中国西部典型铜镍矿床亲铜元素特征对比

通过对喀拉通克、黄山东、金川和白马寨4个铜镍矿床亲铜元素特征进行比较,结果发现所有矿床具有相似的左倾原始地幔标准化配分模式和铂族元素明显亏损的共同特点;其亲铜元素质量分数却明显不同,铂族元素质量分数最高的金川铜镍矿床以Ni为主,喀拉通克矿床则表现为Cu占优势;矿床的初始岩浆为铂族元素不亏损的玄武质岩浆,应是地幔岩石较高程度部分熔融的产物;少量硫化物预先熔离是造成中国铜镍矿床成矿母岩浆亏损铂族元素和w(Cu)/w(Pd)远大于原始地幔(w(Cu)/w(Pd))的控制因素;不同程度(量)的硫化物熔离导致母岩浆中亲铜元素质量分数不同,R值低不是主要原因;早期发生硫饱和可能是铜镍矿床成矿的必要条件,成矿的关键可能在于新鲜岩浆的不断补给;少量硫化物预先熔离结合不含矿岩石亏损铂族元素,暗示这些矿区深部具有找矿潜力。

Comparisons for the Characteristics of Chalcophile Elements of Typical Cu-Ni Sulfide Deposits in Western China

Compared of the characteristics of chalcophile elements among Kalatongke, Huangshandong, Jinchuan and Baimazhai Cu-Ni sulfide deposits, the results show that it is similarly left leaning primary mantle normalized plots and notable depletion of platinum group element(PGE)in all deposits; mass fraction of chalcophile elements is significantly different, and it is mainly Ni in Jinchuan Cu-Ni deposit which is highest in mass fraction of PGE and mainly Cu in Kalatongke deposit; their primary magmas derived from the mantle by high degree partial melt maybe fertile in PGE; the initial magma of deposit is no loss basaltic magma of PGE, and is the product of higher partial melting of mantle rocks; a small quantity of sulfide pre-segregation is the control factor for PGE deficit of ore-forming primary magma of Cu-Ni deposits in China and the ratio of mass faction of Cu and Pd is much larger than that in primitive mantle; the lower R is not the main reason for the different mass faction of primary magma chalcophile elements which is resulted from different quantity sulfide segregation; sulfur saturation in the early stage may be necessary for the formation of Ni deposit, the key of formation of Ni deposit may be continuously supplement of fresh melts; the phenomenon that a small quantity of sulfide pre-segregation does not include mineral rock deficit PGE, indicates that the potentiality of exploration in the depth of these deposits is great.