Early Cretaceous Thrust and Nappe Tectonics in North Qilian Shan,Northern Tibetan Plateau:Evidence from Field Mapping,Geochronology,and Deep Structural Analysis  

作　　者：HAN Lele DING Weicui CHEN Xuanhua SHAO Zhaogang ZHANG Da XIAO Yongjun HE Chengguang WANG Zengzhen LI Bing ZHANG Yiping XU Shenglin WANG Ye 

机构地区：[1]School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China [2]SinoProbe Center,Chinese Academy of Geological Sciences and China Geological Survey,Beijing 100037,China [3]Exploration and Development Research Institute,Shengli Oilfield Company,Sinopec,Dongying,Shandong 257000,China [4]Henan Institute of Geological Survey,Zhengzhou,Henan 450001,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第4期1058-1077,共20页地质学报（英文版）

基　　金：financially supported by the China Geological Survey(Grant Nos.DD20230229,DD20160083,DD20190011,DD20221643-5);the National Key Research and Development Program of China(the DREAM—Deep Resource Exploration and Advanced Mining;Grant No.2018YFC0603701);the Cooperative Project between the Chinese Academy of Geological Sciences and the Sinopec Shengli Oilfield Company(Grant No.P22065)。

摘　　要：The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies emphasize the Cenozoic deformation due to the far-field response to the Indo-Asian collision,but the Mesozoic deformations are poorly constrained in this area.We conducted detailed field mapping,structural analysis,geochronology,and structural interpretation of deep seismic reflectional profiling and magnetotelluric(MT)sounding,to address the superposed results of the Mesozoic and Cenozoic deformation.The results recognized the North Qilian thrust and nappe system(NQTS),the root and the frontal belt are the North Qilian thrust(NQT),and the Yumu Shan klippe(YK),respectively.The middle belt is located between the NQT and the YK.Monzonitic granite zircon U-Pb dating from the middle belt yields an age of ca.415 Ma,which is similar to south NQT.The thrusting displacement is estimated at ca.48 km by structural interpretation of deep profiles.The timing is constrained in the early stage of the Early Cretaceous by the formation of simultaneous growth strata.We suggest that the NQTS has resulted from the far-field effect of the Lhasa-Qiangtang collision,and the Yumu Shan is uplifted by the superposed Cenozoic deformation.

关 键 词：GEOCHRONOLOGY structural analysis seismic reflectional and MT profiling Early Cretaceous North Qilian thrust and nappe system Tibetan Plateau 

分 类 号：P534.53[天文地球—古生物学与地层学]