海南五指山地区花岗片麻岩锆石LA-ICP-MS U-Pb年代学特征及其地质意义  

Zircon LA-ICP-MS U-Pb dating of granitic gneisses from Wuzhishan area,Hainan,and geological significances

作　　者：陈新跃[1,2] 王岳军[2] 范蔚茗[2] 张菲菲[2] 彭头平[2] 张玉芝[2] 

机构地区：[1]湖南科技大学地质研究所,湖南湘潭411201 [2]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地球化学》2011年第5期454-463,共10页Geochimica

基　　金：国家自然科学基金(40902062;40825009;40830319);国家重点基础研究发展计划项目(2007CB411403);高等学校特色专业建设点项目(TS11027)

摘　　要：海南五指山地区出露大面积花岗片麻岩,且广泛发育NW向定向变形构造,表明经历了明显的动力变形变质作用;4个花岗片麻岩样品的LA-ICP-MS锆石U-Pb年代学测试数据表明它们形成于263～269 Ma,代表了中二叠世的一次重要地质构造热事件。结合前人研究成果认为,海南五指山地区263～269 Ma花岗片麻岩可能形成于华南与印支块体的碰撞拼合作用。这也暗示华南与印支的碰撞拼合可能始于263～269 Ma。Better understanding on the formation and evolution of the convergence of the South China with Indochina Blocks had been restricted by the lack of precise geochronological data. Syntectonic granitic gneisses with NW-trending gneissic foliations are widely distributed in Wuzhishan area, Hainan Island. LA-ICP-MS zircon U-Pb dating of four samples yielded crystallization ages of 263–269 Ma, representing a key thermal-tectonic event in the Middle Permian. Combined with previous work, our dating results for the Wuzhishan orthogneiss suggest the Wuzihshan syntectonic granitic gneisses were derived from the convergence of the South China with Indochina Blocks. This age （263–269 Ma） might represent the initial time of the collision between the South China and Indochina Blocks.

关 键 词：花岗片麻岩 锆石 LA—ICP—MS U—Pb年代学 五指山地区 海南岛 

分 类 号：P597[天文地球—地球化学]