金川铜镍硫化物矿床F_(1)断裂系统演化及其意义  

Evolution of F_(1) Fracture System in Jinchuan Cu-Ni Sulfide Deposit and its Significance

作　　者：李生栋 杨永春 艾启兴 达瑞 LI Shengdong;YANG Yongchun;AI Qixing;DA Rui(Forth Institute of Geological and Mineral Exploration of Gansu Provincial Bureau of Geology and Mineral Resources,Jiuquan 735000,Gansu,China;Nickel Cobalt Research and Design Institute,Jinchuan Group.,Ltd.,Jinchang 737104,Gansu,China)

机构地区：[1]甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000 [2]金川集团股份有限公司镍钴研究设计院,甘肃金昌737104

出　　处：《大地构造与成矿学》2022年第1期63-76,共14页Geotectonica et Metallogenia

基　　金：金川集团股份有限公司项目(金科地2020-05)资助。

摘　　要：金川铜镍硫化物矿区构造活动频繁且复杂,查明矿区构造规律,是实现深部找矿突破的必经途径之一。文章在充分挖掘区域及以往勘查资料的基础上,通过野外实地调查,对矿区内成矿后断裂系统--F_(1)断裂系统分析研究,发现F_(1)断层角砾岩呈棱角状,深部产状北倾,断层发育在龙首山岩群一侧,无法仅靠现今的叠置关系解释F_(1)的演化。结合潮水盆地研究成果,总结出F_(1)与潮水盆地同步演化和发展的特征和历程:早-中侏罗世断陷成盆期,F_(1)形成同生正断层,后期受青藏高原隆起产生的水平挤压,改造为左行逆断层;其他断裂构造是F_(1)的派生(次生)断裂,在统一的应力场作用下形成,具内在的成生联系,F_(8)是F_(1)的分支断裂,为“入”字型构造。研究表明,Ⅰ、Ⅱ、Ⅳ矿区地层及岩矿体,浅部主要通过F_(1)反转及次级断裂的形式,由南南西向北北东发生位移,产状由西向东逐渐变缓,岩石完整性受到破坏;深部超基性岩体则基本保持了其原始侵位形态,受影响较小;岩矿体深部连续延伸地段为找矿有利部位,对深部勘查具重要指导意义。The Jinchuan deposit is the third largest Cu-Ni sulfide deposit in the world.With the continuous consumption of the proven reserves,the deep resource exploration become crucial for the sustainable development and utilization.The mining area experienced multiphase and complicated tectonic activities,which leads to the highly controversial interpretations of the evolution of the largest F_(1) fault in the mining area.Some researchers believe that F_(1) is a rock-and ore-controlling fault,which was formed in the Lüliang period,while the others argue that F_(1) is a nappe structure,which is a SW-dipped listric fault in the upper crust.Therefore,delineating the structural controls on the ore mineralization is an essential step to realize a breakthrough of deep prospecting.On the basis of fully mining of the previous exploration data and geophysical exploration achievements,combined with the development and evolution of regional structures,the post-metallogenic F_(1) fracture system in the mining area is systematically analyzed and studied through field investigation.It is found that the structural breccia of the F_(1) fault zone is angular to subangular,with argillaceous cementation,and comes mainly from the Longshoushan Rock Group along with the Quaternary sandy gravel and Neogene sandstone and conglomerate.Two-dimensional seismic profile and other geophysical results show that the occurrence of the F_(1)fault is steep in the deep part,so it is difficult to explain this phenomenon reasonably and reveal its internal genetic relationship even though it is clear that the F_(1)fault is a reverse fault according to the superposition relationship.Combined with the research results of the Chaoshui Basin,the authors firstly proposed a possible mechanism for the formation and evolution of the F_(1)fracture system and its genetic relationship with the Chaoshui Basin evolution.1)The F_(1)fault and the Chaoshui Basin evolved synchronously,and a series of contemporaneous normal faults were formed in the basin during the early an

关 键 词：F_(1)断裂系统 潮水盆地 断层反转 “入”字型构造 铜镍矿床 金川 

分 类 号：P542[天文地球—构造地质学]