Extensional Setting of Hainan Island in Mesoproterozoic:Evidence from Granitic Intrusions in the Baoban Group

作     者：LIU Yuheng MAO Jingwen QIU Kunfeng HU Jun WANG Lei XU Deming LIU Yuheng;MAO Jingwen;QIU Kunfeng;HU Jun;WANG Lei;XU Deming

作者机构：MNR Key Laboratory of Geochemical ExplorationInstitute of Geophysical and Geochemical ExplorationChinese Academy of Geological SciencesLangfangHebei 065000China UNESCO International Centre on Global-scale GeochemistryLangfangHebei 065000China MNR Key Laboratory of Metallogeny and Mineral AssessmentInstitute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China China University of Geosciences(Beijing)Beijing 100083China State Key Laboratory of Geological Processes and Mineral ResourcesSchool of Earth Sciences and ResourcesChina University of Geosciences(Beijing)Beijing 100083China Frontiers Science Center for Deep Ocean Multispheres and Earth SystemKey Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine GeosciencesOcean University of ChinaQingdaoShandong 266100China Laboratory for Marine Mineral ResourcesQingdao National Laboratory for Marine Science and TechnologyQingdaoShandong 266237China Wuhan Center of China Geological Survey(Central South China Innovation Center for Geosciences)Wuhan 430205China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2022年第96卷第4期

页      面：1199-1212页

核心收录：

学科分类：070902[理学-地球化学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：funded by the Chinese Geological Survey Program(Grant Nos.DD20160035,DD20190047) the National Nonprofit Institute Research Grant of IGGE(AS2022P03) the Chinese Scholarship Council(File No.201606400032)Scholarship to Liu Yuheng 

主　　题：zircon U-Pb dating Lu-Hf isotopes granitic intrusions Baoban Group extensional setting Hainan Island 

摘      要：The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent *** Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia *** LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic *** with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic *** in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile *** zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental *** with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia *** the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during