富宁基性岩区尾硐铜镍硫化物矿床矿化特征及矿床成因探讨

Disscussion on Mineralization Characteristics and Genesis of Cu-Ni Sulfide Deposits of Weidong in Funing Basic Rocks Area

通过对尾硐铜镍硫化物矿床矿区地质特征、矿体分布特征、矿床矿化特征和S同位素分析,认为该矿区内各岩相带呈渐变过渡关系,为同期侵入岩体,存在深部岩浆熔离作用。橄榄苏长辉长岩和辉长苏长岩是矿区内主要赋矿岩体。S同位素分析显示其主要为幔源原生硫;但也可能有硫通过地壳混染作用加入。含矿岩浆深部熔离和岩体侵位后的岩浆分异结晶是导致金属硫化物富集成矿的主要过程。岩浆期后热液的叠加改造作用对部分地段的成矿物质富集有重要贡献。

Through the analysis of geological characteristics of the Cu-Ni sulfide deposits in Weidong, together with its geological characteristics,distribution characteristics of ore-body , mineralization characteristics and S isotopes of the ore-body , this paper deems that there is a gradually transition relationship between every petrographical zonations. The magmatic rocks invaded in the same period and had a liquation in the deep. The ore-bodies are hosted by olivine norite gabbro and norite gabbro. S isotope analysis shows it is mainly primary sulfide from mantle , however it is possibly interfused by minute crust material . Deep-liquation and the latter fractional crystallization of the magma are the main ore-forming processes, they have resulted in metal sulfide enrichment and mineralization.Meanwhile, the superimposition and reformation of the magmatic hydrothermal had an important contribution to mineral enrichment in some parts.