Trace fossil evidences of an Early Miocene paleoseismic event and depositional regime change from the Kutch(Kachchh)Basin

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外文摘要：Unconsolidated siliciclastic sediments can undergo post-burial deformation,which leads to the formation of distinctive sedimentary structures,known as soft-sediment deformation structures(SSDS).The presence of a series of sand volcanoes confined to a particular lithostratigraphic horizon can represent a paleoseismic activity and,thereby,exemplifies the concept of"seismite".The Kutch Basin has been a tectonically active region since the initiation of eastern Gondwana rifting followed by a tectonic inversion during the Cenozoic due to the collision of the Indian and Eurasian plates.A stratum-bound series of sand volcanoes belonging to the Khari Nadi Formation(KNF)is exposed along the banks of Khari River.They separate the shallow marine deposits below and non-marine deposits above with their characteristic marine and paleosol trace fossil suites,respectively.Although a seismogenic origin has been much debated for the SSDS,the ichnofabric analysis of the sand-volcano-bearing stratum unequivocally points toward such an origin under a shallow seafloor condition.In addition to the sedimentary regime change from an open shallow-marine setting to a continental depositional environment concomitant with basinal uplift,the behavior of the bur-rowing crustaceans testifies to a syn-depositional development of a fault network associated with the fluid-ization,sand volcanism,and the resilience of the trace-producers in surviving those processes until the sedimentary regime change in the overlying strata.Although the ichno-sedimentological evidence apparently differs from the previous works that proposed a continuous base-level rise from the beginning of deposition of the Khari Nadi Formation up to the middle part of the overlying Chhasra Formation,the paleoseismic activity,its ichnologic signature,and the depositional regime change refer to a higher-resolution(i.e.,lower-order)sequence-stratigraphic change causing a short-duration regression within a longer-duration cycle of base-level rise.

外文关键词：

Sand volcanoSeismiteIchnologyKhari Nadi FormationKutch BasinKachchh Basin

作者：

Ayush Srivastava、Sudipta Dasgupta、Krishanu Chatterjee、Mohuli Das

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作者单位：

Bombay Ichnos Research Group,Department of Earth Sciences,Indian Institute of Technology Bombay(IIT Bombay),Powai,Mumbai,Maharashtra 400076,India

基金：

Science and Engineering Research Board(SERB)Government of IndiaIndustrial Research and Consultancy Centre(IRCC)IIT BombayCouncil of Scientific and Industrial Research(CSIR)(doctoral scholarship for AS)University Grants Commission(doctoral scholarship for KC)IIT Bombay and Ministry of Education of India(doctoral scholarship for MD)

项目编号：

CRG/2018/000259RD/0517-IRCCSH0-035

出版年：

2024

DOI：

10.1016/j.jop.2023.10.004

古地理学报(英文版)

影响因子：0.186

ISSN：

年,卷(期)：2024.13(1)

参考文献量82