Northward subduction-related orogenesis of the southern Altaids:Constraints from structural and metamorphic analysis of the HP/UHP accretionary complex in Chinese southwestern Tianshan,NW China  

作　　者：Mark Scheltens Lifei Zhang Wenjiao Xiao Jinjiang Zhang 

机构地区：[1]School of Earth and Space Sciences, Peking University [2]State Key Laboratory of Lithosphere Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences

出　　处：《Geoscience Frontiers》2015年第2期191-209,共19页地学前缘（英文版）

基　　金：supported by the Chinese Major State Basic Research Program (Grants Nos.2009CB825007,2007CB411307);National Natural Science Foundation of China(Grant Nos.40730314,40821002, 41230207,41390441,41190075);the Molengraaff Fund to MCS

摘　　要：The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subduction polarity and the way of accretion are the main problems. Southward, northward subduction and multiple subduction models have been proposed. This study focuses on the structural geology of two of the main faults in the region, the South Tianshan Fault and the Nikolaev Line. The dip direction in the Muzhaerte valley is southward and lineations all point towards the NW. Two shear sense motions have been observed within both of these fault zones, a sinistral one, and a dextral one, the latter with an age of 236-251 Ma. Structural analyses on the fault zones show that subduction has been northward rather than southward. The two shear sense directions indicate that the Yili block was first dragged along towards the east due to the cloclkwise rotation of the Tarim block. After the Tarim block stopped rotating, the Yili block still kept going eastward, inducing the dextral shear senses within the fault zones.The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subduction polarity and the way of accretion are the main problems. Southward, northward subduction and multiple subduction models have been proposed. This study focuses on the structural geology of two of the main faults in the region, the South Tianshan Fault and the Nikolaev Line. The dip direction in the Muzhaerte valley is southward and lineations all point towards the NW. Two shear sense motions have been observed within both of these fault zones, a sinistral one, and a dextral one, the latter with an age of 236-251 Ma. Structural analyses on the fault zones show that subduction has been northward rather than southward. The two shear sense directions indicate that the Yili block was first dragged along towards the east due to the cloclkwise rotation of the Tarim block. After the Tarim block stopped rotating, the Yili block still kept going eastward, inducing the dextral shear senses within the fault zones.

关 键 词：Structural geology Tianshan Subduction polarity HP/UHP belt 

分 类 号：P542[天文地球—构造地质学]