西藏达若洛陇矽卡岩铜矿流体包裹体研究

Characteristics of Fluid Inclusions in the Daruoluolong Sharn Copper Deposit,Tibet

为揭示西藏双湖县达若洛陇矽卡岩型铜矿的成因,对该矿床石英-硫化物阶段和石英-碳酸盐阶段的石英和方解石中的流体包裹体进行了岩相学、显微测温学和激光拉曼光谱分析研究。结果表明,该矿床发育富液相气液两相(LV)、含子矿物三相(LVH,子矿物为石盐)、富气相气液两相(VL)和纯气相(V) 4类流体包裹体。石英-硫化物阶段脉体的石英(Q1)中以LV和LVH型包裹体为主,其均一温度集中于150~350℃,盐度分别为5%~25%Na Cleqv和30%~40%Na Cleqv。石英-碳酸盐阶段脉体的石英(Q2)和方解石中以LV型包裹体为主,均一温度集中于150~200℃,盐度集中于5%~10%NaCleqv。根据经验公式计算得到主成矿的深度为0. 8~1. 9 km。Q1中见有不同类型(LV、LVH、V)包裹体在同一视域下共存,且具有相似的均一温度但盐度变化较大,这是流体沸腾的明显标志。温度降低和沸腾作用是导致达若洛陇矿床Cu元素沉淀的主要因素。

In order to discuss characteristics of the ore-forming fluids and metallogenesis of the Daruoluolong sharn copper deposit,petrography,micro-thermometry,and Laser Raman Spectrum studies of fluid inclusions in the quartz-sulfide stage and quartz-carbonate stage have been carried out in this paper. There are four types of fluid inclusions,including liquidrich(LV),daughter mineral-bearing(LVH),vapor-rich(VL) and pure vapor(V). The quartz(Q1) of quartz-sulfide stage mainly contains LV and LVH fluid inclusions,which have same homogenization temperatures of 150 to 350 ℃ but different salinities ranging from 5% to 25% Na Cleqvand 30% to 40% Na Cleqv,respectively. In comparison,quartz(Q2) of quartz-carbonate stage mainly contains LV fluid inclusions with homogenization temperatures of 150 to 200 ℃ and salinities from 5% to 10%NaCleqv. On the basis of empirical equation,the depth of mineralization is estimated to be 0. 8-1. 9 km. In addition,different types of fluid inclusions,including LV,LVH and V fluid inclusions,could be observed in one quartz grain,showing similar temperature but different salinity. Therefore,fluid boiling and the decrease of temperature are the dominant controlling factor for Cu mineralization in the Daruoluolong sharn deposit.