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

Qingquan Meng (1) , Chunhui Song (2) , Junsheng Nie (2) , Chuan Liu (3) , Pengju He (2) , Fangbin Liu (2) , Lin Li (4)

1 School of Earth Science & Key Laboratory of Mineral Resources in Western China
2 Lanzhou University
3 Southwest University [Chongqing]
4 GR - Géosciences Rennes

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.

Keywords: (U-Th)/He thermochronology; Qilian Shan; Tibetan Plateau; Cenozoic; Rapid exhumation

Domains: Tectonics

Qingquan Meng, Chunhui Song, Junsheng Nie, Chuan Liu, Pengju He, et al.. Middle-late Miocene rapid exhumation of the southern Qilian Shan and implications for propagation of the Tibetan Plateau. Tectonophysics, 2020, 774, pp.228279. ⟨10.1016/j.tecto.2019.228279⟩. ⟨insu-02371699⟩