The Mid-Miocene tectonic uplift of southern Qilianshan：Sedimentary evidence from Dahonggou section in Qaidam Basin
Lu Haijian1, Wang Erchie2, Meng Kai2
1. State Key Laboratory of Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037;
2. Tethys Research Center, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029
The clastic sediments in intermontane basins record typically a wealth of information on uplift of adjacent mountains. This study conducted detailed analyses of detrital content of sandstones for the Dahonggou section in north-central Qaidam Basin. The results indicate that the provenance area of the Dahonggou section did not change in nature from 34 Ma to 8.5 Ma and was foreland uplift provenance. However, the values of quarts, feldspar and lithic fragments in sandstones collectively displayed two-stage evolution characteristics and varied significantly at 12 Ma. Those observations are consistent with that obtained by sedimentology, sedimentation rate, and magnetic susceptibility analyses. Presumably, it was very likely associated with the tectonic reactivation of northern Qaidam thrust belts north of Dahonggou section at 12 Ma.