Origins of Soft-Sediment Deformation Structures from the Batang Paleodammed Lakes in the Upper Jinsha River, SE Tibetan Plateau

摘要

Multiple levels of preserved soft-sediment deformation structures occur in sediments deposited in the paleodammed lakes in the Batang-Zhongza reaches of the upper Jinsha River Valley, southeast Tibetan Plateau. These deformation structures include folded layers, convoluted layers, ball-and-pillow structures, recumbent lamination, waterescape structures, and small-scale landslide. Combining the assessments of depositional facies, potential triggers, paleoenvironmental context, we conclude that the probable trigger agents of this deformation were earthquakes, slides, and debris flows. The seismically-induced soft-sediment deformation structures provide new substantial evidence for the existence of active tectonics and paleo-earthquakes in the Batang area since the Holocene.