湘东锡田垄上锡多金属矿床流体包裹体研究  

Fluid inclusion studies of Longshang tin-polymetallic deposit in Xitian ore field,eastern Hunan Province

作　　者：杨晓君[1] 伍式崇 付建明[1] 黄惠兰[1] 常海亮[1] 刘云华[1] 魏君奇[1] 刘国庆[1] 马丽艳[1] 

机构地区：[1]宜昌地质矿产研究所,湖北宜昌443003 [2]湖南省地质调查院株洲矿产地质调查所,湖南株州412007

出　　处：《矿床地质》2007年第5期501-511,共11页Mineral Deposits

基　　金：中国地质调查局项目(1212010533307)的资助

摘　　要：锡田垄上锡多金属矿床是湘东锡田锡矿田中的一个大型矿床。通过对锡田垄上矽卡岩型和破碎带蚀变岩型锡多金属矿石中的萤石和石英流体包裹体的岩相学、显微测温分析、包裹体成分的激光拉曼探针分析,结果显示锡田垄上流体包裹体可分为3类5型。3类:盐水包裹体(A类)、富CO2两相包裹体(B类)和含CO2三相包裹体(C类);5型:单相盐水溶液包裹体(A1型)、气液两相盐水溶液包裹体(A2型)、富CO2两相包裹体(B型)、均一成LH2O的含CO2三相包裹体(C1型)和均一成VCO2的含CO2三相包裹体(C2型)。3个成矿阶段的均一温度分别为:Ⅰ成矿阶段为290～380℃;Ⅱ成矿阶段为210～240℃;Ⅲ成矿阶段为90～190℃。成矿早阶段(Ⅰ阶段),CO2、NaCl-H2O和NaCl-H2O-CaCl2各类型均一温度相近的包裹体共生,成矿流体成分主要为CO2和NaCl-H2O,含少量H2S和CH4;成矿晚阶段(Ⅱ、Ⅲ阶段),成矿流体成分主要为NaCl-H2O。根据流体包裹体特征,结合高3He/4He比值以及在锡田花岗岩中存在大量镁铁质微粒包体,笔者认为:锡田垄上锡多金属矿床成矿物质是多来源的,成矿流体为地幔、地壳和大气水的混合产物;锡多金属来源受岩浆和围岩控制,而在成矿作用过程中尤其是成矿早阶段,地幔成矿流体可能起到了积极的甚至关键的作用。The Longshang ore deposit is a large-size tin-polymetallic deposit in the Xitian ore field, eastern Hunan Province. Fluid inclusions in fluorite and quartz from the skarn and fracture zone altered rocks of the Longshang tin-polymetallic deposit were studied by such means as petrography, microthermometry and Laser Raman Spectrometer analysis. The results show that fluid inclusions are composed of NaCl-H2O type fluid inclusions （Type A）, CO2-rich two-phase inclusions （Type B）, and CO2-bearing three-phase inclusions （Type C）. Type A comprises single-phase liquid inclusions （A1） and two-phase liquid-vapor inclusions （A2）; Type B includes CO2-rich two-phase inclusions; and Type C consists of CO2-bearing three-phase inclusions which have been homogenizedinto LH2O（C1） and CO2-bearing three-phase inclusions which have been homogenized into VCO2 （C2）. The homogenization temperatures of the three ore-forming stages are 290-380℃ for Stage I, 210-240℃ for Stage II, and 90-190℃ for Stage III. At the early stage of the ore-forming process （Stage I）, fluid inclusions of CO2, NaCl-H2O and NaCl-H2O-CaCl2 types which had close homogenization temperatures were associated with each other, and the main ore-forming fluids were CO2 and NaCl-H2O with small amounts of H2S and CH4. At the late stages of the ore-forming process （Stage Ⅱ, Ⅲ）, the main ore-forming fluid was NaCl-H2O. According to characteristics of the fluid inclusions, high 3↑He/4↑He ratios and the existence of lots of mafic microgranular inclusions, the authors consider that the ore-forming materials of the Longshang tin-polymetallic deposit were derived from multiple sources. The ore-forming fluids were mixed with mantle, crust and atmospheric water. Under the control of igneous and surrounding rocks, the mantle ore-forming fluids played a key role in mineralization at the early stage of the ore-forming process.

关 键 词：地球化学 流体包裹体 地幔流体 成矿作用 锡多金属矿床 垄上 湘东 

分 类 号：P618.44[天文地球—矿床学]