阿尔金断裂南侧弧形地貌单元成因及其构造意义  

THE MECHANISMS OF ARCUATE STRUCTURES ON THE SOUTH SIDE OF THE ALTYN TAGH FAULT AND THEIR TECTONIC IMPLICATIONS

作　　者：栗兵帅 颜茂都[2,3] 张伟林[2,3] 杨永鹏 张大文 陈毅 关冲 LI Bing-shuai;YAN Mao-du;ZHANG Wei-lin;YANG Yong-peng;ZHANG Da-wen;CHEN Yi;GUAN Chong(State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China;Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Beijing 100101, China;Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China;China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing 100083, China;Zaozhuang University, Zaozhuang 277160, China;State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,南昌330013 [2]中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京100101 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101 [4]中国自然资源航空物探遥感中心,北京100083 [5]枣庄学院,枣庄277160 [6]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [7]中国科学院大学,北京100049

出　　处：《地震地质》2019年第2期300-319,共20页Seismology and Geology

基　　金：国家重点研发计划(2017YFC0602803);中国科学院战略性先导科技专项(XDA20070201);中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室开放课题(LCPU201903)共同资助;第二次青藏高原综合科学考察研究项目;国家自然科学基金(41804065;41272185;41672358;41620104002);东华理工大学博士启动项目(DHBK2018013)

摘　　要：巨型左旋走滑的阿尔金断裂是青藏高原的北部边界,在印度-欧亚板块碰撞过程中起重要的调节作用,控制着青藏高原东北部的构造演化,认识其活动演化对理解青藏高原的构造变形过程和机制具有重要意义。阿尔金断裂南侧存在一系列弧形地貌单元,知晓这些弧形带是原始弧形弯曲还是后期由于阿尔金断裂左旋走滑拖曳而形成的,对认识阿尔金断裂的构造演化具有重要意义。文中在前期阿尔金断裂南侧柴西英雄岭和柴北缘2条弧形带不同部位已开展的精细古地磁旋转变形研究的基础上,综合研究区和阿尔金断裂附近已有的古地磁旋转变形研究结果和弧形带几何形态学等其它地质证据,分析发现这2条弧形带的几何学特征是由其不同部位发生旋转变形所导致的,且旋转变形与该时段阿尔金断裂的快速左旋走滑活动密切相关。通过上述工作,更加全面地了解了阿尔金断裂新生代2阶段的走滑特征,进一步限定了阿尔金断裂早渐新世以来左旋滑移量,以柴西段为参照系滑移量至少约350～430km,以柴北缘段为参照系至少约380～460km,平均滑移速率至少约10. 6～13. 9mm/a。The giant sinistral Altyn Tagh Fault(ATF) is the northern boundary of the Tibetan Plateau. It has been playing important role in adjusting the India-Eurasia collision and the tectonic evolution of the northeastern Tibetan Plateau. Knowledge of the evolution of the ATF can provide comprehensive understanding of the processes and mechanisms of the deformation of the Tibetan Plateau. However,its timing of commencement,amount of displacement and strike-slip rate,as well as the tectonic evolution of the region are still under debate. South of the ATF,there exist a series of oroclinal-like arcuate structures. Knowledge of whether these curved geometries represent original curvatures or the bending of originally straight/aligned geological units has significant tectonic implications for the evolution of the ATF. The Yingxiongling arcuate belt in the western Qaidam Basin and the northern Qaidam marginal thrust belt(NQMTB) north of the Qaidam Basin are the two typical arcuate thrust belts,where the former has a "7-types"structure,and the latter has a reverse "S-type"structure.Successive Cenozoic sediments are well exposed and magnetostratigraphically dated in both belts.Paleomagnetic declination has great advantage to reveal vertical-axis rotations of geological bodies since they become magnetized. Recently conducted paleomagnetic rotation studies in different parts of these two thrust belts revealed detailed Cenozoic rotation patterns and magnitudes of the region. By integrating these paleomagnetic rotation results with regional geometric features and lines of geological evidence,we propose that these two arcuate thrust belts were most likely caused by different rotations in different parts of these curvatures,due to the sinistral strike-slip faulting along the ATF,rather than originally curved ones. The Yingxiongling arcuate belt was shaped by the significant counterclockwise(CCW) rotations of its northwestern half(the Akatengnengshan anticline) near the ATF during ~ 16 ~ 11 Ma BP,while its southeastern half(the Youshas

关 键 词：阿尔金断裂 弧形带 柴北缘 英雄岭 古地磁旋转变形 

分 类 号：P931.2[天文地球—自然地理学]