, so the potential presence of mabuyines in the Tapar locality might represent the first, but putative, Asian evidence of the occurrence of this group in the Miocene. Copyright � The Author(s), 2021. Published by Cambridge University Press on behalf of The Paleontological Society.
Distribution of rare earth elements and stable isotopic constituents along the groundwater flow paths in the Quaternary deposits of Imphal valley in north-east India
(John Wiley and Sons Ltd, 2021-09-22T00:00:00) Singh, Laishram Premananda; Kshetrimayum, Krishnakanta Singh
Groundwater samples collected from three flow paths (the western, central, and eastern flows) in the shallow aquifers of the Imphal valley of north-east India were examined to study the variation in hydrochemical and rare earth element (REE) characteristics along these flow paths. Each flow path covers a length of around 45 km towards the down gradient. In the western flow, the hydrochemical facies evolved from Na-Cl-Ca to Ca-Na-Mg-Cl-HCO3; in the central flow, it varies from Ca-Mg-Na-Cl to Na-Ca-Cl-HCO3 and in the eastern flow, it changes from Na-Cl to Ca-Mg-HCO3 indicating the evolution of saline water type in the piedmont zone to fresh water type towards the discharge zones around the Loktak Lake. The REE concentration varies along the flow path as the total light REE (LREE) is more enriched than total heavy REE (HREE) in the western and central flows, while LREE is less than HREE in the eastern flow. North American Shale Composite (NASC)-normalized REE patterns in these flow types show significant convex-up NASC-normalized patterns with depleted LREEs. The redox condition in the flow paths is controlled by redox-sensitive elements such as Eh, pH, Fe, Mn, U, Er, Gd, and Nd which vary relatively along with these flows. REE fractionation depicted by (Er/Nd)SN ratios are high around the upgradient and decrease along the down gradient towards Loktak Lake. The isotopic constituents (?18O and ?D) exhibit fluctuations in their ratios along the groundwater flow paths. The residual hill and piedmont zones are characterized by depleted isotopic composition while the alluvial and flood plains show enriched isotopic composition. Thus, the present study elucidates the behavioural change in major hydrochemical parameters including REE and isotopic constituents, along with the groundwater flow, which will provide a holistic view in understanding the evolution of groundwater in terms of its quality, quantity, and origin in the study area. � 2021 John Wiley & Sons Ltd.
A new window to the fossil herpetofauna of India: amphibians and snakes from the Miocene localities of Kutch (Gujarat)
(Springer Science and Business Media Deutschland GmbH, 2021-11-25T00:00:00) Singh, Ningthoujam Premjit; Patnaik, Rajeev; ?er?ansk�, Andrej; Sharma, K Milankumar; Singh, Nongmaithem Amardas; Choudhary, Deepak; Sehgal, Ramesh Kumar
The Miocene beds of Kutch in India are well known for their mammalian assemblages including an extinct ape Sivapithecus. We here report new amphibian and snake fossils, which have been recovered from two stratigraphic levels: the older Palasava locality which is dated to the middle Miocene (~ 14�Ma), whereas the sediments of younger sites at Tappar and Pasuda representing the late Miocene (~ 11�10�Ma). The amphibian material consists only of Rana sp., Ranidae indet. and Anura indet. The snake material is much more diverse and can be allocated to several taxa: Python sp., Acrochordus dehmi, Acrochordus sp., Ahaetuliinae indet. and Alethinophidia indet. Among all these finds, the fossils of Rana sp., Ahaetuliinae indet. and Python sp. described here form the first evidence of these taxa from the Neogene of India. The ectothermic faunas are good indicators of palaeoenvironmental conditions. The ectothermic vertebrate assemblages of these Indian localities indicate a very warm, humid/wet, tropical to sub-tropical environmental conditions during the middle and late Miocene. � 2021, Senckenberg Gesellschaft f�r Naturforschung and Springer-Verlag GmbH Germany, part of Springer Nature.
Quality assessment of surface water and groundwater giving emphasis on water quality index and irrigational indicators in the southeastern part of Manipur Valley, north-east India
(John Wiley and Sons Ltd, 2021-12-21T00:00:00) Thokchom, Laxmi; Kshetrimayum, Krishnakanta Singh
Water quality index (WQI) and irrigational indices for surface water and groundwater in the southeastern part of Manipur Valley in north-east India has been examined. The water samples were collected during the pre-monsoon season in the year 2016. Geologically, the Manipur Valley occurs as an intermontane piedmont-alluvial plain filled with Quaternary alluvium of fluvio-lacustrine origin. The basic chemical parameters of pH, total dissolved solids, electrical conductivity, total hardness, Cl?, HCO3?, Na+, Ca2+, Mg2+, Fe, Mn, and Zn were considered for computing water quality index for drinking water. Irrigational indices such as sodium absorption ratio, sodium percentage, Kelly's index, magnesium hazard, and residual sodium carbonate were calculated for determining the suitability for irrigational use. WQI, SAR, %Na+, KI, MH, RSC suggest that majority of the water samples are suitable for drinking and irrigational uses. They exhibit positive relations among them suggesting that these parameters are dependent over one another. About 20% of the piedmont zone groundwater are unsuitable for both drinking and agricultural purposes. The encrustation of gypsum, halite, and evaporite into the Disang shales enhances the dissolution process of ions such as Cl?, Na+, Ca2+, Mg2+ in the piedmont water leading to quality deterioration. Gibb's plots suggest that the chemical origin of water dominates with rock-weathering process, while hydrochemical facies evolved from the initial stage to intermediate stage. Therefore, proper integrated management and development of water resources is necessary for the effective utilization water resources particularly around the piedmont zone. � 2021 John Wiley & Sons Ltd.
A colubrid snake from the late Miocene of Kutch, Gujarat, India
(Palaeontological Society Of India, 2021-12-31T00:00:00) Singh, Ningthoujam Premjit; Singh, Nongmaithem Amardas; Kumar Sharma, K. Milan; Patnaik, Rajeev; Singh, Yumlembam Priyananda; Chaudhary, Deepak
Fossil snakes are extremely rare in the Indian Neogene records. We report the first record of isolated precloacal vertebrae of a �colubrine� snake from a late Miocene site, Tapar section in Kutch, Gujarat (India). The present specimens differ from the earlier finding of a colubrid from a younger deposit of Labli Member, Utterbaini Formation of Upper Siwaliks (Jammu and Kashmir) by the absence of hyapophyses. The �colubrine� snakes of late Miocene (~11-10 Ma) perhaps lived in a relatively wetter environment compared to the present �colubrine� from Kutch. � 2021 Palaeontological Society Of India. All rights reserved.
Luminescence chronology of Late Quaternary palaeo-lake deposits from the Upper Alaknanda Basin, Uttarakhand, India: Implication to palaeoclimate and depositional settings
(Elsevier Ltd, 2022-01-06T00:00:00) Pattanaik, Jitendra Kumar; Singh, Atul; Kumar, Haldhar; Singh Shah, Sunil; Semwal, Prabhat; Sujith Naik, M.; Nayak, Kalyani; Jaiswal, Manoj K.; Banerjee, Argha; Nainwal, Harish Chandra; Shankar, Ramachandran
Lakes downstream of the glaciers receive glacial meltwater and sediment supply resulting in formation of thick succession of lacustrine deposits. In this work, we have identified one such palaeo-lake deposit in the Upper Alaknanda Basin, close to Badrinath town. The sediments are of lacustrine origin; however the continuity is broken by intermittent fluvial deposits, which indicate changes in the depositional environment. We used Optically Stimulated Luminescence (OSL) dating to develop a robust chronology of the palaeo-lake deposit. Grain size analyses of sediments were carried out to understand the depositional environment, and morphometric analysis of the valley was conducted to obtained clues about the neotectonic activities in the region. The OSL ages show that the deposition of the lake sediments occurred between 21.6 � 4.7 ka to 10.5 � 1.4 ka. Two phases of paleo-lake deposit and subsequent outburst is established from the OSL age, grain size distribution and on the basis of field observations. The high sedimentation rate in the upper part of the deposit indicates an increase in the monsoonal rainfall and glacial retreat post Younger Dryas event. The colder periods are represented by varves and rhythmites, while the warmer periods are represented by thick laminated sand. This study indicates that the glaciers in the Upper Alakanada Basin responded to the fluctuations in the palaeo-climate. � 2022 Elsevier Ltd
Distribution of neotectonic variability between the Kachchh Mainland Fault and Vigodi Fault, Northwestern Mainland Kachchh, Western India
(Elsevier Ltd, 2022-01-13T00:00:00) Kothyari, Girish Ch; Mishra, Sneha; Taloor, Ajay Kumar; Kandregula, Raj Sunil; Pathak, Vamdev; Chauhan, Gaurav
As per the Bureau of Indian Standards (BIS), the Kachchh region of the western peninsular India falls under seismically active region, where the faults experienced existence of several moderate to high magnitude earthquakes in the historic past. The present-day seismicity is mainly concentrated toward the eastern part of Kachchh Mainland Fault (KMF). Even though, the western segment of the KMF does not exhibit seismicity at present, but the tectono-geomorphology of this segment reveals various active geomorphic features which indicates its active nature. In this study, we are focusing on the distribution of neotectonic variability between the western segment of the KMF and the Vigodi Fault (VF), as the detailed geomorphometric studies is lacking in this region, believing that the area is not promising for such studies because the lack of seismicity. Therefore, we applied the conventional morphometric parameters to assess the neotectonic behaviour of the study area. The computed morphometric parameters had been grouped and mixed to create the Relative Index of Active Tectonics (RIAT), Furthermore, we used DInSAR results to estimate the active vertical displacement in between the fault zones which ranges from 0.15 to 0.28 cm. The results of each geomorphic indices indicates active deformation within the central portion of the western KMF and VF zone. This study would be certainly beneficial for seismic hazard assessment and future infrastructure planning of the region. � 2022 The Authors
The 22 June 2020 Mizoram, India earthquake (Mw5.5): an unusual intra-wedge shallow earthquake in the Indo-Burmese Wedge
(Indian Academy of Sciences, 2022-03-08T00:00:00) Malsawma, J.; Lalnuntluanga, Paul; Sailo, Saitluanga; Vanthangliana, V.; Tiwari, R.P.; Gahalaut, V.K.
Earthquakes in the Indo-Burmese arc occur due to interaction of India and Sunda plates along the Indo- Burmese Wedge and Sagaing Fault. Majority of the moderate to major magnitude earthquakes in the Indo-Burmese Wedge occur within the Indian slab and very few of them occur on the plate interface. Earthquakes within the wedge are rare and the 22 June 2020 earthquake of magnitude 5.5 (Mw) on the India�Myanmar border in Mizoram, India, at shallow depth is probably one such earthquake. The earthquake caused moderate damage (maximum intensity VIII on MSK scale) in remote border villages (Vaphai and Chawngtui) with sparse population without any fatality. The earthquake did not seem to be related with the Mat Fault, which was transverse to the north�south trending wedge, as various estimates of mainshock and the region of maximum damage was ~20 km northeast of the surface trace of the Mat Fault. It appeared to be associated with almost north� south oriented Churachandpur Mao Fault (CMF) with dextral slip which mapped extensively and monitored geodetically in the neighbouring regions of Manipur and Nagaland to the north. Occurrence of this shallow depth earthquake may imply that some segment of the CMF might be seismically active, unlike in the north, where it appears to be predominantly aseismic. This implies that the seismic hazard along the CMF may vary along its length. � 2021. All Rights Reserved.
Listriodon dukkar sp. nov. (Suidae, Artiodactyla, Mammalia) from the late Miocene of Pasuda (Gujarat, India): the decline and extinction of the Listriodontinae
(Springer Science and Business Media Deutschland GmbH, 2022-03-17T00:00:00) van der Made, Jan; Choudhary, Deepak; Singh, Ningthoujam Premjit; Sharma, K. Milankumar; Singh, Nongmaithem Amardas; Patnaik, Rajeev
The Listriodontinae were a common and widespread group of Suidae (pigs) that lived in an area extending from Portugal to China and to southern Africa. Here, we describe the new species Listriodon dukkar from Pasuda (Gujarat, India). It shares features with Li. pentapotamiae, evolved from it, and is the last representative of this lineage. The Listriodontinae flourished for about 10 million years, reached their maximum diversity and geographic extension during the Mid-Miocene Climatic Optimum (about 17�13.6�Ma), and their last records are close in age and date to�~ 9.8�Ma in the Indian Subcontinent, 9.78�Ma in Europe, and ~ 10�Ma in Africa. We review the environments in which the last listriodont lineages lived and went extinct. Their extinctions occurred against a background of increasing seasonality, vegetation change, a rise in bovid diversity and abundance, and local events, such as the European Vallesian Crisis and a dramatic drop in tragulid abundance in the Siwaliks. However, changes in the atmospheric pCO2 may have contributed to their decline and extinction in all their geographic distribution. Decreasing pCO2 is expected to have decreased sugar content and increased protein content of leaves and fruit. Hindgut fermenting Suoidea have higher protein requirements, while foregut fermenting Suoidea are more efficient in digesting sugars. Listriodontinae were probably foregut fermenters and were less well adapted in a low pCO2 world. � 2022, The Author(s).
Biogeochemistry of the antarctic coasts: Implications for biodiversity and climate change
(Wiley Blackwell, 2022-04-01T00:00:00) Karayakath, Amrutha; Pattanaik, Jitendra K.; Saini, Khem C.; Kundu, Pushpendu; Bast, Felix
Notwithstanding its largely lifeless appearance, Antarctica hosts considerable biodiversity and ecosystem (trophic-level) complexity. Antarctic soils, ice-covered areas, coastal regions, and the surrounding Southern Ocean contributes to this biodiversity. However, studies related to the number of species present, how and where they are located and their influence on the ecosystem processes are still scarce. Biodiversity and biogeochemical cycles often coincide with climate change studies. Photosynthetic carbon fixation by phytoplanktons in the Antarctic coasts influences the atmospheric CO2 levels. On a geological timescale, such processes determine the climate. In this chapter, studies on Essential Ocean Variables and elemental cycles in Antarctica are reviewed to understand the biogeochemistry of the coast of Antarctica, and how these parameters and cycles influence the different coastal features of Antarctica. In the recent past, Antarctica has experienced a rapid rate of warming that in turn has threatened its biodiversity. The effects of climate change on biogeochemical parameters and their further consequences are therefore discussed here. The second half of this chapter deals with the prokaryotic as well as eukaryotic microbial diversities of Antarctica, and the implications they hold for climate change. � 2022 John Wiley & Sons, Inc. All rights reserved.
Career challenges for young independent researchers in India
(Indian Academy of Sciences, 2022-04-15T00:00:00) Agashe, Deepa; Maheshwary, Sugandha; Pattanaik, Jitendra Kumar; Prakash, Jai; Bhatt, Pragya; Arya, S.S.; Chatterjee, Sriparna; Kumar, Pankaj; Singh, Paramdeep; Abbas, Nazia; Sharma, Chandra Shekhar; Chaudhuri, Chirasree Roy; Devi, Pooja
The scientific enterprise in India has grown dramatically in the past few decades, with research emerging as a viable and important career option for students of science. The country thus has a large population of young scientists in the early stages of establishing their independent research careers. While this demographic is arguably the most important group that will determine the future of scientific research in India, their status and concerns are poorly understood. The Indian National Young Academy of Sciences conducted a national survey to better understand and present the challenges faced by them. Through a structured questionnaire, we sought the views of research-ers below 45 years of age. Here, we summarize the responses from 854 participants across multiple early career stages. We highlight key challenges faced by these scientists in establishing an inde-pendent research career, and suggest steps to address them. � 2022,Current Science.All Rights Reserved
Evaluation of seasonal dynamics of the surface water hydrochemistry using multivariate statistical techniques and aquatic macrophyte productivity in a mountainous lake, Northeast India
(Springer Science and Business Media Deutschland GmbH, 2022-05-13T00:00:00) Singh, Konthoujam Khelchandra; Singh, Kshetrimayum Krishnakanta; Usha, Khuraijam; Das, Subhasish; Singh, Salam Shantikumar
The present work elucidates the effective application of multivariate statistics in understanding the probable relations between surface water hydrochemistry and aquatic macrophyte productivity and their underlying seasonal dynamics in a remote mountainous lake of northeast India. The result of hierarchical cluster analysis revealed three distinct clusters corresponding to the pre-monsoon (35.42%), post-monsoon (52.08%), and monsoon (12.50%) seasons. The factor analysis yielded three principal components suggesting the sediment flux, farming discharge, domestic waste, bacterial oxidation of sulfur compounds, and dissolution of plant matters associated with dissolved feldspar minerals as the influential factors. The lake hydrochemistry also varied significantly, both spatially and temporally implying geogenic weathering processes from rock-soil-water interactions. Overall, sixteen aquatic macrophytes were identified, and their monthly and daily net primary productivity varied considerably in different seasons. Regression analysis highlighted the effect of temperature, total dissolved solids, electrical conductivity, and turbidity on the seasonal fluctuations in macrophyte productivity. Overall, the study provides insights into seasonal variation in the lake water chemistry and highlights the role of statistical tools in understanding the fragile aquatic ecosystems over cost-, labor-, and time-intensive inventory studies. � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Geochronology and oxygen fugacity of the pelitic granulite from the Diwani hills, NE Gujarat (NW India)
(Cambridge University Press, 2022-08-01T00:00:00) Kumar, Manish; Prakash, D.; Singh, C.K.; Yadav, M.K.; Tewari, S.; Singh, Pradip K.; Mahanta, B.
The Diwani hills are located SE of Balaram-Abu Road in the Banaskantha district of north Gujarat. The crystalline rocks of the Diwani hill area are a diverse assemblage of Precambrian metamorphic and igneous rocks. These rocks are petrologically more complex and date back to the Aravallis or earlier. The mineralogical assemblages such as grt-sp-opx-qz of these rocks indicate their origin in anhydrous or dry conditions, implying metamorphism under pyroxene granulite facies. These granulitic rocks were subjected to Delhi orogenic deformation and were later intruded by the Erinpura granite. Textural and microstructural relationships, mineral chemistry, P-T-X pseudosection modelling and the oxidation state of pelitic granulites from the Diwani hill area of north Gujarat are all part of the current approach. The winTWQ program and pseudosection modelling in the NCKFMASHTO model system utilizing Perple_X software were used to restrict the P-T evolution of these pelitic granulites. The unification of these estimates shows that the pelitic granulites reached their pressure and temperature maxima at 8.6 kbar and 770 �C, respectively. The oxygen fugacity (log fO2) versus temperature computations at 6.2 kbar revealed log fO2-T values of -13.0 and 765 �C, respectively. The electron microprobe dating of monazite grains separated from the granulites of the Diwani hills yields ages ranging from 769 Ma to 855 Ma. The electron microprobe dating presented here from the Diwani hills provides evidence for a Neoproterozoic (Tonian) metamorphic event in the Aravalli-Delhi Mobile Belt. � The Author(s), 2022. Published by Cambridge University Press.
New rodents shed light on the age and ecology of late Miocene ape locality of Tapar (Gujarat, India)
(Taylor and Francis Ltd., 2022-08-05T00:00:00) Patnaik, Rajeev; Singh, Ningthoujam Premjit; Sharma, K. Milankumar; Singh, Nongmaithem Amardas; Choudhary, Deepak; Singh, Y. Priyananda; Kumar, Rohit; Wazir, Wasim Abass; Sahni, Ashok
The Miocene ape (Sivapithecus) locality of Tapar in Kutch (Gujarat, India) has yielded a diverse rodent assemblage that includes: a new murine Progonomys prasadi sp. nov., a new gerbilline Myocricetodon gujaratensis sp. nov., a new rhizomyne Kanisamys kutchensis sp. nov. and a new sciurine Tamias gilaharee sp. nov., beside additional remains of Progonomys morganae, Dakkamys asiaticus, Prokanisamys sp., Sayimys sivalensis and Democricetodon fejfari. Morphometric and PAUP based phylogenetic analyses place Progonomys prasadi sp. nov. within the Progonomys lineage. The cladogram obtained for the Siwalik murines suggest that Progonomys was ancestral to all the modern and one extinct murine genera recovered from the Siwaliks. The advanced features of Myocricetodon gujaratensis sp. nov. indicate that it was an immigrant to the subcontinent in the late Miocene. The cladistic analysis performed on Kanisamys kutchensis sp. nov. shows that it shared several advanced characters with contemporaneous Kanisamys nagrii and Kanisamys sivalensis. Based on the biostratigraphical ranges of Siwalik rodents and the co-occurrence of advanced forms of new and already reported murines, a new gerbilline and a new sciurine, we propose an age of ?10 Ma to the primate-bearing Tapar locality. Already reported stable isotope data on murines, and ecological preferences of modern counterparts of the fossil rodents and associated sharks and rays from Tapar locality, indicate that the Miocene ape Sivapithecus may have lived in a subtropical monsoonal forest close to the coast, very different from the present day arid conditions. http://zoobank.org/urn:lsid:zoobank.org:pub:12CE1B44-22A0-450F-9588-6C7F25242771. � The Trustees of the Natural History Museum, London 2022. All rights reserved.
Collective Affirmation in Action: Understanding the Success of Lockdown in India During the First Wave of the COVID-19 Pandemic
(Gonabad University of Medical Sciences, 2022-08-29T00:00:00) Tiwari, Gyanesh Kumar; Kashyap, Anil Kumar; Rai, Pramod Kumar; Tiwari, Raghavendra Prasad; Pandey, Ruchi
Background: This study explores the role of collective affirmation in attracting mass cooperation to motivate people to observe preventive measures during the COVID-19 pandemic. Methods: Using a qualitative research design, a heterogeneous sample (n=32) comprising postgraduate (n=10) and doctorates (n=22) was chosen and the data were collected through semi-structured interviews. The interview contents were audiotaped, transcribed verbatim, and analyzed via the thematic analysis method. Results: Five themes were generated in this study: perceived psychological distress, pandemic as a serious challenge to the national interest and human existence, the Janata curfew as a positive faith of the government in the abilities of Indians, lockdown as a strong faith of the government in the unshakable support of the Indians and strong affinity and pride of the Indians in their cultural heritage. The novelty, suddenness, and incurability of COVID-19 caused a set of perceived psychological distress and danger to individual and collective life. The Janata (public) curfew was perceived as a curfew of the people, by the people, and for the people. The lockdown denoted a strong faith of the Indian government in the positive virtues of the Indian people and vice versa. The mass support and adherence to the suggested preventive government measures were facilitated by collective affirmation of the well-known positive Indian cultural values (e.g. humanism, interdependence, collective pride, compassion, universal brotherhood, and so on) to the world. Conclusion: Collective affirmation inherent in the Indian cultural values catalyzed mass behavior change in the form of adherence to the essential restrictions and recommendations. Collective affirmation may have occurred because of the perceived faith of the government in the virtues of the Indians and their perceived administrative capability of the government. A culture-specific collective affirmation seems to emerge which initiated mass behavior changes leading to a successful lockdown. � 2022, Gonabad University of Medical Sciences. All rights reserved.

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