西藏中部羌塘地体白垩纪以来隆升剥露过程  

The uplift and exhumation processes in the Qiangtang terrane of Central Tibet since the Cretaceous

作　　者：毕文军 张佳伟 李亚林[3] 邓玉珍 BI Wenjun;ZHANG Jiawei;LI Yalin;DENG Yuzhen(Department of Earth Sciences and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Beijing),Beijing 100083,China;Shanxi Museum of Geology,Taiyuan 030000,China)

机构地区：[1]太原理工大学地球科学与工程系,山西太原030024 [2]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 [3]中国地质大学(北京)生物地质与环境地质国家重点实验室,北京100083 [4]山西地质博物馆,山西太原030000

出　　处：《地学前缘》2023年第2期18-34,共17页Earth Science Frontiers

基　　金：中国地震局地质研究所基本科研业务专项(IGCEA2225);山西省自然科学基金青年项目(202103021223120);科学技术部第二次青藏高原科学考察项目(2019QZKK0803)。

摘　　要：青藏高原的隆升直接影响了区域乃至全球的气候变化,其地貌演化过程存在较大争议。羌塘地体作为青藏高原的重要组成部分,了解其隆升和剥露过程对于认识高原中部的地貌演化具有重要意义。已发表的构造变形和低温热年代数据显示,羌塘地体地表隆升和剥露过程经历了早白垩世—古新世(125~65 Ma)、始新世(55~35 Ma)以及渐新世以来(<30~0 Ma)3个阶段。在白垩纪—古新世时期,拉萨-羌塘地体的碰撞以及中羌塘地体的构造负载导致逆冲断层和地表剥露从中羌塘地体向南、北扩展到南、北羌塘地体。在始新世时期,印度-亚洲板块连续汇聚引起拉萨地体和松潘-甘孜地体分别向北、南俯冲,导致南羌塘地体和北羌塘地体北缘强烈变形和剥露,而中羌塘地体和北羌塘地体中部微弱变形和剥露。此时,该地体的海拔至少达到了3.0~4.0 km。在渐新世以来,羌塘地体构造变形已经结束,地表剥露可能与该地体南北向正断层活动有关。The Tibetan Plateau uplift resulted in regional and global climate changes;however, the geomorphic evolution of the Tibetan Plateau is still in dispute. As a significant part of the Tibetan Plateau, the Qiangtang terrane plays an important role in understanding the geomorphic evolution of Central Tibet. The published structural deformation and low-temperature thermochronological data showed that the uplift and exhumation of the Qiangtang terrane experienced three main phases: Early Cretaceous-Paleocene(120-65 Ma), Eocene(55-35 Ma), and Post-Oligocene(<30-0 Ma). During the Early Cretaceous-Paleocene, the Lhasa-Qiangtang collision and the tectonic load of the Central Qiangtang terrane led to outward-propagating deformation and exhumation originated from the Central Qiangtang terrane. During the Eocene, northward and southward subductions of the Lhasa and Songpan-Ganzi terranes, respectively, driven by continued convergence between the Indian and Asian plates, resulted in intensive deformation and exhumation of the Southern Qiangtang terrane and the northern edge of the North Qiangtang terrane, but little erosion and deformation in the Central Qiangtang terrane and central zone of the North Qiangtang terrane. The Qiangtang terrane had attained an elevation of 3-4 km by ~35 Ma. Since the Oligocene structural deformation in the Qiangtang terrane has ceased, where surface exhumation may be related to N-S trending normal fault activity in the region.

关 键 词：羌塘地体 隆升和剥露历史 低温热年代 构造变形 

分 类 号：P542[天文地球—构造地质学] P12.2[天文地球—地质学] P597.3