摘要
湘西南-桂北交界地区属于江南造山带(或称之为钦杭结合带)西南段的重要组成部分,该区与Rodinia超大陆聚合与裂解有关的岩浆活动十分强烈,但至今还没有加里东期基性岩存在的报道。采用LA-ICP-MS锆石U-Pb法对湘西南—桂北交界地区首次发现的加里东期变辉长辉绿岩进行了年代学研究。结果表明,变辉长辉绿岩形成于(421.9±7.8)Ma,为加里东期岩浆活动的产物。该基性岩的发现及其年龄的确定;并结合区域上的研究结果表明,扬子板块和华夏板块结合带(钦杭结合带)西南段可能存在有从新元古代至早古生代的双向洋陆俯冲-碰撞过程。
The southwestern Hunan-northern Guangxi border area is an important ment of Jiangnan orogenic belt (so-called Qinzhou-Hangzhou joint belt). There is a related to the assembly and break-up of Rodinia supercontinent, but Caledonian mafic part of the southwestern seg- very strong magmatic activity rocks have not been found in this area. Geochronology of Caledonian metamorphic gabbro-diabase discovered firstly in southwestern Hunan-north- ern Guangxi border area was studied by using LA-ICP-MS zircon U-Pb method. The research results showed that the metamorphic gabbro-diabase is developed during (421.9 + 7.8 ) Ma, and it is the product of Caledonian mag- matism activity. The discovery of Caledonian mafic rock and the determination of its era, and in combination with the regional research results, we consider that there was likely a double ocean-continent subduction-collision event occurred during Neoproterozoic to early Paleozoic time.
出处
《科学技术与工程》
北大核心
2016年第5期19-25,共7页
Science Technology and Engineering
基金
广西自然科学基金项目(2013GXNSFAA019272)
桂林理工大学人才引进科研启动基金项目(002401003364)
中国地质调查局地质矿产调查评价项目(12120114039501、12120113095600)联合资助
关键词
江南造山带
加里东期
基性岩
锆石U-PB年代学
湘西南—桂北交界地区
Jiangnan orogenic belt Caledonian mafic rock zircon LA-ICP-MS U-Pb dating southwestern Hunan-northern Guangxi border area