胶西北新城金矿成矿流体与矿床成因  

Ore-forming fluids and genesis of Xincheng altered rock gold deposit innorthwestern Jiaodong Peninsula

作　　者：陆丽娜[1] 范宏瑞[1] 胡芳芳[1] 杨奎锋[1] 郑小礼[2] 赵海[2] 

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]山东黄金集团有限公司,山东莱州264000

出　　处：《矿床地质》2011年第3期522-532,共11页Mineral Deposits

基　　金：国家自然科学基金项目(40625010);全国危机矿山接替资源找矿项目(20089930)资助

摘　　要：新城金矿是胶东招远-莱州成矿带内重要的蚀变岩型金矿。流体包裹体研究表明,新城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3种类型：H2O-CO2包裹体、富CO2包裹体和H2O溶液包裹体。早期乳白色石英中主要赋存原生的H2O-CO2包裹体;成矿期黄铁矿石英脉中的富CO2包裹体主要为原生,随机分布,常与同时期的H2O溶液包裹体共生且均一温度接近;在成矿晚期的石英和方解石中主要发育原生H2O溶液包裹体。显微测温结果显示,完全均一温度：成矿早期H2O-CO2包裹体为310~380℃,主成矿期富CO2包裹体为240~315℃,同期的H2O溶液包裹体为209~311℃,成矿晚期H2O溶液包裹体为147~170℃。氢、氧同位素表明新城金矿成矿流体为岩浆水与大气水形成的混合热液,硫同位素进一步揭示了金矿的物质来源为以围岩S或壳源S与幔源S相互作用的结果。区域应力场转变导致的流体减压沸腾作用可能是新城金矿金沉淀成矿的主要因素。The Xincheng gold deposit is a typical altered rock type gold deposit in the Zhaoyuan-Laizhou gold ore belt of Jiaodong Peninsula,eastern China.Fluid inclusions in altered wall rocks and gold ores show that CO2-H2O-NaCl fluids have three main types,namely H2O-CO2,CO2-rich and aqueous inclusions.Early milky white quartz contains original H2O-CO2 inclusions.In the pyrite quartz vein,CO2-rich inclusions occur in isolation or cluster,whereas the aqueous inclusions occur as secondary trails in microfractures cutting earlier quartz grains.Quartz and calcite of the late ore-forming stage developed original aqueous inclusions.Microthermometric data show that the homogenization temperatures of H2O-CO2 inclusions at the early stage fall in the range between 310℃ and 380℃,CO2-rich inclusions at the main stage range from 240℃ and 315℃,aqueous inclusions at the same stage are between 209℃ and 311℃.Aqueous inclusions at the late stage range from 147℃ to 170℃.D-O stable isotopes indicate that the main ore-forming fluid of the Xincheng gold deposit was the product of mixing between magmatic fluid and meteoric water,S stable isotopes further reveal that Au came from the source induced by the interaction between crustal/rock S and mantle S.Fluid immiscibility caused by change of mineralization stress possibly led to gold precipitation at Xincheng.

关 键 词：地球化学 流体包裹体 稳定同位素 蚀变岩型金矿床 新城 胶西北 

分 类 号：P618.51[天文地球—矿床学]