滇西北兰坪盆地金满脉状铜矿床成矿流体特征及其成矿意义

发布时间：2018-03-25 18:27

  本文选题：成矿流体　切入点：沉积岩容矿脉状铜矿床　出处：《吉林大学学报(地球科学版)》2017年03期

【摘要】：滇西北兰坪盆地西缘发育大量沉积岩容矿脉状铜多金属矿床,矿体的分布受逆冲推覆系统控制,金满是其中储量最大、品位最高的铜矿床。成矿过程可分为3个阶段:成矿前(不含矿化石英-铁白云石脉)、主成矿阶段(含铜硫化物石英脉)、晚成矿阶段(少硫化物方解石+石英脉)。流体包裹体岩相学和显微测温结果表明:成矿前和主成矿期石英中流体包裹体特征变化不大,成矿前和主成矿期石英中均存在3种类型的包裹体,以水溶液包裹体为主,含CO_2水溶液包裹体次之,富CO_2包裹体较少出现。含CO_2水溶液包裹体测温结果也差别不大,均一温度都集中在240320℃,盐度(w(NaCl))集中在1%4%。水溶液包裹体均一温度变化也不大,集中在160 230℃,明显低于含CO_2水溶液包裹体;盐度却存在较大的变化,主成矿期盐度变化范围明显较大,且峰值高于成矿前。晚成矿阶段则仅出现水溶液包裹体,均一温度和盐度都明显降低,均一温度集中在120185℃,盐度集中在1.4%9.3%。结合其他证据,笔者认为金满铜矿床包含两种不同性质的流体:深源流体,以中高温、中低盐度、富含CO_2为特征;盆地卤水,以中低温、中高盐度、贫CO_2为特征。成矿过程中未发生明显的沸腾和相分离作用,深源流体和盆地卤水的混合可能是导致Cu等成矿元素沉淀的重要机制。
[Abstract]:In the western margin of Lanping basin in northwest Yunnan, a large number of sedimentary rock containing vein copper polymetallic deposits are developed. The distribution of orebodies is controlled by the thrusting and nappe system, in which the gold reserves are the largest. Copper deposit with the highest grade. The metallogenic process can be divided into three stages: before mineralization (no mineralized quartz-iron dolomite vein), main metallogenic stage (copper sulfide quartz vein), late metallogenic stage (oligosulphide calcite quartz vein). The petrographic and microthermometric results of fluid inclusions show that the characteristics of fluid inclusions in quartz before and during the main metallogenic period do not change much. There are three types of inclusions in quartz before and during the main metallogenic period. The main inclusions are aqueous inclusions, followed by aqueous inclusions containing CO_2, and the inclusions rich in CO_2 are rare. The results of temperature measurement of aqueous inclusions containing CO_2 are not different. The homogenization temperature is concentrated at 240320 鈩，

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