Evolution of Neoproterozoic siliciclastic Kerur Formation in the light of sequence stratigraphic framework: Badami Basin, Karnataka, India  

作　　者：Soumik Mukhopadhyay Nipun Ghosh Pradip Samanta Arunava Sen Soumyadeep Bose 

机构地区：[1]Department of Geological Sciences,Jadavpur University,Kolkata 700032,India [2]Atomic Minerals Directorate for Exploration and Research,Shillong 793019,India [3]Department of Geology,University of North Bengal,Darjeeling,Siliguri 734013,India

出　　处：《Journal of Palaeogeography》2024年第4期706-737,共32页古地理学报（英文版）

摘　　要：Field-based sedimentology,state of the art facies analysis and sequence stratigraphic framework analysis have revealed the controls of local and global tectonics,basin-marginal slope,climate and changes in relative sea level (RSL) over the sedimentation pattern and evolution of a Neoproterozoic Kerur Formation within the Badami Group of Kaladgi Supergroup in India.The entire succession shows three major cycles of deposition.Facies study and fluvial architectural elemental analysis suggest considerable variations in depositional environments as well as palaeogeography.A transition from basin-margin alluvial cone deposits to braided system,initially with fluctuating ephemeral flows then to a steadier semi-perennial nature,is discernible within the 1^(st) cycle,in response to decreasing depositional slope with rising water table.The initial alluvial cone and braided ephemeral streams of high slope areas is designated as a product of low accommodation systems tract (LAST),while the semi-perennial system with steadier flows,representing the axial river of the initial rift valley,appears to be a product of high-accommodation systems tract (HAST).The 2^(nd) cycle begins with a perennial and steady braided river system and grades upward to a shallow marine succession,comprising wave-dominated,well-sorted sandstone,with a granular transgressive lag at the base.Thus,the bottommost fluvial interval of the 2^(nd) cycle constitutes the lowstand systems tract (LST).The marine succession represents deposits of outer shelf offshore to foreshore-beach settings and is composed of an initially deepening and fining upward transgressive systems tract (TST),followed by a coarsening and shallowing upward highstand systems tract (HST) with a maximum marine flooding surface (MFS) in between,demarcated by a shale-rich condensed zone.The 3^(rd) cycle,with its prograding alluvial fan and aggrading braided fluvial deposits and restricted occurrence,represents only the low accommodation systems tract(LAST) with a subaerial unconformity at the

关 键 词：Neoproterozoic Kerur Formation Facies and architectural elemental analysis PALAEOGEOGRAPHY Sequence stratigraphy Basin evolution 

分 类 号：P534.3[天文地球—古生物学与地层学] P539.2[天文地球—地质学] P531