Exhumation and Deformation of the Daba Shan Orocline as Determined from Modern River Sands Apatite Fission-Track  

作　　者：Jiali You Zhao Yang Xiaohui Shi Chuanbo Shen Yunpeng Dong Bin Cheng 

机构地区：[1]State Key Laboratory of Continental Dynamics,Northwest University,Xi'an 710069,China [2]Key Laboratory of Tectonics and Petroleum Resources,China University of Geosciences,Wuhan 430074,China

出　　处：《Journal of Earth Science》2023年第4期1140-1149,共10页地球科学学刊（英文版）

基　　金：funded by the National Natural Science Foundation of China (Nos.42172257,41672199,41421002);MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest University;the Foundation of Shaanxi Educational Committee (No.16JK1753)。

摘　　要：The Daba Shan orocline is located at the northeastern margin of the Sichuan Basin and has been inferred as a foreland thrust-fold belt of the Qinling Orogen since the Late Triassic.A complete understanding of rock exhumation history is critical to elucidate how and when this typical orocline structure is developed.Detrital apatite fission-track dating of modern river sands is employed to reveal the regional exhumation history of the Daba Shan orocline.Four age peaks are identified and interpreted as the results of tectonic exhumation.Two older age peaks at ~150–140 and ~116–86 Ma are agreement with two main shortening deformation episodes of the Yanshanian Movement in the eastern China.The other two younger age peaks at ~69 and ~37 Ma support that the Daba Shan was reactivated by the Late Cretaceous to Cenozoic deformation which were likely related to the subduction of the Pacific Ocean and eastward growth of the Tibetan Plateau,respectively.It is worth noting that in contrast to the ~150–140 Ma rapid rock uplift and exhumation,the Middle Cretaceous exhumation(~116–86 Ma) shifted southward and continued to spread to southern tips of the Daba Shan.These exhumation variations in temporal and spatial allow a southward thrust deformation with piggyback style during the Yanshanian.

关 键 词：detrital thermochronology APATITE fission-track dating exhumation history Daba Shan orocline. 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]