琼西抱板杂岩中伟晶岩年代学及其地质意义  

Geochronology of pegmatite in the Baoban complex in the western Hainan and its geological significance

作　　者：恽虎 王成[2] 官军 费光春[1,3] YUN Hu;WANG Cheng;GUAN Jun;FEI Guang-chun(Hainan Key Laboratory of Marine Geological Resources and Environment,Haikou 570206,Hainan,China;Hainan Geological Survey Institute,Haikou 570206,China;College of Earth and Planetary Science,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]海南省海洋地质资源与环境重点实验室,海口570206 [2]海南省地质调查院,海口570206 [3]成都理工大学地球与行星科学学院,成都610059

出　　处：《矿物岩石地球化学通报》2024年第5期973-986,共14页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：海南省海洋地质资源与环境重点实验室开放课题(22-HNHYDZZYHJKF021)。

摘　　要：为厘清海南岛西部抱板杂岩中伟晶岩的形成时代,揭示伟晶岩与抱板杂岩之间的成因联系,示踪海南岛构造演化过程,在地质特征研究基础上,对抱板杂岩中的伟晶岩开展了独居石和磷钇矿LA-ICP-MS U-Pb年代学研究。结果表明,侵入戈枕村组中的伟晶岩(HPGZ-11)中的磷钇矿^(206)Pb/^(238)U加权平均年龄为(351.3±1.8)Ma,侵入中元古代片麻状花岗岩的伟晶岩(HPGZ-21)中的独居石^(208)Pb/^(232)Th加权平均年龄为(432.6±1.3)Ma。综合前人研究资料和本次研究成果,认为抱板杂岩中伟晶岩HPGZ-21及HPGZ-11分别形成于志留纪和石炭纪,而不是以往认为的抱板期(中元古代),其形成可能分别与海南岛加里东运动和中晚泥盆世-石炭纪持续裂解事件有关。In order to clarify the formation age of pegmatite in the Baoban complex in the western Hainan,to reveal the genetic relationship between the pegmatite and the Baoban complex,as well as to trace the tectonic evolution of Hainan Island,in this study,based on the study of geological characteristics of the pegmatite,the LA-ICP-MS U-Pb geochronological study of monazite and xenotime from the pegmatite has been carried out.The results show that the ^(206)pb/^(238)U weighted mean age of xenotime from the pegmatite(HPGZ-11)intruded into the Gezhencun Formation was(351.3±1.8)Ma.The ^(208)pb/^(232)Th weighted mean age of monazite form the pegmatite(HPGZ-21)intruded into the Proterozoic gneissic granite was(432.6±1.3)Ma.Based on the previous research data and the results of this study,it is believed that the HPGZ-21 and HPGZ-11 pegmatites were formed in the Silurian and Carboniferous periods,respectively,rather than the previously believed Mesoproterozoic,and their formation may be respectively related to Caledonian movement and the continuous rifting event from the Middle-Late Devonian to Carboniferous in Hainan Island.

关 键 词：独居石 磷钇矿 U-PB年代学 伟晶岩 抱板杂岩 海南岛 

分 类 号：P597[天文地球—地球化学]