摘要
Ｓｍ－Ｎｄ同位素测龄研究表明，赣东北广丰地区桃源组火山岩的Ｓｍ－Ｎｄ等时线年龄为（１１００±１６８）Ｍａ，形成时代应归属晚元古代，与扬子、华夏两板块在晋宁期对接造山作用的时间一致。岩石学、岩石地球化学的系统研究表明，该组火山岩富碱、Ｋ２Ｏ，Ａｌ２Ｏ３，ＬＲＥＥ及地幔不相容元素，属碱性系列中的钾玄岩系列；低εｔ（Ｎｄ）（－４．５±１．９），Ｉｔ（Ｓｒ）为０．７０４８～０．７１３１，变化范围很大，具壳幔混合成因的Ｓｍ－Ｎｄ、Ｒｂ－Ｓｒ同位素组成。笔者研究认为，桃源组钾玄岩系列火山岩是晋宁期岛弧火山岩的重要组成部分。
It has been showed by the study of Sm Nd isotopic age that the Taoyuan volcanic rocks from Guangfong County of north eastern Jiangxi Province were formed at (1100±168)Ma during Upper Proterozoic Subera.This age is same with the age when collision orogen happened between Yangzi and Huaxia plates.The studies of petrology,petrochemistry also showed that the volcanic rocks are rich in Alk,K 2O,Al 2O 3,LREE and incompatible elements,and are of shoshonite series,and have a mantle crust mixed Sm Nd ε(Nd) is -4.5±1.9 and Rb Sr ( I t (Sr) is 0.704 8～0.713 1) isotopic composition.It is suggested that the Taoyuan shoshonite is an important part of the arc volcanic rocks formed by subduction between Yangzi and Huaxia plates during Upper Proterozoic Subera.
出处
《地质科技情报》
CAS
CSCD
北大核心
1999年第2期5-9,共5页
Geological Science and Technology Information
基金
国家计委和原地矿部"八五"地勘专项
关键词
晚元古代
钾玄岩系列
岛孤火山岩
岩石学
North eastern Jiangxi Province,Upper Proterzoic Subera,shoshonite series,arc volcanic rock
