藏北羌塘南部埃迪卡拉系达布热组的建立及其地质意义  

The establishment of Ediacaran Dabure Formation in southern Qiangtang of northern Tibet and its significance

作　　者：王明[1] 曾孝文[1] 李才[1] 李航 解超明[1] 范建军[1] WANG Ming;ZENG Xiaowen;LI Cai;LI Hang;XIE Chaoming;FAN Jianjun(College of Earth Sciences,Jilin University,Changchun 130061,Jilin,China)

机构地区：[1]吉林大学地球科学学院,吉林长春130061

出　　处：《地质通报》2018年第8期1379-1386,共8页Geological Bulletin of China

基　　金：国家自然科学基金项目<青藏高原羌塘南部埃迪卡拉纪地层研究>(批准号:41602230);<班公湖-怒江洋早白垩世演化:来自复理石沉积的制约>(批准号:41702227);中国地质调查局项目<班公湖-怒江成矿带铜多金属矿资源基地调查>(编号:DD20160026);<冈底斯-喜马拉雅铜矿资源基地调查>(编号:DD20160015)

摘　　要：羌塘位于青藏高原腹地,构造上处于冈瓦纳大陆北缘。因其特殊的构造位置,羌塘地体的起源及构造演化对于探讨青藏高原的早期形成演化、冈瓦纳大陆裂解,以及特提斯洋演化等关键科学问题至关重要。最近,在羌塘南部达布热地区发现一套碎屑岩夹玄武岩的岩石组合,碎屑岩具有低成分成熟度的特点,虽然岩石发生了低绿片岩相变质,但仍然保留了原岩类复理石沉积的特点。根据碎屑锆石定年结果,该套地层中碎屑锆石的最年轻年龄为550Ma左右。此外,该套地层中玄武岩夹层的测年结果表明,该套地层形成于埃迪卡拉纪(约550Ma)。结合地层剖面及区域地层对比,建立了埃迪卡拉纪达布热组。达布热组是羌塘地区首次发现的埃迪卡拉纪地层,该组地层的建立为探讨冈瓦纳大陆北缘构造演化提供了重要线索。The Qiangtang terrane is situated in the hinterland of the Tibetan Plateau on the northern margin of Gondwana.Because of its particular tectonic location,the understanding of the origin and tectonic evolution of the Qiangtang terrane is important in examining the formation and evolution of the Tibetan Plateau,the breakup of the Gondwana supercontinent,and the evolution of the Tethys Ocean.The Dabure clastic rocks discovered recently are characterized by low compositional and textural maturity,and have been affected by lower greenschist facies metamorphism.The deposits exhibit the typical features of turbidites.Based on detrital zircons U-Pb dating,the authors obtained the most reliable youngest age of detrital zircons from the Dabure clastic rocks,which is ca.550Ma.Combining the data obtained by the authors with previous work on the basalts in the Dabure area(the Dabure basalts),the authors tentatively suggest that the Dabure clastic rocks represent the late Ediacaran(ca.550Ma)sedimentary record of the Qiangtang terrane.On the basis of section measurement and regional correlation,the Ediacaran Dabure Formation was established.The establishment of the Dabure Formation not only has important theoretical significance for revealing the evolutionary history of the Qiangtang terrane in late Neoproterozoic but also provides new clues for tectonic evolution of the northeastern margin of Gondwana.

关 键 词：青藏高原 羌塘南部 碎屑岩 玄武岩 埃迪卡拉纪 

分 类 号：P534.3[天文地球—古生物学与地层学] P535[天文地球—地质学]