内蒙古小南山-铂-铜-镍矿区辉长岩地球化学特征及成因

Geochemical Features and Origin of the Gabbro in the Xiaonanshan Pt-Cu Ni Deposit,Inner Mongolia

小南山是华北地台北缘重要的铂 铜 镍矿床之一 ,其赋矿围岩地球化学研究为国内外地质学家所关注。本文对赋矿辉长岩及相关蚀变岩进行了主元素、稀土元素和微量元素地球化学研究。研究结果表明 ,含矿的辉长岩属于铁质基性岩 ,其原岩为幔源的大陆拉斑玄武岩。辉长岩在次闪石化过程中有大量的成矿物质被萃取出来 。

Xiaonanshan is one of the most important Pt Cu Ni deposits on the northern margin of the North China platform. There are two types of orebodies: one is the magmatic liquation type and occurs within the gabbro, and the other is the hydrothermal type and occurs within marl. Based on detailed studies of main elements, rare earth elements and trace elements of the ore bearing gabbro and associated altered rocks, it is suggested that the gabbro belongs to the ferri basic rocks, and its protoliths were continental tholeiite derived from the mantle. During the uralitization, lots of ore forming materials were extracted from the gabbro. Therefore, the uralitization might have played an important role in controlling the formation of late stage hydrothermal orebodies.