冀西北水泉沟杂岩体及与其有关金矿床的^(40)Ar-^(39)Ar同位素年代学研究  

^(40)Ar-^(39)Ar Geochronology of the Shuiquangou Alkaline Complex and Related Gold Deposits, Northwestern 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》2000年第6期621-627,共7页Geological Review

基　　金：原地质矿产部"九五"重点科技找矿项目"冀北与碱性-偏碱性杂岩体有关的大型-超大壁金矿床成矿作用的定位预测"课题的资助

摘　　要：冀西北金矿集中区是我国华北地台北缘金矿成矿带的重要组成部分,区内金矿主要产于水泉沟碱性杂岩体及邻近的太古宙变质岩内。Ar-Ar同位素年龄测定结果显示,金矿床成矿年龄(172～188 Ma)与水泉沟碱性杂岩体的形成年龄(304～306 Ma)相差达120 Ma。综合研究推断金矿床不是碱性岩浆直接演化产物,而是在燕山期构造—岩浆活动影响下,地下循环热流体对矿源岩——碱性杂岩体淋滤、萃取,形成富含金的成矿热液,最终在有利的成矿构造部位沉淀富集的结果。因此本区的金矿床均属于与碱性杂岩体有关的改造型热液金矿。The northwestern Hebei gold concentration area is an important component part of the gold metallogenic belt along the northern margin of the North China craton. Most gold deposits in this area occur within the Shuiquangou alkaline intrusive complex or near metamorphic rocks of the Archean Sanggan Group. Based on 40Ar-39Ar isotopic analyses, there is a 120 Ma gap between the ore-forming age (172-188 Ma) of the deposits and the rock-forming age (304-306 Ma) of the Shuiquangou alkaline intrusive complex. Therefore, it may be concluded that the gold deposits are not the product of magmatic hydrothermal fluid. The ore-forming fluid may be composed of the circulating subsurface heated meteoric water and/or metamorphic fluid, and the ore-forming materials were mainly leached and extracted from the alkaline intrusive complex. The Mesozoic Yanshanian tectono-magmatic activities may have provided heat and dynamic energy for the ore-forming processes. So the gold deposits occurring in northwestern Hebei are considered as belonging to reworked hydrothermal gold deposits related to the alkaline intrusive complex.

关 键 词：氩同位素 碱性杂岩体 金矿床 矿床成因 年代学 

分 类 号：P618.51[天文地球—矿床学]