山西省繁峙县义兴寨金矿为一大型石英脉型矿床。对义兴寨矿区金矿石中的流体包裹体进行了岩相学和显微测温研究,结果表明:义兴寨金矿各成矿阶段金矿石中的流体包裹体主要为气液两相的H2O包裹体,其次为纯气相H2O包裹体和含CO2包裹体。激光拉曼探针分析表明,第Ⅰ阶段流体包裹体除SO2特征峰外,还出现了CO2特征峰和C6H6特征峰,第Ⅱ阶段石英中流体包裹体的气相成分伴有一定量的SO2。第Ⅰ阶段包裹体的完全均一温度(均一至液相)为149~384℃,第Ⅱ阶段包裹体的完全均一温度(均一至液相或气相)为151~373℃,富气相包裹体多数在达到均一前发生爆裂,第Ⅲ阶段包裹体的完全均一温度(均一至液相)为246~325℃,第Ⅳ阶段包裹体的完全均一温度(均一至液相)为223~269℃。成矿流体为中温、低盐度的浆控热液,主成矿期发生流体沸腾并在第Ⅱ阶段有不同来源流体混入,后期有大气降水的加入。早期成矿阶段的流体具有深部地壳甚至地幔的特征。
The Yixingzhai gold deposit is a large-size quartz-vein type ore deposit.The ore microscopy and measured temperature data of fluid inclusions reveal that inclusions at various ore-forming stages of the Yixingzhai gold deposits are mainly gas-liquid two-phase(H2O or H2O-CO2) inclusions and subordinately pure volatile inclusions.Raman analysis of the fluid inclusions indicates that,in the gaseous phase,SO2,CO2 and C6H6 are existent at ore-forming stage Ⅰ,and SO2 is existent at stageⅡ in addition to water vapor.The homogenization temperatures of ore-forming stage Ⅰare 149~384℃(homogenization to liquid),and those of stage Ⅱare 151~373℃(homogenization to liquid or gas).Volatile-rich fluid inclusions are mostly decrepitated before homogenization.The homogenization temperatures of stage Ⅲ are 246~325℃(homogenization to liquid),and those of stage Ⅳare 223~269℃(homogenization to liquid).The ore-forming fluids are of the epithermal-mesothermal and low salinity hypothermal system.The ore-forming fluids boiled very impetuously at the main stage,the meteoric water participated the activity during the late stage,and the ore-forming fluids were mixed with other fluids from different sources at stage Ⅱ.The reducibility of the early ore-forming stage fluid came from continental deep crust or the mantle.