冀西北水泉沟杂岩体成因的Nd同位素证据  

Nd-isotope Constrants on Origin of the Shuiquangou Intrusive Complex, North-Western Hebei, China

作　　者：江思宏[1] 聂凤军[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质论评》2003年第4期355-360,共6页Geological Review

基　　金：国家自然科学基金(编号40073015)和国土资源大调查项目(编号K1.3.32)联合资助成果

摘　　要：水泉沟碱性杂岩体是冀西北金矿集中区最重要的赋矿岩体。长期以来,关于水泉沟杂岩体的成因一直争议很大,严重制约了本区金矿床理论研究水平的提高。本文对水泉沟杂岩体及其围岩太古宙变质岩进行了系统的Nd同位素研究。研究结果表明,水泉沟杂岩体不可能是太古宙变质岩混合岩化或重熔的产物,而是由来自地幔的岩浆与下地壳局部熔融的物质不均匀混合形成的。Shuiquangou alkaline intrusive complex, which intruded into the Archean metamorphic rocks during Her-cynian orogeny, is the most important ore-bearing intrusive body in northwestern Hebei Province. The debate has been existed about the origin of the Shuiquangou complex for two decades. Based on the detailed Nd-iso-topic features study on the Shuiquangou complex and Archean metamorphic rocks. it shows that Shuiquangou complex is not the migmatization product of Archean metamorphic rocks. It is supposed that Shuiquangou alkaline intrusive complex was derived from inhomogeneous mixture of two kinds of magma, which were formed in under-melting from the mantle and in partly melting from the lower crust, respectively. Because of high speed of upward movement, these two kinds of magma have not enough time to mix and evolve sufficiently. Therefore , it causes that the isotope system of the magma evolved insufficiently and the intrusive complex lacks distinct petrographical facies. Moreover, the rock type, chemical composition and isotopic composition became more complicated when the intruding magma assimilated many wall rocks.

关 键 词：成因 水泉沟 碱性杂岩体 河北 ND同位素 钻同位素 太古宙变质岩 地球化学牲 金矿床 

分 类 号：P597[天文地球—地球化学]