山西辛庄金矿床成矿流体特征及矿床成因  

Ore-forming fluid characteristics and ore genesis of Xinzhuang gold deposit, Shanxi province

作　　者：郑明泓[1,2] 邵拥军[1,2] 赵晓霞[1,2] 刘忠法[1,2] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083

出　　处：《中国有色金属学报》2014年第10期2609-2620,共12页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划资助项目(2007CB411405);国家"十一五"科技支撑计划资助项目(2006BA01B07);国土资源部公益性行业科研专项经费资助项目(200911007-04);国家危机办项目(20109901);中南大学有色金属成矿预测教育部重点实验室发展基金资助项目

摘　　要：辛庄金矿位于山西陆台五台隆起西北侧与燕山沉降带西南缘两大构造单元相互嵌接的中生代构造岩浆活动带上，矿体产状受NNW和NW向断裂控制。根据脉体穿切关系和矿物交代关系，可以将辛庄金矿分为早、中、晚3个成矿阶段。本区流体包裹体主要以气液两相包裹体为主，成矿温度有两个峰值：320∽340℃和220∽260℃，分别对应石英-黄铁矿阶段和石英-多金属硫化物阶段，属于中高温的范围。包裹体气相成分以H2O和CO2为主，并含有一定量的CH4以及极少量的H2、C2H2和C2H6；液相成分主要有Ca2＋、Mg2＋、Na＋、K＋、SO42-、Cl-和F-。本区氢氧同位素组成表明成矿流体具有大气降水与深部岩浆流体混合特点。总体而言，辛庄金矿的初始流体具有中高温、富CO 2、低盐度的流体特征，晚成矿阶段流体演化为低温、低盐度水溶液流体，流体的不混溶导致了主成矿期矿质的大量沉淀。辛庄金矿为与燕山期岩浆活动有关的热液型金矿床。Xinzhuang gold deposit is located in the Mesozoic tectonic-magma activation area which is embedded by the two tectonic units-the northwestern Wutai uplifts of Shanxi platform and the southwestern Yanshanian subsidence belt. The occurrence of the ore body is controlled by NNW and NW faults. The crosscutting relationships and mineral replacement suggest that the ore forming process includes the earlier, middle and later stages. The fluid inclusions of the ore in this deposit are mainly the gas-liquid inclusions. The ore-forming temperatures have two peak values： 320-340℃ and 220-260℃, corresponding to the quartz-pyrite-chalcopyrite stage and the quartz-polymetallic sulfide stage, respectively, which indicates that the deposit belongs to the hypo-mesothermal gold deposit. The gas compositions in the fluid inclusions mainly include H2O and CO2, with trace CH4 and H2, C2H2 and C2H6. The liquid phase mainly contain Ca2＋, Mg2＋, Na＋, K＋, Cl-, SO42-, Cl- and F-. The composition of hydrogen and oxygen means the mixing of meteoric water and deep magmatic fluid. In general, the ore fluids in the early and middle stages are characterized by meso-to hypothermal CO2-rich and low salinity, which are considered as the nature of metamorphic fluids, whereas the late-stage fluids are low temperature, low salinity and CO2-poor. The fluid immiscibility causes gold precipitation in the middle-stage. The Xinzhuang gold deposit belongs to the quartz vein type related to the Yanshanian mediosilicic-acid magma activities.

关 键 词：流体包裹体 成矿流体 矿床成因 辛庄金矿床 

分 类 号：P611.1[天文地球—矿床学]