The study area is located in a Cu-Au metallization belt in Bainaimiao-Gunawusu, Inner Mongolia. A set of quartz-vein group is found in the Xuniwusu Formation by recent geological mapping, distributing in the Shiertai area, west of Bainaimiao Cu-Au deposit, but exhibiting a large similarity with the gold metallization veins of Bainaimiao Cu-Au deposit. The mineral assemblage of the quartz-vein group can be divided into two stages: the early pyrite-quartz stage ( M1 ) and the late quartz-calcite stage (M2). In M1 stage, homogenization temperature of the three phase inclusion bearing daughter crystal is of 256 - 320 ℃, and salinity of 31.4％-39.8％ NaCl eqv. Homogenization temperature of the two-phase aqueous inclusion is of 210 - 260 ℃, and sa-linity of 17.1％ -22.8％ NaCl eqv, and CH4enriched, less CO2, H2O , and small amount of H2S, C6H6, N2at gas phase composition; whereas by temperature of 170-210 ℃, CO2 or H2O enriched, less CH4, and minor N2, the salinity is as much as that of the former, but with participation of low salinity end-member. The CH4 and CO2 or only CH4 is shown by the pure gas inclusion. In M2 stage, homogenization temperature of two-phase aqueous inclusions is of 90 - 160 ℃, salinity of 15.82％ -21.1％ NaCl eqv, and the two-phase aqueous inclusion has a mixture with low salinity fluid. It is proposed that fluids of quartz-vein group should be regarded as a CH4 - CO2- H2O - NaCl system in the low salinity and low temperature with a small amount of H2S and N2, C6H6. In comparison with gold ore-forming fluid, fluid inclusion of Bainaimiao Cu-Au deposit, and data of chemical analysis of quartz-vein group, we suggest that the quartz-vein group would be a potential exploration target of gold metallization.%研究区位于内蒙古白乃庙-谷那乌素铜金成矿带,地质填图发现:白乃庙铜金矿床西侧徐尼乌苏组中发育一套石英脉群,产状与白乃庙矿区金矿化石英脉相似.其矿物组合可分为黄铁矿-石英早阶段(M1)和石英-方解石晚阶段(M2).M1阶段捕获的流体包裹体中,含子晶三相包裹体均一温度为256～320℃,盐度为31.4%～39.8%NaCl eqv;两相水溶液包裹体的均一温度为210～260℃时,盐度为17.1%～22.8%NaCleqv,气相富集CH4,CO2次之,含H2S、H2O及少量C6H6、N2,温度为170～210℃时,气相富集H2O或CO2,CH4次之,含N2,盐度与前者相似,但存在低盐度流体端员;纯气体包裹体成分为纯CH4或者CO2和CH4.M2阶段捕获两相水溶液包裹体,均一温度为90～160℃,盐度为15.82%～21.1%NaCl eqv,并与低盐度流体混合.石英脉群的流体可以看作中低温中低盐度含H2S、N2、C6H6的CH4-CO2-H2O-NaCl体系.对比金矿床成矿流体、白乃庙铜金矿床流体特征并结合化学分析,表明石英脉群具有金矿化的潜力.
展开▼
