金川镍铜铂硫化物矿床矿石成因——来自铂族元素地球化学的证据

Ores genesis in Jinchuan Ni——Cu——(PGE) sulfide deposit: evidence from geochemistry of platinum group elements

对金川镍铜铂硫化物矿床Ⅰ、Ⅱ矿区主矿体典型钻孔中的不同类型矿石进行了系统观察和铂族元素分布特征研究。金川矿床中星点状矿石、网状矿石、块状矿石PGE总量依次降低,由西至东24号、1号、2号矿体的PGE总量亦具渐次降低趋势。形成块状矿石的硫化物熔体PGE分异作用较星点状和网状矿石更充分;块状矿石铂族元素分布特征显示其受晚期硫化物熔体分离结晶和单硫化物固溶体(MSS)分离作用控制。研究结果表明:星点状矿石是岩浆分离结晶过程中较快速度冷凝和就地硫化物熔离的结果;而网状矿石可能是硫化物熔体经深部熔离但未经充分的硫化物分离结晶作用贯入的产物;块状矿石成因定量模拟结果排除了R因子控制作用,不同矿体中块状矿石由不同程度的单硫化物固溶体(MSS)分离结晶所形成。

The authors studied the different types of ores in I and II mining areas of Jinchuan Ni——Cu——（PGE） sulfide deposit,and particularly the distribution pattern of platinum group elements.The ∑PGE in disseminated ores,net-textured ores and massive ores reduced gradually with the same trend in the mining area of orebodies Nos.24,1 and 2 from the west to the east.The sulfide melt of massive ores had fuller PGE differentiation than disseminated ores and net-textured ores.The distribution of platinum group elements in massive ores showed that they were controlled by sulfide melt fractional crystallization,and the separation of monosulfide solid solution（MSS）.The study showed that the disseminated ores were the results of rapid condensation and the in situ sulfide melting from the magma fractional crystallization.The net-textured ores formed by the sulfide melt fractional crystallization in the deep segregation.The study of quantitative simulation showed that the massive ores in different orebodies formed by the varying degrees of MSS fractional crystallization excluding the role control of R-factor.