Soft-sediment deformation structures in the Mesoproterozoic Kaimur Sandstone,Vindhyan Supergroup(Central India),and their seismotectonic implications  

作　　者：Jayanta Kumar Pati Anuj Kumar Singh 

机构地区：[1]Department of Earth and Planetary Sciences,Faculty of Science,University of Allahabad,Prayagraj,211002,India [2]National Centre of Experimental Mineralogy and Petrology,14 Chatham Lines,University of Allahabad,Prayagraj,211002,India

出　　处：《Journal of Palaeogeography》2023年第3期463-486,共24页古地理学报（英文版）

基　　金：the Council of Scientific and Industrial Research, New Delhi, Government of India, for awarding him Shyama Prasad Mukherjee Fellowship [SPM-09/001(0328)/2020-EMRI];the Department of Science and Technology, Government of India, for the INSPIRE Fellowship [IF170168]

摘　　要：The unequivocal identification of soft-sediment deformation structures(SSDS)is a significant attribute to constrain the effect of transient geological events in the spatio-temporal evolution of ancient sedimentary basins.This paper reports and discusses,for the first time,the occurrence of several cm-to dm-scale SSDS within sandstone successions of the Mesoproterozoic Kaimur Group(Vindhyan Supergroup),exposed at the Hanumandhara Hill of Chitrakoot-Satna border region,Madhya Pradesh State,India.The SSDS are confined to a deformed interval comprising seven individual sedimentary units of variable composition and texture,which are sandwiched between nearly horizontally undeformed sandstone beds.The SSDS consist of load structures(load casts,flame structures,pseudonodules and ball-and-pillow structures),contorted lamination,convolute lamination,boudins and pinch-and-swell structures,deformed cross-stratification,slump structures,clastic injections,fluid escape structures,and syn-sedimentary fractures/faults.The pre-sent study suggests that the formation of these SSDS is essentially related to a combination of processes(gravitational instability,liquefaction,fluidization,and fluid escape)predominantly induced by seismic shocks.In addition,the restricted occurrence of fractures/faults in these deformed layers emphasizes the passage of seismically-induced Rayleigh waves.Considering the observed types of SSDS,their lateral homo-geneity and geographic distribution along with the geodynamic framework of the Vindhyan Basin,the whole area can be tentatively attributed to having experienced moderate-to high-magnitude(M≥5)seismicity.The present study combined with earlier reports of seismically-induced SSDS,from other regionally disposed formations belonging to the Lower(e.g.,Kajrahat Limestone,Chopan Porcellanite,Koldaha Shale,Rohtas Limestone,and Glauconitic Sandstone of the Semri Group)and Upper(e.g.,Bhander Limestone of the Bhander Group)Vindhyan Supergroup,respectively,provides evidence for the constant regional-scale s

关 键 词：Soft-sediment deformation structures SSDS SEISMITES Kaimur Group Vindhyan Basin Sand-stone Central India 

分 类 号：P548[天文地球—构造地质学] P315.2[天文地球—地质学]