Thrust Propagation in the Aqqikkol Lake Area, East Kunlun, Northwestern China

The western sector of the East Kunlun is one of the less studied regions in northwestern China. A structural analysis of the typical sections shows that, 1. There is a very well-developed fault system in the western sector of the East Kunlun, and thrust propagation, normal slip and decoupling were the main deformation events in the area; 2. Although thrusting in the area started in the Late Carboniferous and Late Triassic-Early Jurassic, strong activity took place in the Miocene-Quaternary when the Kumkol basin was strongly downwarped; and 3. The tectonic pattern of the coexistence of N-directed thrust propagation and S-directed normal slipping in the area is consistent with the general tectonic pattern of the northern Qinghai-Tibet plateau and also very similar to the tectonic pattern of the Himalaya region on the southern margin of the Qinghai-Tibet plateau, but, the directions of thrust propagation are opposite. All the strong thrust propagation occurred in the Mio-Pliocene to Quaternary, a period of strong collision of the Indian plate and Eurasian plate and abrupt uplift of the Qinghai-Tibet plateau. This oppositely directed thrust propagation and normal slipping reveal the kinematic characteristics of a symmetric propagation of deep-seated materials beneath the Qinghai-Tibet plateau toward the northern and southern sides, and gravitational sliding of superficial materials toward the interior of the plateau. Therefore, the establishment of the fault system in the area may provide an approach to the study of the deep process in the northern Qinghai-Tibet plateau and construction of a unified geodynamic model of the uplift of the Qinghai-Tibet plateau.