甘肃金川硫化铜镍矿床地质特征

金川矿床是我国知名的硫化铜镍矿床。它由四个矿区组成(图1)。该矿床除含有丰富的镍、铜外,还含有一些贵金属及钴等,为一含多种金属元素的硫化物矿床。本文是笔者在对该区多年积累的大量地质资料进行分析研究的基础上写成的,谬误之处,敬请指正。一、区域地质背景矿床位于阿拉善台块南西边缘,龙首山隆起东段北东侧深断裂的上盘(即南西侧)。龙首山基底为前长城系,盖层为长城—蓟县系和震旦系。前长城系内的八个伟晶花岗岩之云母样的同位素年龄为16.57—17.41亿年,一个片麻状花岗岩之白云母样的同位素年龄为17.86亿年。故这套深变质岩系的年龄应不小于18亿年。

Eological Characteristics Of The Jinchuan Cu-Ni Sulfide Deposit In Gansu Province

The Jinchuan mine is a Cu-Ni sulfide deposit of remarkable economic significance. ln addition to abundant major elements Cu and Ni, it has quite a lot of valuable associated elements. This deposit has many unique characteristics different form other deposits of the same type both at home and abroad in geologic setting and mineralizations. For instance, it has relatively young metallogenic epochs and multiple rock-forming phases and stages; lithologically, there are merely plagioclase-bearing ultrabasic rocks occurring as dykes and characterized by especially good ore potential; the deposit is of multiple ore-forming stages and geneses, with the main type being deep-seated magmatic differentiation by liquation-ore magma injection orebodies, accompanied by commercial contact-metasomatic orebodies related to ultrabasic bodies and hydrothermal-superimposed Pt (Pd) orebodies or occurrences; potassium-bearing nickel minerals which have never been reported are observed. The deposit occurs at the southeastern marginal uplift of the Alxa platform, and the ore-bearing ultrabasic rocks with K-Ar isotopic ages of 1510 Ma and 1530 Ma are within high-grade metamorphic rocks of Archaeozoic Baijiazuizi Formation. Orebodies of this deposit are all genetically associated with this ultrabasic body. Mineralization can be divided into three stages: magmatic, pneumato-hydrothermal and hydrothermal stages. Orebodies might be grouped mto five types: magmatic differentiation by liquation orebodies, deep-seated magmatic differentiation by liquation-ore magma injection orebodies, late stage ore magma injection and contact-metasomatic orebodies, and hydrothermal-superimposed orebodies or occurrences.