赣南—湘东湖南洞岩体的锆石U-Pb年代学研究及其对加里东构造背景的意义  

Zircon U-Pb Dating of the Hunandong-granite and Its Caledonian Tectonic Significance,South Jiangxi-East Hunan Province

作　　者：王永磊[1] 陈振宇[1] 陈郑辉[1] 侯可军[1] 赵正[1] 许建祥[2] 张家菁[2] 曾载淋[3] 

机构地区：[1]国土资源部成矿作用与资源评价重点实验室,中国地质科学院矿产资源研究所,北京100037 [2]江西省国土资源厅,江西南昌330000 [3]江西省地质矿产勘查开发局赣南地质调查大队,江西赣州341000

出　　处：《岩矿测试》2012年第3期525-529,共5页Rock and Mineral Analysis

基　　金：中国地质大调查项目"南岭地区岩浆岩成矿专属性研究"(1212011120989);"我国重要矿产和区域成矿规律研究"课题(1212010633903);国家深部探测技术与实验研究专项"南岭成矿带地壳岩浆系统结构探测实验"(SinoProbe 0301);"南岭于都-赣县矿集区立体探测技术与深部成矿预测示范"课题(201011048)

摘　　要：湖南洞岩体位于湘赣交界处,侵位于淋洋岩体中。在野外系统地质调查的基础上,对湖南洞岩体进行了详细的激光剥蚀-多接收器电感耦合等离子体质谱(LA-MC-ICPMS)锆石U-Pb同位素年龄测定。这些锆石的阴极发光图像发育环带结构,Th/U比值较高(大于0.1),具有岩浆成因锆石的特征。研究结果表明,湖南洞岩体锆石的206Pb/238U加权平均年龄为(447.2±1.8)Ma,为晚奥陶世,反映了华南加里东期岩浆活动的一个重要阶段。结合本次锆石U-Pb同位素定年结果及前人研究资料,认为湖南洞岩体的形成可能与扬子地块和华夏地块之间的碰撞拼贴作用有关,从而为进一步理解华南加里东期花岗质岩浆活动及其动力学背景等提供了有力的证据。Hunandong granite located on the border of Hunan and Jiangxi, intruded into the Linyang granite. Based on the investigation of field geology, detailed zircon U-Pb age measurements were done on the Hunandong granite. These zircons have high Th/U ratio with zonal structure, which indicate magmatie zircons. The zircon U-Pb age is （447.2± 1.8） Ma, which shows that the Hunandong granite was formed in the late Ordovician period, reflecting the important stage of Caledonian magmatism. According to the result together with other information published, the authors think that the formation of Hunandong granite may be related to the amalgamation and collision between Cathaysian block and Yantze block, providing strong evidence for further understanding the Caledonian magmatism and its geodynamic process in South China.

关 键 词：湖南洞岩体 LA-MC-ICPMS锆石U-Pb定年 加里东 

分 类 号：P59[天文地球—地球化学] O657.63[天文地球—地质学]