金沙江中段共波加里东期辉长岩锆石U-Pb年龄测定  

U-Pb Zircon Dating of the Caledonian Gongbo Gabbro from the Mid-Jinshajiang Area,Sichuan Province

作　　者：简平[1] 刘敦一[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《地质论评》2002年第S1期17-21,共5页Geological Review

基　　金：国家自然科学基金资助项目(编号49902005)的成果

摘　　要：川西得荣县共波、中木至中心绒南的沿金沙江一线出露辉长辉绿岩。共波辉长岩的锆石U-Pb年龄测定给出下交点年龄448±7 Ma,上交点年龄1821±81 Ma。在一致曲线图中,数据点均靠近下交点,且在7个分析中,有一个分析给出了约477±7 Ma的一致年龄,这表明共波辉长岩的侵位年龄可能为448±7 Ma至478±7 Ma。本文提出了金沙江地区加里东期辉长岩侵位与古特提斯洋盆的早期演化,即与大陆裂开有关的观点。Gabbro-diabases are exposed along the Jinsha River in areas from Gongbo, Zhongmo to Zhongxinrong, Derong County, Western Sichuan Province. U-Pb dating of zircons from the Gongbo gabbro has yielded a relatively low intercept age of 448 ± 7 Ma, and an upper intercept age of 1821 ± 81 Ma. On the concordia diagram, all data points are close to the lower intercept, and among 7 analyses, one zircon gives a concordant age of 478 ±7 Ma. The paper points out that the Caledonian gabrro emplacement is in relation to the early evolution of the Paleo-Tethyan oceanic basin or continental rifting in the Jinshajiang region.

关 键 词：金沙江 辉长岩 U-PB年龄 加里东期 大陆裂开 

分 类 号：P597.3[天文地球—地球化学]