阿拉善地块南缘构造活动特征与青藏高原东北缘向外扩展的最新边界  

Tectonic Activity in the Southern Alashan Block and the Latest Boundary of Outward Expansion on the Northeastern Tibetan Plateau,China

作　　者：郑文俊 张博譞[1,2,3,4] 袁道阳 陈干 张逸鹏 俞晶星 张冬丽[1,2,3,4] 毕海芸 刘炳旭[1,2,3,4] 杨敬钧 ZHENG Wen-jun;ZHANG Bo-xuan;YUAN Dao-yang;CHEN Gan;ZHANG Yi-peng;YU Jing-xing;ZHANG Dong-li;BI Hai-yun;LIU Bing-xu;YANG Jing-jun(School of Earth Sciences and Engineering,Sun Yat-sen University,Guangzhou 510275,Guangdong,China;Guangdong Provincial Key Laboratory of Geodynamics and Geohazards,Sun Yat-sen University,Guangzhou 510275,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,Guangdong,China;State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;School of Earth Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]中山大学地球科学与工程学院,广东广州510275 [2]中山大学广东省地球动力作用与地质灾害重点实验室,广东广州510275 [3]南方海洋科学与工程广东省实验室(珠海),广东珠海519082 [4]中国地震局地质研究所地震动力学国家重点实验室,北京100029 [5]兰州大学地质科学与矿产资源学院,甘肃兰州730000

出　　处：《地球科学与环境学报》2021年第2期224-236,共13页Journal of Earth Sciences and Environment

基　　金：第二次青藏高原综合科学考察研究专题(2019QZKK0901);国家重点研发计划项目(2017YFC1500101);国家自然科学基金项目(41572197,41774049,41972228,41590861);广东省引进人才创新团队项目(2016ZT06N331)。

摘　　要：青藏高原向北东方向扩展的方式及最新扩展边界的位置,是目前青藏高原东北缘构造变形研究的热点。基于近年来对阿拉善地块南缘及邻区活动构造运动特征调查和定量研究结果,重点总结了阿拉善地块南缘活动断裂几何图像及运动特征,指出以前普遍认为的稳定阿拉善地块内部在新生代晚期发育了一系列规模不等、运动性质各异的活动断裂,这些活动断裂是青藏高原向外扩展过程中新生或先存断裂复活的结果,断裂对区域地貌的控制作用形成了阿拉善地块南缘的地貌和构造边界。综合新生代变形、构造地貌、低温年代学、大地测量与现代地震活动等资料和研究结果,认为青藏高原东北缘新生代中晚期以来发生了有序的向外扩展,形成了两个有重要意义的扩展边界:一是在10 Ma左右形成的以祁连山北缘断裂为主要边界控制构造的、完整清晰的青藏高原东北缘地貌及构造边界;二是在新生代晚期3~2 Ma形成的阿拉善地块南缘与祁连山北缘断裂近平行展布的、主要由逆冲断裂所组成的青藏高原扩展最新边界。在现今构造、地貌格局中,阿拉善地块南缘已成为青藏高原东北缘最新的组成部分。Recently,the most controversial and attractive issue in studying the tectonic deformation of the northeastern Tibetan Plateau is the way of northeastward expansion of Tibetan Plateau and the location of the latest active boundary of the northeastern Tibetan Plateau.Based on the investigation and quantitative research of active tectonics in the southern Alashan block and its adjacent regions,the geometry and kinematics of active faults located at the southern Alashan block were summarized.It is pointed out that Alashan block,which has been considered as a stable block,is actually composed of a set of active faults with different sizes and motion characteristics in the Late Cenozoic.These faults are either newly formed during the outward extension of the plateau or the results of reactivation of preexisting faults.The control of these faults on regional geomorphology leads to the geomorphological and tectonic boundary of the southern Alashan block.Combining the research results of Cenozoic deformation,tectonic geomorphology,low-temperature thermalchronology,geodesy and modern seismicity,it is proposed that the northeastern Tibetan Plateau has been expanding outward in a sequential way since the Late Cenozoic and forms two crucial boundaries.One is dominantly controlled by the North Qilian Shan fault since Late Miocene(10 Ma).The another is the latest active boundary which mainly consists of thrust faults located at the southern Alashan block paralleling to North Qilian Shan fault since Pliocene(3-2 Ma).In the present tectonic and geomorphic framework,the southern Alashan block has become the latest component of the northeastern Tibetan Plateau.

关 键 词：构造活动 几何图像 运动特征 构造转换 向外扩展 高原新边界 阿拉善地块南缘 青藏高原东北缘 

分 类 号：P546[天文地球—构造地质学]