Late Miocene to Quaternary slip history across the Qiulitag anticline in the southern Tianshan piedmont

International audienceIn this study, we reconstruct the Miocene to Quaternary shortening history across the Qiultag anticline, a complex fault-bend fold located in southern Tianshan. We studied the Yaha and Kuche sections, where we combined surface structural measurements and seismic imaging to model the stratigraphic horizons. The history of folding was reconstructed based on magnetostratigraphic analyses and eight cosmogenic burial ages in Kuche. Pleistocene deformation rates were also quantified in Yaha based on a deformed fluvial terrace that we dated to ~67 ka using a cosmogenic depth profile. Our results suggest that the fold grew at a mean slip rate of 0.9-1.3 mm/a in both sections but accelerated to ~2.5 mm/a during the Pleistocene in Kuche. These results support a migration of the deformation toward the basin during the Pleistocene and suggest that most of the present deformation of the Tianshan is accommodated across the external structures of the range