Middle-late Miocene rapid exhumation of the southern Qilian Shan and implications for propagation of the Tibetan Plateau

The northeastern Tibetan Plateau is a key place to test several contrasting tectonic models regarding uplift of the plateau. However, our understanding of the Cenozoic deformation history of the northeastern Tibetan Plateau is incomplete, preventing a clear understanding of the uplift and deformation mechanisms of this plateau. Here, we present new apatite (U-Th)/He ages from the hanging wall of the Qaidam Shan fault, which lies on the southern margin of the Qilian Shan. Our results reveal a phase of rapid exhumation during 15–10 Ma driven by thrusting accompanied by southward growth of the Qilian Shan. A review of the literature reveals that this phase of tectonic deformation is widespread in the northeastern Tibetan Plateau and some recent studies suggest ~25–20 Ma onset of sediment accumulation in the northern Qaidam Basin bounding the Qilian Shan. These results challenge models arguing for early deformation of northeastern margin of the Tibetan Plateau. •We present apatite (U-Th)/He altitude transect ages from the southern Qilian Shan.•The data reveal rapid exhumation of the southern Qilian Shan during 15–10 Ma.•Regional deformation in the mid-late Miocene occurred in the NE Tibetan Plateau.