Spatio-temporal variation in rock exhumation linked to large-scale shear zones in the southeastern Tibetan Plateau  

作　　者：Yukui GE Jing LIU-ZENG Jinyu ZHANG Wei WANG Yuntao TIAN Matthew FOX Lingsen ZENG Xiaoming SHEN Heng WANG Ze SU Kejia XIE 

机构地区：[1]State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China [2]Institute of Surface-Earth System Science,Tianjin UniversityTianjin 300072,China [3]Guangdong Provincial Key Laboratory of Geodynamics and Geohazards,School of Earth Sciences and Engineering,Sun Yat-sen University,Guangzhou 510275,China [4]Department of Earth Sciences,University College London,WC1E 6BT,UK [5]Key Laboratory of Deep-Earth Dynamics,Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [6]Key Laboratory of Crustal Dynamics,Institute of Crustal Dynamics,China Earthquake Administration,Beijing 100085,China [7]Henan Province Non-ferrous Metals Geological Mineral Resources Bureau,Zhengzhou 450016.China

出　　处：《Science China Earth Sciences》2020年第4期512-532,共21页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41761144065,41902213 and 41702223);the State Key Laboratory of Earthquake Dynamics of China(Grant No.LED2016A02);the National Key Research and Development Project of China(Grant No.2016YFC0600310);the Natural Environment Research Council of UK(Grant No.NE/N015479/1)。

摘　　要：Crustal-scale shear zones are believed to have played an important role in the tectonic and landscape evolution of orogens. However, the variation of long-term rock exhumation between the interior of shear zones and adjacent regions has not been documented in detail. In this study, we obtained new zircon U-Pb, biotite ^(40)Ar/^(39)Ar, zircon and apatite(U-Th)/He data, and conducted inverse thermal history modeling from two age-elevation profiles(the Pianma and Tu'er profiles) in the southeastern Tibetan Plateau. Our goal is to constrain the exhumation history of the Gaoligong and Chongshan shear zones and adjacent regions, so as to explore the effect of the shear zones on exhumation and their thermal effect on cooling that should not be ignored. Our results suggest that during the interval of 18–11 Ma the exhumation rates of rocks within the Gaoligong shear zone are anomalously high compared with those outside of. The rapid cooling during 18–11 Ma appears to be restricted to the shear zone, likely due to localized thermal effects of shearing and exhumation. After 11 Ma, both the areas within and outside of the shear zones experienced a similar two-stage exhumation history: slower cooling until the early Pliocene, and then a rapid increase in cooling rate since the early Pliocene. Our results indicate a synchronized exhumation but with spatially varied exhumation rates. Our study also highlights the important role of large-scale shear zones in exposing rocks, and thus the importance of the structural context when interpreting thermochronological data in the southeastern margin of the Tibetan Plateau.

关 键 词：Southeastern TIBETAN PLATEAU EXHUMATION (U-Th)/He LOW-TEMPERATURE THERMOCHRONOMETRY Shear zone 

分 类 号：P315[天文地球—地震学]