青海唐古拉山北藏麻西孔岩浆活动与铜银多金属矿的关系

Relationship between magmatic activity of Zangmaxikong and the metallogenesis of Cu-Ag deposit in the north of Tanggula Mountain,Qinghai,China

对青海唐古拉山北藏麻西孔铜银矿区喜马拉雅期斑岩体通过野外观察，室内岩石化学、微量元素地球化学、稀土元素地球化学分析，研究斑岩体与铜银多金属矿的形成关系。斑岩体内，稀土元素总量高，轻稀土与重稀土之比值较大，为10．87～14．23，说明由下地壳局部熔融形成；形成年龄为38Ma，属碰撞后造山碱性花岗岩类。成矿与斑岩体关系密切。斑岩体中富Pb，Zn，Ag，Mo，Cu等，为成矿提供了重要的物质来源；成矿时代既晚于晚白垩世风火山群，又晚于斑岩体的侵入时间。在斑岩体的影响下，成矿元素向深部具有富积的趋势。

The Zangmaxikong Cu-Ag deposit is in Tanggula Mountain of Qinghai. The total REE of the Himalayan porphyry mass is high with a high ratio of LREE to HREE （between 10.87 and 14.23）. This represents that the porphyry mass was formed by the partial melt of lower crust. The age of the porphyrymass is 38 Ma. It belongs to post-orogeny akali-granite. The metallogenesis of the deposit has a close relation with the porphyry mass. The porphyry mass is rich in Pb, Zn, Ag, Mo and Cu, so, it which provides ore-forming materials for the metallogenesis. The metallogenetic epoch of the deposit is later than both the Late Cretaceous Fenghuoshan Group and the intrusion of the porphyry mass. Affected by the porphyry mass, the ore-forming elements become richer with depth.