Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173924
N.R. Ramesh
{"title":"H.M. Ramachandra (1954-2024) - A Gem of a Geologist and a Perfect Gentleman","authors":"N.R. Ramesh","doi":"10.17491/jgsi/2024/173924","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173924","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141277751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173910
S. K. Beja, Waseem Raza, S. M. Ahmad, Shakeel Ahmed, B. Banerjee
We report here δ18O and δ13C records of a modern Porites and a fossil Favia coral from the Lakshadweep Island to decipher seasonal changes in seawater characteristics. The modern coral was obtained by underwater drilling of a live Porites colony of Kavaratti Island, whereas fossil Favia coral was collected from a nearby location of the same island. Our interpretation is mainly based on high-precision isotopic measurements of 378 samples. The skeleton δ18O values of Porites coral, representing a period of 25 years (between 1984 and 2008 AD), vary between – 5.1‰ and – 4.37‰ vs VPDB, whereas δ18O values of a >400 yrs old fossil Favia coral exhibit significantly greater δ18O values, ranging from – 4.75 to – 3.39‰ vs VPDB. A plot of δ18O time series of modern Porites coral with the available sea surface temperature (SST) record of the study area exhibits an inverse relationship between coral δ18O and regional SST changes, suggesting temperature as the dominant factor for controlling δ18O in seasonal bands of corals. Seasonal variations in δ13C values in both the scleractinian corals were probably influenced mainly by variations in δ13C of dissolved inorganic carbon (DIC). However, carbon isotopic records also indicate the effects of biological (metabolic) processes on their δ13C. The greater seasonal amplitude recorded in δ18O and δ13C values of Favia coral than in Porites coral implies a marked difference in their metabolic processes.
{"title":"High-resolution Oxygen and Carbon Isotopic Records of a Modern and a Fossil Coral from the Lakshadweep Archipelago","authors":"S. K. Beja, Waseem Raza, S. M. Ahmad, Shakeel Ahmed, B. Banerjee","doi":"10.17491/jgsi/2024/173910","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173910","url":null,"abstract":"\u0000 We report here δ18O and δ13C records of a modern Porites and a fossil Favia coral from the Lakshadweep Island to decipher seasonal changes in seawater characteristics. The modern coral was obtained by underwater drilling of a live Porites colony of Kavaratti Island, whereas fossil Favia coral was collected from a nearby location of the same island. Our interpretation is mainly based on high-precision isotopic measurements of 378 samples. The skeleton δ18O values of Porites coral, representing a period of 25 years (between 1984 and 2008 AD), vary between – 5.1‰ and – 4.37‰ vs VPDB, whereas δ18O values of a >400 yrs old fossil Favia coral exhibit significantly greater δ18O values, ranging from – 4.75 to – 3.39‰ vs VPDB. A plot of δ18O time series of modern Porites coral with the available sea surface temperature (SST) record of the study area exhibits an inverse relationship between coral δ18O and regional SST changes, suggesting temperature as the dominant factor for controlling δ18O in seasonal bands of corals. Seasonal variations in δ13C values in both the scleractinian corals were probably influenced mainly by variations in δ13C of dissolved inorganic carbon (DIC). However, carbon isotopic records also indicate the effects of biological (metabolic) processes on their δ13C. The greater seasonal amplitude recorded in δ18O and δ13C values of Favia coral than in Porites coral implies a marked difference in their metabolic processes.","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141277000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173921
Girish Gopinath, A. L. Achu, Rani Varghese
{"title":"Report on the Training Course on Geospatial Technology for Natural Resources Management Sponsored by the Directorate of Environment & Climate Change (DoECC), Government of Kerala","authors":"Girish Gopinath, A. L. Achu, Rani Varghese","doi":"10.17491/jgsi/2024/173921","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173921","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141276497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173906
Subhajyoti Das
{"title":"Water Stress in Bengaluru, Silicon City","authors":"Subhajyoti Das","doi":"10.17491/jgsi/2024/173906","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173906","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141234604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173909
Pradeep Kumar Yadav, Uma Shankar
Pore pressure is a crucial geomechanical parameter, to decide the mud density while well drilling. The mud weight should be between formation pressure (pore pressure) and the fracture gradient of the reservoir rock, otherwise various kind of unwanted incidents like, kicks, blowout, breakout, well collapse, mud loss and lost circulation can happen; which can increase the cost of drilling and in worst case it may lead to a dangerous accident and consequently loss of life and assets at drilling site. In this study we are trying to find pore pressure within water bearing shale formations and gas hydrate (solid) bearing sand formation of four wells of Area B in the Krishna-Godavari Basin, namely, NGHP-02-17A, 19A, 22A, and 23A. Bower’s sonic, Eaton’s resistivity and Eaton’s sonic empirical equations have been used to estimate effective stress in the water-bearing shale formation. In gas hydrate-bearing sand formations these empirical equations cannot be useful for effective stress or pore pressure estimation and hence a linear model based on pressure-core data, relating effective stress and depth in meter below seafloor (mbsf) is generated .This model is applicable for the effective stress estimation in gas hydrate bearing sand formations of the Krishna-Godavari basin. The effective stress estimated from linear model and from core data are found in good agreement in all the wells. At site NGHP-02-23, in-situ pore-pressure was measured between depth of 270.38 to 271.38 mbsf with the help of modular dynamic formation tester (MDT) tool. The in-situ pore pressure (28.2 MPa) and estimated pore pressure (27.8 MPa) from the linear model are found in good agreement. Further, fracture pressures from Matthew-Kelly and Eaton’s method were estimated. The mud weight base on the reported mud density 1.3g/cc are found to higher than the pore pressures and lower than the fracture pressures and hence fulfil the criteria for safe drilling.
{"title":"Linear Model for Pore Pressure Predication in Gas Hydrate-bearing Sand Formation of Krishna-Godavari Basin (India) – A Case Study","authors":"Pradeep Kumar Yadav, Uma Shankar","doi":"10.17491/jgsi/2024/173909","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173909","url":null,"abstract":"\u0000 Pore pressure is a crucial geomechanical parameter, to decide the mud density while well drilling. The mud weight should be between formation pressure (pore pressure) and the fracture gradient of the reservoir rock, otherwise various kind of unwanted incidents like, kicks, blowout, breakout, well collapse, mud loss and lost circulation can happen; which can increase the cost of drilling and in worst case it may lead to a dangerous accident and consequently loss of life and assets at drilling site. In this study we are trying to find pore pressure within water bearing shale formations and gas hydrate (solid) bearing sand formation of four wells of Area B in the Krishna-Godavari Basin, namely, NGHP-02-17A, 19A, 22A, and 23A. Bower’s sonic, Eaton’s resistivity and Eaton’s sonic empirical equations have been used to estimate effective stress in the water-bearing shale formation. In gas hydrate-bearing sand formations these empirical equations cannot be useful for effective stress or pore pressure estimation and hence a linear model based on pressure-core data, relating effective stress and depth in meter below seafloor (mbsf) is generated .This model is applicable for the effective stress estimation in gas hydrate bearing sand formations of the Krishna-Godavari basin. The effective stress estimated from linear model and from core data are found in good agreement in all the wells. At site NGHP-02-23, in-situ pore-pressure was measured between depth of 270.38 to 271.38 mbsf with the help of modular dynamic formation tester (MDT) tool. The in-situ pore pressure (28.2 MPa) and estimated pore pressure (27.8 MPa) from the linear model are found in good agreement. Further, fracture pressures from Matthew-Kelly and Eaton’s method were estimated. The mud weight base on the reported mud density 1.3g/cc are found to higher than the pore pressures and lower than the fracture pressures and hence fulfil the criteria for safe drilling.","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141278451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173920
Vivek S Kale, P. Krishnamurthy, S.J. Sangode
{"title":"Preliminary Meeting for Evolving a Comprehensive Database on Deccan Volcanic Province","authors":"Vivek S Kale, P. Krishnamurthy, S.J. Sangode","doi":"10.17491/jgsi/2024/173920","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173920","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141281535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173925
Om N. Bhargava
{"title":"John Alfred Talent (1932 - 2024)","authors":"Om N. Bhargava","doi":"10.17491/jgsi/2024/173925","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173925","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141274722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173914
Shashwata Chatterjee, P. Sultana, Jayalekshmi S., Rohit Ralli
Oedometer tests for the determination of compression index are time-consuming and need to be meticulously performed. Hence, empirical equations need to be formulated to predict the value of the compression index. In the current study, regression models have been developed based on correlation studies for lightly overconsolidated cohesive-frictional soil obtained from a site in the Southwest Delhi district, India. Statistical analyses have been performed on 80 observations from consolidation tests conducted on the samples retrieved from 58 boreholes. Based on the correlation analyses, it is found that the existing empirical correlations estimate the compression index erroneously. So, formulating an empirical equation for the study area is important. The soil properties, such as natural water content and liquid limit, are unsuitable variables to predict the compression index. These findings are not consonant with those of previous research as these engage the mentioned parameters in modelling the compression index. The several univariate and multivariate regression equations developed in this study are tested for validation using the coefficient of determina ion. Among the several regression models examined, the logarithmic equation of the compression index contributes to accurate prediction.
{"title":"Estimation of Compression Index of Cohesive-Frictional Soil in Southwest Delhi District Using Statistical Correlations","authors":"Shashwata Chatterjee, P. Sultana, Jayalekshmi S., Rohit Ralli","doi":"10.17491/jgsi/2024/173914","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173914","url":null,"abstract":"\u0000 Oedometer tests for the determination of compression index are time-consuming and need to be meticulously performed. Hence, empirical equations need to be formulated to predict the value of the compression index. In the current study, regression models have been developed based on correlation studies for lightly overconsolidated cohesive-frictional soil obtained from a site in the Southwest Delhi district, India. Statistical analyses have been performed on 80 observations from consolidation tests conducted on the samples retrieved from 58 boreholes. Based on the correlation analyses, it is found that the existing empirical correlations estimate the compression index erroneously. So, formulating an empirical equation for the study area is important. The soil properties, such as natural water content and liquid limit, are unsuitable variables to predict the compression index. These findings are not consonant with those of previous research as these engage the mentioned parameters in modelling the compression index. The several univariate and multivariate regression equations developed in this study are tested for validation using the coefficient of determina ion. Among the several regression models examined, the logarithmic equation of the compression index contributes to accurate prediction.","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141278547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173922
C.S. Vishnu
{"title":"Deformation Mechanisms, Processes and Fabric Analysis in Earth Materials from the Global to the Nano scale – Methods and Applications– A Report of the IASGT Workshop-2024 held at IIT Kharagpur, India","authors":"C.S. Vishnu","doi":"10.17491/jgsi/2024/173922","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173922","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141279768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.17491/jgsi/2024/173923
U. Pandey
{"title":"Geochronology and Isotope Geochemistry of Uranium Deposits of India","authors":"U. Pandey","doi":"10.17491/jgsi/2024/173923","DOIUrl":"https://doi.org/10.17491/jgsi/2024/173923","url":null,"abstract":"","PeriodicalId":50001,"journal":{"name":"Journal of the Geological Society of India","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141276614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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