西藏冈底斯中段雄村铜金矿床流体包裹体研究  

Fluid inclusion studies of the Xiongcun copper-gold deposit in central Gangdese, Tibet

作　　者：徐文艺[1] 曲晓明[1] 侯增谦[1] 陈伟十[1] 杨竹森[1] 崔艳合[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《岩石矿物学杂志》2005年第4期301-310,共10页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目(40303008);科技部"973"计划资助项目(2002CB412605)

摘　　要：对西藏雄村铜金矿开展了系统的流体包裹体岩相学研究、显微测温和单个包裹体拉曼光谱分析。研究揭示雄村铜金矿床流体包裹体均一温度范围为121～382℃,成矿主体温度范围为150～250℃,均一压力范围为1.94×105～45.92×105Pa;铜矿化阶段盐度范围为1.23%～36.61%,总体盐度分布表现为3个不连续区间;铜矿化阶段存在高盐度流体,金矿化阶段为低温低盐度流体。雄村矿床温度、压力特征与浅成热液矿床基本一致,但盐度偏高,成矿流体组成以高Ca2+和富含CO2、N2、CH4为特征,主要离子组成为Na+_Ca2+_K+_Cl-_SO2-4。雄村铜金矿床成矿流体为一复杂的不混溶体系,至少存在3种流体端员,即富CO2_N2_CH4气体端员、低盐度水溶液端员和高盐度水溶液端员,流体不混溶是雄村矿床金属沉淀的一个重要机制。雄村矿床兼具高硫化和低硫化浅成热液矿床某些典型特征,但与典型的高硫化和低硫化浅成热液矿床又存在差异,为一“较为特殊的浅成热液矿床”。Based on such means as systematic petrographical study, microthermometry, and Raman probe analysis, the authors revealed that homogenization temperatures of fluid inclusions in vein quartz from the Xiongcun copper_gold deposit vary from 121℃ to 382℃, mainly in the range of 150℃～250℃. Homogenization pressures of fluid inclusions vary from 1.94×10~5 Pa to 45.92×10~5 Pa. Fluid inclusion salinities at the stage of copper mineralization vary in a wide range from 1.23 wt%NaCl_(eq). to 36.61wt%NaCl_(eq)., and are distributed in three discontinuous domains. High_salininity fluids existed at the stage of copper mineralization, but gold mineralization was related to low temperature and low salinity fluids. Fluid temperature and pressure characteristics of the Xiongcun deposit coincide with those of epithermal type deposits, but the salinity of the former deposit is higher than that of typical epithermal deposits. Ore_forming fluids of the Xiongcun deposit are rich in Ca^(2+), CO_2, N_2 and CH_4,thus belonging to the Na^+_Ca^(2+)_K^+_Cl^-_SO^(2-)_4 system. During the ore_forming process, there existed at least three fluid end_members in the Xiongcun deposit, namely the CO_2_N_2_CH_4_rich member, the low_salinity aqueous member, and the high_salinity aqueous member. Ore_forming fluids of the Xiongcun deposit formed a complex immiscible system, and fluid immiscibility seems to have been one of the important mechanisms for metallic deposition in the Xiongcun deposit. The Xiongcun copper_gold deposit is a peculiar epithermal deposit, which show some typical characteristics of both high_sulfidation epithermal deposits and low_ sulfidation epither_mal deposits.

关 键 词：流体包裹体 拉曼光谱 流体不混溶 浅成热液 雄村 铜金矿床 

分 类 号：P618.41[天文地球—矿床学] P618.51[天文地球—地质学]