Slip rate of the Qilian Shan frontal thrust, China, as derived from surface exposure dating

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Ongoing crustal shortening and uplift in the Qilian Shan tectonic province (China) leads to lateral growth of the Tibetan Plateau toward the north-northeast. In the western Qilian Shan, the most prominent expression of active shortening is a fault propagation fold associated with the range-bounding Qilian Shan frontal thrust. Two rivers flowing across the active structure have formed three main terrace levels in the uplifting hangingwall. This environment is thus exemplary of tectonic and surficial processes involved in mountain building. We propose that 21Ne and 10Be surface-exposure dating of these river terraces combined with a topographic survey will constrain the rates of uplift and shortening across the Qilian Shan frontal thrust. In addition, a comparison between the "incremental strain" recorded by the terraces and the "finite strain" of the fault propagation fold will allow to estimate the onset of faulting. Our study will provide a better understandig of the spatial and temporal evolution of deformation along the margins of continental plateaus, applicable to both collisional and non-collisional settings.