祁连造山带构造演化与新生代变形历史  

Tectonic evolution and Cenozoic deformation history of the Qilian orogen

作　　者：吴晨 陈宣华 丁林[1] WU Chen;CHEN Xuanhua;DING Lin(State Key Laboratory of Tibetan Plateau Earth System,Environment and Resources(TPESER),Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;SinoProbe Center,Chinese Academy of Geological Sciences and China Geological Survey,Beijing 100037,China)

机构地区：[1]中国科学院青藏高原研究所青藏高原地球系统与资源环境全国重点实验室,北京100101 [2]中国地质调查局、中国地质科学院地球深部探测中心,北京100037

出　　处：《地学前缘》2023年第3期262-281,共20页Earth Science Frontiers

基　　金：科学技术部第二次青藏高原综合考察研究项目(2019QZKK0708);国家自然科学基金委基础科学中心项目(41988101-01);青年基金项目(41702232)

摘　　要：祁连造山带位于东特提斯北缘,蛇绿混杂岩带、(超)高压变质岩和弧岩浆岩等广泛发育,是前新生代华北克拉通与柴达木古地块之间多期次俯冲、碰撞和造山形成的复合造山带。现今的祁连山是青藏高原北缘高原隆升与扩展的关键构造带,具有复杂的陆内变形构造和深部结构,记录了新生代高原生长过程中不同阶段的构造变形和盆山演化历史。本文在区域地质研究资料的综合分析基础上,讨论祁连造山带元古宙变质基底属性、新元古代—古生代古海洋演化和中—新生代构造变形特征,探讨祁连(山)造山带的构造演化过程和陆内变形历史。祁连造山带发育新元古代早期和早古生代两期岩浆弧,分别代表了古祁连洋和(南、北)祁连洋的俯冲碰撞事件;亲华北的基底属性指示了祁连洋实属陆缘海。新生代青藏高原东北缘发育两阶段构造变形和盆山演化,在中新世完成了由新生代早期以逆冲断裂活动为主向走滑断裂和逆冲断裂共同作用的转变,随着东昆仑山的快速隆起将古近纪大盆地隔开成两个盆地,即现今的柴达木盆地和可可西里盆地。中新世中晚期以来,青藏高原东北缘的构造格局主要受控于东昆仑和海原两个近乎平行的大型转换挤压构造系统的发育、顺时针旋转和侧向生长。大型走滑断裂系统在造山带内的生长过程与发育机制是陆内变形研究的中心问题,需要进一步的定量化研究。The Qilian orogen—formed along the northern margin of the eastern Tethys as results of pre-Cenozoic multi-phase subduction,continental collision and punctuated orogeny involving the North China craton and the Qaidam paleocontinent—develops widespread ophiolitic mélange belts and(ultra-)high pressure metamorphic and arc igneous rocks.The present Qilian Mountains,a key tectonic zone undergoing plateau uplift/expansion along the northern margin of the Tibetan Plateau,with complex intracontinental deformation and deep structures,records the histories of tectonic deformation and basin-mountain evolution during different stages of plateau growth in the Cenozoic.This paper,on the basis of comprehensive analysis of regional geological data,discusses the nature of Proterozoic metamorphic basement,paleo-oceanic evolution during the Neoproterozoic-Paleozoic,and Mesozoic-Cenozoic structural deformation,and explores the tectonic evolution of the Qilian orogen and the intracontinental deformation history of the Qilian Mountains.The Early-Neoproterozoic and Early-Paleozoic arcs represent respectively subduction-collision events took place in the Paleo-Qilian and(South/North)Qilian oceans.Basement structure beneath the North China craton suggests that the Qilian ocean is not the ocean separating the Gondwana and Laurasia continents,but rather a relatively small embayed sea along the southern margin of the Laurasia continent.The northeastern margin of the Tibetan Plateau experienced two-stage tectonic deformation and basin-mountain evolution in the Cenozoic,while transition from Early-Cenozoic thrust activity to joint action of strike-slip/thrust faults occurred in the Miocene,where,with rapid uplift of the Eastern Kunlun Range,a large Paleogene basin split into two basins—the current Qaidam Basin and the Hoh Xil Basin.Since the Middle-Late Miocene the tectonic framework along the margin has been mainly controlled by the development and clockwise rotation/lateral growth of two large near-parallel transpressional tectonic s

关 键 词：青藏高原 祁连造山带 构造演化 构造变形 高原生长 盆山演化 

分 类 号：P548[天文地球—构造地质学]