金川铜镍硫化物矿床岩浆通道系统的成矿模式

Metallogenic Model of Magma Conduit System of Jinchuan Cu-Ni Sulfide Deposit

金川矿床是目前世界第三大在采铜镍硫化物矿床,其成岩成矿过程及侵位机制一直存在争议。近年来,岩浆通道系统成矿被越来越多的人所接受,正是由于岩浆通道系统这样特殊的开放系统为"小岩体成大矿"提供了成矿条件。通过对岩体的形态,以及岩体与围岩接触处的宏观和地球化学特征的研究,指出在岩体侵入前存在一组由F1、F2等拆离断层所组成的正断层系统,为金川岩体的控矿构造,且是与上一级岩浆房贯通的岩浆通道。而对不同矿体Cu、Ni及铂族元素变化趋势的总结和Ⅰ6行富铜隐伏矿体、Ⅱ2号矿体33-41行特富矿的研究,发现Ⅰ24号、Ⅱ1号与Ⅱ2号矿体的矿浆分别由两个不同的岩浆通道形成,指出了岩浆通道的可能产出位置,探讨金川铜镍硫化物矿床的岩浆通道系统成矿模型。

Jinchuan deposit is the third largest mining magmatic sulfide Ni-Cu deposit in the world.Its ore- forming process and emplacement mechanism have been debated since it discovered.Currently,Metallogenic system of magma conduit system has been increasingly accepted by geologists,because of the theory that o- pening magma conduit system provides ore-forming conditions,called＂Small intrusions form large deposits＂.In this paper,Metallogenic model of magma conduit system of Jinchuan Cu-Ni sulfide deposit is discussed combined with previous research.Intrusion＇s shape,macroscopic and geochemical characteristics of contact belts between igeous rock and wallrock,reflect that there is a normal fault system comprised of Detachment fault F1 and F2,etc.,before the ultrabasic pluton emplaced,Which is ore-controlling faults of Jinchuan de- posit,and the magma conduit interlinked with foot magma chamber.Summarizing the variation of Cu,Ni,platinum group grades in different ore bodies,and research on the line-6 copper（PGE）-rich orebody and NO.2 orebody line-33-41 extremely rich ore,show that the ore magma ofⅠ24,Ⅱ1 and Ⅱ2 orebody are formed by different magma conduits,respectively.Then we propose the possible output position of magma channel and summarize the mineralization model of this deposit.