海南岛抱板岩群的形成时代及其大地构造意义  

The Formation Age of Baoban Group in Hainan Island and its Tectonic Significance

作　　者：龙文国 王晶[1] 谭满堂 田洋 金巍[1,2] 杨博 童喜润[1,2] 周进波 LONG Wen-Guo;WANG Jing;TAN Man-Tang;TIAN Yang;JIN Wei;YANG Bo;TONG Xi-Run;ZHOU Jin-Bo(Wuhan Center,China Geological Survey(Geosciences Innovation Center of Central South China),Wuhan 430205,Hubei,China;Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey,Wuhan 430205,Hubei,China;Hainan Geological Survey,Haikou 570206,Hainan,China)

机构地区：[1]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205 [3]海南省地质调查院,海南海口570206

出　　处：《华南地质》2024年第2期270-285,共16页South China Geology

基　　金：中国地质调查局地质调查项目(DD20230226,DD12120113066400,DD20160031,DD20240065,DD20243446)。

摘　　要：抱板岩群(原称抱板群)是目前海南岛发现的最古老的前寒武纪结晶基底,经历了多期构造热事件的改造,是研究海南(海南岛)地块大地构造属性及块体划分的重要载体。在总结前人已有研究成果的基础上,本文对海南岛东方市抱板地区抱板岩群混合岩及后期侵入的花岗岩、基性岩开展了SHRIMP和LA-ICP-MS锆石U-Pb年代学研究,厘定了抱板杂岩的形成时代、经历的构造热事件,并探讨其所代表的大地构造意义。根据岩石组合特征,本文将抱板岩群进一步划分为戈枕村岩组和峨文岭岩组,二者均被晚期花岗质和基性岩浆侵入,它们一起构成了抱板杂岩。锆石年代学结果表明:戈枕村岩组形成时代应介于1480~1440 Ma之间,峨文岭岩组形成时代介于1460~1430 Ma之间,片麻状花岗岩侵入时代为1450~1430 Ma,基性岩侵入时代为1425~1410 Ma。抱板岩群在中元古代早中期经历了花岗岩侵入、混合岩化作用、基性岩侵入等多期构造热事件的改造,中元古代晚期-新元古代早期经历了与罗迪尼亚超大陆汇聚有关的构造热事件。区域上块体对比分析表明,海南地块与越南昆嵩地块具有相似的前寒武纪结晶基底组成及多期构造热事件记录,显示二者具有亲缘关系。The Baoban Group is the oldest Precambrian crystalline basement discovered on Hainan Island to date,having undergone multiple tectonothermal events,making it an important carrier for studying the geotectonic attributes and block division of the Hainan(Hainan Island) Block.On the basis of summarizing the previous research results,this paper conducts a new study on the zircon U-Pb geochronology through SHRIMP and LA-ICP-MS of migmatite and later intrusive granites and mafic rocks in the Baoban Group in the Baoban area of Dongfang city,Hainan Island to determine the formation age of the Baoban complex,the tectonothermal events it has undergone,and its tectonic significance.According to the characteristics of rock combinations,the Baoban Group can be further divided into the Gezhencun Formation and the Ewenling Formation,both of which are intruded by later granitic and basic magmas and together constitute the Baoban complex.Zircon geochronology results indicate that the Gezhencun Formation was formed between 1480 ~ 1440 Ma,the Ewenling Formation was formed between 1460 ~ 1430 Ma,the gneissic granite intrusion occurred between 1450 ~ 1430 Ma,and the mafic intruded later between 1425 ~ 1410 Ma.During the early to middle Mesoproterozoic,it underwent multiple tectono-thermal events including granite intrusion,migmatite,and mafic rock intrusion,while in the late Mesoproterozoic to early Neoproterozoic,it experienced tectono-thermal events related to the convergence on the Rodinia supercontinent.Regional block comparison analysis shows that the Hainan Block shares a similar Precambrian crystalline basement composition and multiple tectono-thermal event records with the Kontum Block of Vietnam,indicating an obvious affinity between them.

关 键 词：抱板岩群 中元古代 前寒武纪 结晶基底 锆石 海南地块 

分 类 号：P56[天文地球—构造地质学]