投稿时间：2011-08-28
修订日期：2012-03-01
中文摘要:哈播斑岩Cu-(Mo-Au)矿床产于哀牢山富碱斑岩带的南段,形成于青藏高原后碰撞阶段构造转换环境,属于陆-陆碰撞型斑岩矿床。根据脉体的交切关系,确定哈播矿床各种脉的演化序列为早期石英脉→石英-黄铜矿脉→石英-辉钼矿脉。脉中流体包裹体的岩相学、显微测温和激光拉曼光谱分析等研究结果显示,各期脉中均有富气相包裹体、富液相包裹体和含子矿物多相包裹体,各种包裹体的气相均含有CO2、SO2、H2O等气体。各期脉中多种包裹体并存并具有相似的均一温度范围,富液相包裹体均一温度149~427℃, 盐度ω(NaCleq) 6.0%~15.0%; 富气相包裹体均一温度205~405℃, 盐度ω(NaCleq) 3.4%~19.0%; 含子矿物多相包裹体均一温度305~516℃, 盐度ω(NaCleq) 33.5%~61.0%。 哈播矿床的初始成矿流体由稳定共存、不混溶的低盐度流体和高盐度流体组成, 高盐度流体是哈播矿床成矿元素迁移的主要载体。 成矿流体在400℃左右发生"二次沸腾"、 分相, 温度下降和挥发分持续逃逸可能是Cu-Au成矿的诱因。Mo元素在成矿流体多次沸腾、分相过程中,持续优先分配进入高盐度流体中而逐步富集;温度下降,使含钼硫化物在流体中溶解度降低、沉淀,形成石英-辉钼矿±黄铜矿脉。
Abstract:The Habo porphyry Cu-(Mo-Au) deposit is located in the south of Jinshajiang -Ailaoshan orogenic belt. It is a typical post-subduction porphyry deposit formed in a Tibetan post-collision transformation setting. Intense K-feldspar and biotite alteration associated with quartz stockwork occurs in the Habo deposit alteration center, which is surrounded and overprinted by later feldspar-destructive alteration. Several stages of veinlets can be observed, and the evolution sequence of vein types is magnetite-quartz veinlets→early quartz veinlets→quartz-chalcopyrite veinlets→quartz-molybdenite veinlets→quartz-sericite-pyrite veinlets →pyrite-chalcopyrite veinlets. Early quartz, quartz-chalcopyrite and quartz-molybdenite veinlets were selected to perform fluid inclusion study. The cathodoluminescence images of early quartz, quartz-chalcopyrite and quartz-molybdenite veinlets indicate that they all were overprinted by later hydrothermal fluids. Vapor-aqueous inclusions, aqueous inclusions, and high brine halite-bearing inclusions were found in all the three types of veinlets, and CO2-bearing inclusions were found locally. Using Laser Raman analysis, the authors found that CO2 and SO2 are very abundant in all these inclusions. In early quartz, quartz-chalcopyrite and quartz-molybdenite veinlets, vapor-aqueous inclusions were homogenized within 149~427℃ with salinity ω(NaCleq) of 6.0%~15.0%, aqueous inclusions were homogenized within 205~405℃ with salinity ω(NaCleq) of 3.4%~19.0%, and high brine halite-bearing inclusions gained homogenization within 305~516℃ with salinity ω(NaCleq) of 33.5%~60.8%. Vapor-aqueous and high brine halite-bearing inclusions are abundant in early quartz veins, and their homogenization temperatures are similar, which shows that in the Habo deposit the silicate melt directly exsolved two coexisting fluid phases, a vapor and a hypersaline liquid, and the hypersaline fluid is the main carrier of metals. When the fluids migrated upward, at the temperature of ~400℃, the hypersaline liquid entered the two-phase separation field, causing intense boiling and phase separation. With the vapor fluids escaping, the solubility of Cu-Au in the hypersaline fluid decreased, accompanied by intense Cu-Au mineralization. Mo was partitioned into hypersaline fluid during the whole fluid evolution and enriched gradually. On progressive cooling and boiling, the solubility of both Mo and silicates decreases, which accounts for Mo saturation and deposition.
文章编号：
中图分类号：P618.41;P618.65;P618.51
文献标志码：
基金项目:本文为国家重点基础研究发展计划(973计划)项目(编号:2009CB421002、2002CB412600);高等学校创新引智计划("111计划");"成矿动力学基地"(B07011)和国家基金项目(编号: 40873023、40830317);国家地调项目(1212010610104)资助成果
引用文本：
祝向平,莫宣学,NoelCWHITE,孙明祥,赵思礼.2012.云南哈播斑岩铜(-钼-金)矿床流体包裹体研究[J].矿床地质,31(4):839~849ZHU XiangPing,MO XuanXue,Noel C WHITE,SUN MingXiang,ZHAO SiLi.2012.Fluid inclusions of Habo porphyry Cu-(Mo-Au) deposit, Yunnan Province[J].Mineral Deposits31(4):839~849
图/表
