我国一些铜镍硫化物矿床主要金属矿物的特征

镍、铜共生的铜镍硫化物矿床是镍矿也是铜矿的重要矿床类型。磁黄铁矿，镍黄铁矿、黄铜矿是这类矿床的主要金属矿物。它们的某些矿物学特征，特别是微量元素Ｃｏ／Ｎｉ比值，与其他铜矿类型明显不同，这三种矿物组成不同于任何其他铜矿类型的典型矿物共生组合， 形成特殊的海绵损铁状、球滴状构造。

Characteristics of Main Metallic Minerals in Some Copper-Nickel Sulfide Deposits of China

Copper-nickel sulfide deposits are mainly distributed in epicontinental stre-tching zones,continental rift zones and fault depression troughs.Ore-forming intrusive bodies are ferruginous ultrabasic rocks and basic rocks,exhibiting obvious mantle source characteristics.Pyrrhotite,Pentlandite and chalcopyrite are main metallic minerals in cop-per-nickel sulfide deposits. Pyrrhotite includes three variants (troilite, hexa-gonal pyrrhotite,and monoclinic pyrrhotite) and shows varied superstructural types. Chalcopyrite and pyrrhotite have high Co and Ni content and low Co/Ni ratios (Co/Ni<1),being obviously different from these two minerals in other types of copper deposits. Pentlandite commonly contains such minor elements as Co,Ag and Cu, and sometimes has high content of Ag and Cu, even forming Ag-pentlandite and Cu pentlandite Pyrrhotite-pentlandite-chalcopyrite constitutes basic minezal assemblage of this type of ore deposits, and this is obviously different from typical mineral assemblages of other types of copper deposits. With the advance of minerali-zation,these minerals can form different ore types. As a rule, pyrrhotite is richest in ore,whereas the amounts of pentlandite and chalcopyrite are related to the content of Ni and Cu in ore deposits.