Seismically triggered soft-sediment deformation structures in Tashkorgan lacustrine sediments, northeastern Pamir, China

Soft-sediment deformation structures (SSDSs) are widely developed in the lacustrine sediments of paleo-dammed lakes in tectonically active regions and contain a wealth of information on regional fault activity. In this study, multiple SSDSs (load structures, small-scale slump structures, droplets, diapir and pillow structures, silty-clay pillars and large-scale slump structures) were identified in the strata of the Late Pleistocene lacustrine sedi-ments in the Tashkorgan River drainage in northeaster n Pamir. The deformation mechanisms of the SSDSs were related to the liquefaction, fluidization and thixotropic behaviors. The regional tectonic settings and SSDS fea-tures point toward a trigger mechanism with seismic activities and indicate that the seismogenic faults were possibly related to the southern part of the Kongur Shan extensional system. Accelerator mass spectrometr y (AMS) radiocarbon dating data showed that the SSDSs in the Tashkorgan lacustrine sediments formed 30,221-29,932 cal BP and 25,825-25,317 cal BP. The results of this study improve ou r understanding of fault activity and geodynamic processes in northeaster n Pamir during the Late Pleistocene.

Automated summary

Soft-sediment deformation structures (SSDSs) are widely developed in lacustrine sediments in tectonically active regions, containing valuable information on regional fault activity. This study identified multiple SSDSs in Late Pleistocene lacustrine sediments in northeastern Pamir, showing deformation mechanisms related to liquefaction, fluidization, and thixotropic behaviors. AMS radiocarbon dating data revealed formation periods of the SSDSs, indicating a possible relation to seismic activities and enhancing understanding of fault activity in the region.