胶东三甲金矿床流体包裹体特征  

Fluid inclusions in the Sanjia lode gold deposit,Jiaodong Peninsula of eastern China.

作　　者：胡芳芳[1] 范宏瑞[1] 于虎 刘振豪 宋林夫 金成伟[1] 

机构地区：[1]中国科学院地质与地球物理研究所矿产资源研究重点实验室,北京100029 [2]山东金洲矿业集团有限公司,乳山264501

出　　处：《岩石学报》2008年第9期2037-2044,共8页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(40625010;40721062);中国科学院知识创新工程青年人才领域前沿项目资助

摘　　要：三甲金矿是胶东牟平—乳山金成矿带内重要的石英脉型金矿,金主要产于黄铁矿和多金属硫化物石英脉中。流体包裹体研究表明,三甲金矿蚀变岩石和各成矿阶段金矿石中的流体包裹体主要有三种类型:H_2O-CO_2包裹体、富 CO_2包裹体和 H_2O 溶液包裹体。早期乳白色石英中主要赋存原生的 H_2O-CO_2包裹体;成矿期黄铁矿石英脉和多金属硫化物石英脉中的富CO_2包裹体主要为原生,随机分布,气液比变化较大,常与早期 H_2O 溶液包裹体共生且均一温度接近,显示不混溶流体包裹体组合特征;在成矿晚期的石英和方解石中主要发育原生 H_2O 溶液包裹体。显微测温结果显示,成矿前(第Ⅰ阶段)H_2O-CO_2包裹体的完全均一温度(T_(h,TOT),至液相)为280℃至416℃,成矿期(第Ⅱ和Ⅲ阶段)富 CO_2包裹体的完全均一温度为210～330℃,同期的 H_2O 溶液包裹体均一温度为253～377℃,成矿后(第Ⅳ阶段)H_2O溶液包裹体的均一温度为176～207℃。成矿流体为低盐度的 CO_2-H_2O-NaCl 型热液,成矿应力场转变导致的流体减压沸腾作用可能是三甲金矿金沉淀成矿的主要原因。Sanjia gold deposit is a typical lode gold deposit in the Muping-Rushan gold belt of Jiaodong Peninsula, eastern China. Gold occurs mainly in pyrite- and polymetallic sulfide-quartz vein/veinlet stockworks. Fluid inclusions in the altered wallrocks and gold ores show CO2-H2O-NaCl fluids of three main types, namely H2O-CO2, CO2-rich and aqueous inclusion. Early milk white quartz contains original H2O-CO2 inclusions. In the pyrite quartz vein and polymetallic-sulphide quartz vein, CO2-rich inclusions occur in isolation or cluster with large range of H2O/CO2, whereas the aqueous inclusions occur as secondary trails in microfractures cutting earlier quartz grains. On occasion CO2-rich inclusions with variable aqueous phase were co-occurrence within the same clusters, and mostly homogenize to liquid or vapor at the same temperatures, indicating immiscibility did occur at the deposit. Quartz and calcite in the late ore-forming stage developed original aqueous inclusion. Microthermometric data show the homogenization temperatures of the CO2-H2O inclusions in the early ore-stage fall in the range between 280 and 416℃. Homogenization temperatures, obtained mainly from CO2-rich inclusions with relatively small CO2 bubbles in the main ore-stages, range from 210 to 330℃, Homogenization temperatures of H2O aqueous inclusions at same stage with CO2-rich inclusions are between 253 and 377℃, Homogenization temperatures （ to liquid） of the aqueous inclusions in the late stage range from 176 to 207℃. Fluid immiscibility caused by change of mineralizing stress possibly led to the gold precipitation at Sanjia.

关 键 词：流体包裹体 成矿流体 脉状金矿床 三甲 胶东 

分 类 号：P618.51[天文地球—矿床学]