Ages and causes of steep slope relief between Tarim Basin and northwestern margin of the Tibetan Plateau:The evidence from apatite fission track dating of north margin of west Kunlun Mountains
Li Dunpeng1 Zhao Yue2 Liu Jiang2 Wan Jinglin3 Zheng Dewen3 Pan Yanbing2 He Zhefeng3
1.Zijin Mining College, Fuzhou University, Fuzhou 350108|2.Institute of Geomechanics, Chinese Academy of Geological Science, Beijing 100081|3.State Key Laboratory of Earthquake Dynamics,Institute of Geology, Chinese Earthquake Administration, Beijing 100029)
Tibetan Plateau，whose average elevation is more than 4 500 m，is joined the basin or plain whose elevation is less than 2 000 m through the steep slope relief of the edge of the Tibetan PlateauWhen，how does the steep slope relief formed？Nine Apatite fission track ages and length of the steep slope relief from the main thrust fault hanging wall in the middle of the northern margin of west Kunlun Mountains are analyzed in this paper，showed that fission track ages from the steep slope relief area of elevation 3 900～4 635 m are ranging from 6.2±1.4 Ma～0.9±0.3 Ma，fission track ages show as “up new under old” antiorder distribution. Thermal history modeling shows multistage uplifting and exhumation of～5 Ma，～3～2 Ma，～2～1 Ma and since～1 MaCombined with previous studies results and geological observations，think that steep slop relief what we now see in the northwestern margin of Tibetan Plateau is overstep propagation thrust results of west Kunlun thrust fault system since late Miocene，it experienced the multistage overstep propagation thrusting movement of～8 Ma，～5Ma，～3～2 Ma，～2～1 Ma and since～1 MaIt provides an important chronology constraints for age and causes of the steep slope relief forming in the margin of the Tibetan Plateau and uplifting of age and type of Tibetan Plateau.
. Ages and causes of steep slope relief between Tarim Basin and northwestern margin of the Tibetan Plateau:The evidence from apatite fission track dating of north margin of west Kunlun Mountains[J]. Chinese Journal of Geology, 2010, 45(04): 930-943.