延边地区石井金银矿床成矿流体特征及矿床成因  

Ore-forming fluid characteristics and genesis of Shijing gold-silver deposit in Yanbian area

作　　者：赵璇 任云生[1] 郝宇杰[1] 陈聪[1] 商青青 李晨辉[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]吉林省有色金属地质勘查局603队,吉林珲春133300

出　　处：《世界地质》2017年第4期1133-1143,共11页World Geology

基　　金：国家重点研发计划项目(2017YFC 0601304)资助

摘　　要：为确定石井金银矿床的成矿物理化学条件和矿床成因,取主成矿阶段的石英—方解石脉,进行流体包裹体显微测温、激光拉曼光谱分析和H、O同位素测试。研究表明,石英和方解石中主要发育气液两相包裹体,少量为纯液相包裹体;所测包裹体的均一温度、盐度和密度的变化范围均较大,均一温度集中于240℃~280℃,盐度范围在0.18~18.10 wt%Na Cl,流体密度为0.57~0.97 g/cm^3,流体压力为9.24~48.19 MPa,估算的成矿深度介于0.31~1.61 km之间;流体包裹体气相成分主要为水,成矿流体属于中低温、低盐度、低密度的H_2O-NaCl体系。包裹体中δD变化范围为(-114.8^-106.1)×10^(-3),δ^(18)O_(H_2O)范围为(-3.03^-1.43)×10^(-3),成矿流体主要来自大气降水。根据成矿地质条件、蚀变矿化特征、成矿流体特征以及与国内外典型矿床对比研究认为,石井矿床的成因类型为低硫化型浅成低温热液型金银矿床。In order to determine the physical and chemical conditions and genesis of Shijing gold-silver deposit,microthermometric,laser raman spectrum and H-O isotopes analysis of fluid inclusions within the quartz-calcite vein formed in the major mineralization stage have been carried out. The results show that the majority of fluid inclusions in the samples are gas-liquid two-phase inclusions,occasionally pure liquid inclusions. The homogenization temperature,salinity and density of these fluid inclusions vary in wide ranges,which are from 240℃ to 280℃,0. 18 to 18. 10 wt% NaCl,0. 57 to 0. 97 g/cm^3,respectively,and the pressure of the two-phase inclusions ranges from 9. 24 to 48. 19 MPa. The estimated mineralization depth of Shijing deposit is 0. 31 to 1. 61 km. The gas phase in the fluid inclusion is mainly composed of H_2O. Fluid inclusion analyses indicate that the ore-forming fluid during the major mineralization stage is an H_2O-NaCl system,with medium-low temperature,low salinity and low density. The δD and δ^(18)OH_2O values of fluid inclusions in quartz samples from the Shijing deposit are from-114. 8 ×10^(-3) to-106. 1 × 10^(-3) and -3. 03 × 10^(-3) to-1. 43 × 10^(-3)respectively,indicating that the ore-forming fluidwas mainly sourced from meteoric water. According to the geological condition of mineralization,alteration,and ore-forming fluid,and the comparison with the typical deposits both in China and abroad,it can be concluded that the Shijing deposit is a low-sulfidation epithermal gold-silver deposit.

关 键 词：流体包裹体 低硫化型浅成低温热液型矿床 石井金银矿床 矿床成因 延边地区 

分 类 号：P618.5[天文地球—矿床学] P617.9[天文地球—地质学]