内蒙古火成岩Sr-Nd同位素特征及成因  

Genesis of Sr-Nd isotopic characteristics of igneous rocks in Inner Mongolia

作　　者：邵济安[1] 洪大卫[2] 张履桥 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国地质科学院地质研究所,北京100037 [3]内蒙古地质研究所,内蒙古呼和浩特010020

出　　处：《地质通报》2002年第12期817-822,共6页Geological Bulletin of China

基　　金：国家自然科学基金项目(40072073)资助。

摘　　要：收集了本区不同时期形成的各类火成岩,包括花岗岩、火山岩、岩墙群、堆晶岩、蛇绿岩的Sr-Nd等30组同位素数据,从中可以看到以下两个特征:①研究区从800Ma以来形成的包括蛇绿岩在内的火成岩都有高εNd低Sri的同位素特征,绝大多数Sri集中在0.7045～0.7060之间,εNd(t)集中在1～5之间。②TDM年龄较多集中在800～600Ma,个别为1000Ma。结合该区的地质-地球物理研究成果探讨了这些同位素特征值形成的构造背景。A total of 30groups of isotope age data such as Sr-Nd isotope age data and Nd model age data of igneous rocks,including granites,volcanic rocks,dyke swarms ,cumulates,and ophiolites,formed in different periods of time are reported in this paper,which show the following two features:(1)igneous rocks including ophiolites formed in this area since800Ma BP all have highε Nd and low Sr i ,with most Sr i values centered in the range of 0.7045to0.7060andε Nd (t)values in the range of 1to5,and(2)most of the TDM ages are in the range of 800to600Ma ,with only a few at1000Ma.The tectonic setting for forming these isotope characteristic values is discussed in combination with the geological-geo-physical data of this area.

关 键 词：内蒙古 火成岩 高εNd(t)低Sri TDM值 构造背景 

分 类 号：P588.1[天文地球—岩石学]