中国铁氧化物-铜-金(IOCG)矿床的基本特征及研究进展  

An overview on the characteristics and origin of iron-oxide copper gold(IOCG) deposits in China

作　　者：陈伟 赵新福[2] 李晓春 周美夫[3] CHEN Wei;ZHAO XinFu;LI XiaoChun;ZHOU MeiFu(Stage Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China;Department of Earth Sciences,University of Hong Kong,Hong Kong,China)

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵阳550081 [2]中国地质大学资源学院,武汉430074 [3]香港大学地球科学系

出　　处：《岩石学报》2019年第1期99-118,共20页Acta Petrologica Sinica

基　　金：国家重点研发计划(2017YFC0602302);国家自然科学基金项目(41673048;41472068);中国科学院前沿科学重点研究项目(QYZDB-SSW-DQC008)联合资助

摘　　要：铁氧化物-铜-金(Iron Oxide-Copper-Gold,IOCG)矿床是Hitzman et al.(1992)提出的一个新矿床类型。该概念的提出与澳大利亚Olympic Dam超大型矿床的发现有关,一定程度上促进了世界上同类新矿床的发现,引起工业界和学术界的广泛关注。中国IOCG矿床的研究起步较晚,在IOCG概念提出后很长一段时间内,并没有国内外公认的IOCG矿床报道。近年来,通过对一些Fe-Cu矿床的实例研究,目前已初步确立中国西南康滇地区、东准噶尔北缘和东天山阿齐山-雅满苏等Fe-Cu成矿带具有类似于IOCG的成矿特征,并且在矿床形成时代、机制及构造背景等成因问题上取得诸多进展。成矿时代上,康滇Fe-Cu成矿省形成于元古代,包括有～1. 65和～1. 0Ga两期主成矿事件,分别对应于区域上的两期板内岩浆作用,说明Fe-Cu矿化与大陆裂谷背景相关。东准噶尔北缘和东天山阿齐山-雅满苏成矿带均形成于古生代,分别为295～320Ma和～380Ma,被认为可能与陆缘盆地闭合有关。三个成矿带中Fe-Cu矿床围岩均为火山-沉积地层、均具有早期Fe矿化和晚期Cu矿化为主的特征且大部分矿床与同期侵入岩体没有明显空间关系,但在蚀变矿物组合及金属元素富集程度、流体特征等方面仍存在一些差别。例如康滇成矿省的蚀变组合以成矿前区域Na化、Fe矿化期Fe-Na-(Ca)化及铜矿化期K化和碳酸盐化等为特点;矿体在空间上常与大小不等的热液角砾岩筒共生;各矿床不同程度地富集REE、Mo、Au、Co等金属;成矿流体上早期以高温、中高盐度的岩浆热液为主,而成矿晚期则有更多非岩浆流体(盆地水、地层水或大气降水等)的加入。这些特点与世界上典型的IOCG矿床(特别是前寒武纪矿床)基本一致,因此目前为止,康滇成矿省作为中国的典型IOCG矿床而受国内外认可的程度相对较高。东准噶尔北缘与东天山阿齐山-雅满苏成矿带矿化特征较为相似,�Iron oxide copper-gold( IOCG) deposits are a new group of hydrothermal Fe-Cu deposits,the concept of which was recently proposed by Hitzman et al.( 1992) initially due to the discovery of the giant Olympic Dam Fe-Cu-U deposit in Australia. Such a definition has triggered new discoveries of similar deposits worldwide,thus attracting extensive concerns from academy and industry societies. Researches on IOCG deposits in China are rare in past few years,and no typical IOCG deposits were reported for a long time until recent. Recent case studies on some Fe-Cu deposits in China have revealed several potential IOCG provinces in China,including the Kangdian in SW China,northern margin of East Junggar and Aqishan-Yamansu( Eastern Tianshan) Fe-Cu belts in East Tianshan,NW China. The Fe-Cu deposits in the Kangdian province are Proterozoic in ages,but involving two mineralization events of ~1. 65 Ga and ~1. 0 Ga. Both events are synchronous with within-plate rifting-related magmatism in the region,and thus were considered to be related to continental rifting setting. On the other hand,the Fe-Cu deposits in both the northern margin of Eastern Junggar and Aqishan-Yamansu( Eastern Tianshan) Fe-Cu belts are Plaeozoic in ages,forming at ~380 Ma and 295~320 Ma,respectively.Geochemical studies on the coeval magmatism in both belts indicated that the Fe-Cu deposits in the northern margin of Eastern Junggar and Aqishan-Yamansu belts have formed during closure of rifting basins in continental margins. The Fe-Cu deposits in the three belts are broadly similar in terms of mineralization styles,such as the hosting rocks as volcanic-sedimentary sequences,a paragenetic sequence of early Fe and late Cu mineralization stages,and no clearly spatial relationships of ore bodies with synchronous intrusions.However,there are also minor differences in terms of alteration and metal assemblages. For example,compared to the other two belts,Fe-Cu deposits in the Kangdian Fe-Cu province were characterized by pre-ore,regional Na alteration,Fe-Na-( Ca) a

关 键 词：IOCG矿床 康滇成矿省 东准噶尔北缘成矿带 东天山阿齐山-雅满苏成矿带 

分 类 号：P611[天文地球—矿床学]