The latest carboniferous through Permian orogenic processes of Chinese Tianshan mountains: Evidence from structural deformation and Ar-Ar geochronology

Tianshan in the central Asia is a huge WE-extended mountain on the Earth with about 4000km length from west Uzbekistan eastwards through central Xinjiang province of NW China to the southwestern Mongolia. Available data reveal that the occurrence of mountains is originated from uplift and re-deformation of Paleozoic accretion-collisional orogens during Cenozoic, which is considered as the far-effect of the collision between Indian and Eurasian plates. The Paleozoic orogens was result of the convergence and closure of Pale-Asian ocean. However, closure timing of the ocean and geological processes of orogens have been hot-debated issues in the geological field. Based on geological investigations in last 20 years, the author find out that there are three periods of structural deformations in the latest Carboniferous through Permian geological history, they are, in turn, the latest Carboniferous ( ~300Ma) compressional deformation, Early Permian (280~290Ma) extensional deformation, and Late Pemian (~260Ma) strike-slip deformation. These structural events may be originated from collisional orogeny, post-collisional delamilation and mantle-magma platting, and accretional processes in the southern margin of the Eurasian plate. This research is financially supported by the National Key Basic Research Program of China (granted No. 2007CB411306, 2001CB409810), and Surveying and Investigating Project of Land and Resources of China (grant No. 1212010611806, 1212010711817).