MECHANICS MODEL OF PROGRESSIVE UPLIFT OF QINGHAI-TIBET PLATEAU
MA Runyong, XI Xianwu, PENG Jianbing, ZHAO Fasuo and LI Xi'an (College of Geological Engineering and Geometry, Chang’an University,Xi’an, SX 710054, China)
On the basis of GPS velocity field of contemporary tectonic deformation, geometric correlation between Mt. Himalaya, Gangdese-Nyainqentanglha Range, Tanggula Shan, Kunlun Shan and Qilian Shan, morphostructure features of these mountains and layered structures of lithosphere in Qinghai-Tibet Plateau, a new point of view has been put forward, holding that the uplift of Qinghai-Tibet Plateau is progressive under the Indian Plate, which serves to push Qinghai-Xizang Plate northwards. Based on this cognition, the mechanics model of progressive bending and uplifting of crust has been established. Based on approximate plane strain conditions and by using the finite difference numerical analysis software - FLAC-2D, the process of sequential compressing, bending, folding and uplifting of crust under horizontal force was simulated. The result suggests that the main power-source for the plateau uplift is the driving and compressing of Indian plate toward NNE, and, a series of folding and uplifting of the crust successively appears from the south to the north, demonstrating a kind of sequence and consequence on the plane and section of Qinghai-Tibet Plateau. The uplift of Qinghai-Tibet Plateau resulted from the development and distribution of active tectonic zones.