滇西上地幔铅同位素演化模式及滇西富碱斑岩铅同位素组成的诠释  

The Pb Isotope Evolution Model of the Upper Mantle in Western Yunnan and Interpretation of Lead Isotopic Compositions of Regional Alkali-rich Porphyries

作　　者：吴开兴[1] 胡瑞忠[1] 毕献武[1] 张乾[1] 彭建堂[1] 

机构地区：[1]中国科学院地球化学研究所

出　　处：《地球学报》2004年第2期263-270,共8页Acta Geoscientica Sinica

基　　金：中国科学院知识创新工程重点项目"扬子地块西缘重大构造事件与高渗透构造域成矿物质迁移富集"(编号 :KZCX2 10 1) ;国家自然科学基金项目"富碱侵入岩成岩过程中流体聚集的地球化学研究"(编号 :40 0 0 3 0 0 7) ;国家重点基础研究发展规划项目"与不同源花岗质岩浆

摘　　要：大量的Pb同位素数据资料表明 ,滇西上地幔铅具两阶段演化历史 ,但又不是很好地吻合Stacey Kramers的两阶段模式。本文依据Stacey Kramers建造两阶段模式的基本原理 ,结合滇西地区上地幔铅同位素组成资料 ,拟合出了能更好地反映滇西上地幔铅同位素演化历史的二阶段模式并应用此模式对滇西富碱斑岩及其相关岩石的铅同位素组成做出诠释。Thirty Pb isotope data of the upper mantle in western Yunnan show trends similar to Stacey-Kramers′ two stage model growth curves but apparently deviate from the latter curves on the lead isotope composition programs. This may suggest that Pb isotope of the upper mantle in western Yunnan might have experienced two stages of evolution though it is not fit very well to Stacey-Kramers' two-stage model growth curves. In this paper,a two-stage growth curves model which can better fit the Pb isotope data was constructed on the basis of the lead isotope data of the upper mantle in western Yunnan. With this model,a reasonable interpretation is given to the lead isotopic compositions of the regional alkali-rich porphyries and their related rocks.

关 键 词：铅同位素 上地幔 二阶段模式 富碱斑岩 云南 侵人岩 

分 类 号：P588.12[天文地球—岩石学]