Geochemical Features and Origin of the Gabbro in the Xiaonanshan Pt-Cu-Ni Deposit, Inner Mongolia
内蒙古小南山铂—铜—镍矿区辉长岩地球化学特征及成因

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.