龙木错-双湖-昌宁-孟连结合带:冈瓦纳大陆与泛华夏大陆的界线  

Longmu Co-Shuanghu-Changning-Menglian suture zone:The boundary between Gondwanaland and Pan-Cathaysia mainland in the Qinghai-Tibet Plateau

作　　者：王保弟 王立全[2,3] 周道卿[1] 王冬兵 于云鹏[1] 闫国川 吴喆 WANG Baodi;WANG Liquan;ZHOU Daoqing;WANG Dongbing;YU Yunpeng;YAN Guochuan;WU Zhe(China Aero Geophysical Survey and Remote Sensing Center for Natural Resources,Beijing 100083,China;Chengdu Center,China Geological Survey,Chengdu 610081,Sichuan,China;Research Center for Tibetan Plateau Geology,China Geological Survey,Chengdu 610081,Sichuan,China;Graduate School of Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国自然资源航空物探遥感中心,北京100083 [2]中国地质调查局成都地质调查中心,四川成都610081 [3]中国地质调查局青藏高原地质研究中心,四川成都610081 [4]中国地质科学院研究生院,北京100037

出　　处：《地质通报》2021年第11期1783-1798,共16页Geological Bulletin of China

基　　金：国家自然科学基金项目《羌塘中部泥盆纪—石炭纪岩浆作用对古特提斯洋构造演化的制约》(批准号:41773026);第二次青藏高原综合科学考察研究项目《典型地区岩石圈组成、演化与深部过程》(编号:2019QZKK0702)。

摘　　要：冈瓦纳大陆与泛华夏大陆的界线目前还没有形成统一的认识,在一定程度上制约了对青藏高原及三江造山带构造格局、特提斯演化等方面的深刻认识。根据新的地质调查资料与研究成果,在梳理有关冈瓦纳大陆与泛华夏大陆界线不同观点的基础上,系统总结了龙木错-双湖结合带与昌宁-孟连结合带不同时期蛇绿混杂岩的地质特征、发育时限及其构造环境,二者洋盆经历了相似的洋盆扩张、俯冲消减及弧-弧(陆)碰撞造山过程,发生深俯冲及折返的时间也基本相当,一致表明二者在构造属性上具有亲缘性,认为龙木错-双湖-昌宁-孟连特提斯洋共同构成了原-古特提斯大洋最终消亡后的残迹。南、北羌塘地块基底具有不同的航磁异常,指示龙木错-双湖特提斯洋两侧陆块演化过程不同。以龙木错-双湖-昌宁-孟连特提斯洋为界,南北分别为冈瓦纳大陆北缘中生代冈底斯-喜马拉雅造山系和泛华夏大陆南缘晚古生代羌塘-三江造山系,两大造山系经历了不同的构造演化过程。结合生物区系、地球物理等其他区域资料,认为龙木错-双湖-昌宁-孟连结合带是青藏高原上冈瓦纳大陆与泛华夏大陆的界线。The boundary between Gondwanaland and Pan-Cathaysia mainland has not yet come to a consensus,which restricts the understanding of the tectonic patterns of Tibetan Plateau and Sanjiang Orogenic Belt,and the evolution of the Tethys Ocean.On the basis of sorting out different viewpoints,combined with new geological survey data and research results,the geological characteristics,development time limit and tectonic setting of ophiolitic mélange in different periods in the Longmu Co-Shuanghu suture zone and Changning-Menglian suture zone were systematically summarized.The Longmu Co-Shuanghu and Changning-Menglian ocean basins have experienced similar processes of ocean basin expansion,subduction and arc-arc(continent)collision orogeniy,and basically have the same deep subduction and orogenic time,indicating that they have affinity in tectonic attributes.It is believed that Longmu Co-Shuanghu-Changning-Menglian Tethys oceans together constitute the remnants of the Proto-Paleo Tethys Ocean after its final extinction.The basement of the south and north Qiangtang blocks have different aeromagnetic anomalies on both sides of the Longmu Co-Shuanghu Tethys Ocean,indicating that the evolution process of the blocks is different.Bounded by the Longmu Co-Shuanghu-Changning-Menglian Tethys oceans,the south block is Mesozoic Gangdese-Himalayan orogenic system on the northern margin of Gondwanaland,and the north block is Late Paleozoic Qiangtang-Sanjiang orogenic system on the southern margin of Pan-Cathaysia mainland.The two orogenic systems have undergone different tectonic evolution processes.Combined with other regional data such as biota and geophysics,it is suggested that the Longmu Co-Shuanghu-Changning-Menglian suture zone is the boundary between Gondwanaland and Pan-Cathaysia mainland in the Tibetan Plateau.

关 键 词：龙木错-双湖结合带 昌宁-孟连结合带 特提斯洋 高压-超高压变质带 冈瓦纳大陆 泛华夏大陆 

分 类 号：P542[天文地球—构造地质学]