The Jinhe-Qinghe fault鈥擜n inactive branch of the Xianshuihe-Xiaojiang fault zone, Eastern Tibet

详细信息	查看全文 | 推荐本文 |

• 作者：Wang Shifeng^a ; ^{wsf@itpcas.ac.cn} ; Jiang Guiguo^b ; Xu Tiande^c ; Tian Yuntao^d ; Zheng Dewen^e ; Fang Xiaomin^a
• 关键词：Xianshuihe&ndash ; Xiaojiang fault zone ; Longmen Shan thrust belt ; Jinhe&ndash ; Qinghe fault ; Offset ; Left-lateral strike slip
• 刊名：Tectonophysics
• 出版年：2012
• 期刊代码：82_00401951
• 类别：ear
• 出版时间：29 May, 2012
• 卷：544-545
• 期：Complete
• 页码：93-102
• 文件大小：4865 K

摘要

The Xianshuihe-Xiaojiang fault zone (XFZ) forms a prominent linear NW-SE trending tectonic feature along the southeastern margin of the Tibetan Plateau. The spatial and temporal evolution of the predominantly strike-slip movement along the fault remains unclear, as estimates for the initiation age of its different segments range from 5 to 13 Ma. The Jinhe-Qinghe fault (JqF; the south part of the Longmen Shan thrust belt) provides a key for understanding the tectonic role and deformation history of the Xianshuihe-Xiaojiang fault zone in terms of timing, magnitude of displacement, and spatial-temporal evolution. This paper presents research on the structure and chronology of the JqF. The results of a geometric and kinematic study of the Jinhe-Qinghe fault show it to be a thrust fault with a left-lateral strike slip component; The strike slip offset extends at least 13-18 km to southwest, based on the shortening of its folds and faulting, and based on stream deflection. Ten apatite fission track apparent ages show a pronounced change in age/elevation gradient at ~ 17 卤 2 Ma, consistent with an abrupt increase of exhumation due to uplift of the hanging wall of the JqF at that time. Combined with the age of deformed Tertiary strata in the footwall of the JqF and the geometric relationships of the JqF with the Chenghai fault and the XFZ, this indicates that the JqF was active between 17 and 5 Ma. Based on the fault chronology, geometry, and movement, we suggest that the fault was a transpressional structure at the south end of the XFZ during the period from 17 to 5 Ma.