A Preliminary Study on the Soft-Sediment Deformation Structures in the Late Quaternary Lacustrine Sediments at Tashkorgan,Northeastern Pamir, China
  • 【摘要】

    This study identified soft-sediment deformation structures (SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo-dammed lake at Tashkorgan,northeastern Pamir.The observed def... 展开>>This study identified soft-sediment deformation structures (SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo-dammed lake at Tashkorgan,northeastern Pamir.The observed deformation structures include sand dykes,liquefied diapir and convolute structures,gravity induced SSDS,and thixotropic pillar and tabular structures.We conducted a preliminary study on the morphology,formation and trigger mechanisms of pillar and tabular structures formed by liquefaction of underlying coarse sand and thixotropy of the upper silty clay.The regional tectonic setting and distribution of lacustrine strata indicate that the most probable trigger for the SSDS in lacustrine sediments was seismic activity,with an approximate earthquake magnitude of M>6.0;the potential seismogenic fault is the southern part of the Kongur normal fault extensional system.AMS 14C dating results indicate that the SSDS were formed by seismic events occurring between 26050±100 yrBP and 22710±80 yrBP,implying intense fault activity in this region during the late Pleistocene.This study provides new evidence for understanding tectonic activity and regional geodynamics in western China. 收起<<

  • 【作者】

  • 【作者单位】

    College of Architecture and Civil Engineering/College of Architecture and Civil Engineering/State Key Laboratory of Earthquake Dynamics

  • 【刊期】

    地质学报(英文版) SCI 2018年4期

  • 【关键词】

    soft-sediment deformation structures  lacustrine sediment  Pamir  liquefaction  thixotropy  paleo-seismicity 

  • 【基金项目】

    We are grateful to Prof.Qiao Xiufu and Su Dechen for the valuable comments and helpful discussions on the early version of the manuscript.We thank for editor and anonymous reviewers for valuable comments on the suggestions and improvements on the manuscript.This work was financially supported by the the Open Fund of State Key Laboratory of Earthquake Dynamics