全球铁氧化物铜金型(IOCG)矿床的3类大陆动力学背景与成矿模式  

Three types of continental geodynamics and metallogenic models for IOCG(Iron-oxide Copper Gold Deposits)from the global view

作　　者：方维萱[1,2] 柳玉龙[1,2] 张守林[1,2] 郭茂华[1,2] 

机构地区：[1]有色金属矿产地质调查中心北京资源勘查技术中心,北京100012 [2]Sinotex Mineral Exploration Chile Limitada,智利圣地亚哥

出　　处：《西北大学学报（自然科学版）》2009年第3期404-413,共10页Journal of Northwest University（Natural Science Edition）

基　　金：东川-易门铜矿山深部及外围勘查技术研究课题基金资助项目(2006BAB01B09);东川危机矿山基金资助项目(200553026);财政部海外风险勘探基金资助项目

摘　　要：目的对全球3类铁氧化物铜金型（IOCG，Iron—oxide Copper Gold Deposits）大陆动力学背景与成矿模式进行研究及总结。方法在对比全球典型IOCG矿床的元古代大陆裂谷盆地和流体叠加改造模式基础上，对智利洋壳俯冲背景下岛弧造山带的拉伸环境有关IOCG矿床和中国云南-四川IOCG矿床进行了实证研究。结果在智利与含铜金磁铁矿矿体密切相关的深成闪长岩类演化方向为闪长岩→辉长闪长岩→斜长岩＋闪石（玢）岩，闪长岩→花岗闪长岩＋石英闪长岩→花岗岩多与含铜金镜铁矿矿体有关。中国云南-四川铁钛氧化物铜金型（IOCG）属于第三类IOCG矿床成矿的大陆动力学背景，成矿大陆动力学过程为先期铁铜金氧化物型矿床形成于中元古代大陆裂谷盆地（无洋壳化），富铁钠质基性火山岩喷发形成铁氧化物铜金型和铁矿层，其上在碱性粗面质凝灰岩和含粗面凝灰质白云岩中赋存铜银矿层；在晋宁造山运动期后，在古地幔柱作用下，深源碱性闪长岩-辉长岩侵位发生高氧化叠加成矿，形成了碱性闪长岩-辉长岩中钛铁矿-钛磁铁矿矿（化）体，在围绕碱性闪长岩-辉长岩岩枝周边的隐爆角砾岩中形成了铁钛铜金氧化物型矿体。两期不同的大陆动力学背景与成矿作用叠加形成了东川超大型铁（钛）氧化物铜金型矿床，钛矿找矿潜力大且是今后找矿方向之一。结论全球铁氧化物铜金型（IOCG，Iron—oxide Copper Gold Deposits）形成于3类不同的大陆动力学背景，三种典型的成矿模式为一是以澳大利亚奥林匹克坝超大型铜-铁-金-铀-稀土元素矿床为代表，形成于元古代（19～14亿年）大陆裂谷盆地热水沉积和后期盆地流体叠加改造；二是南美（以智利为代表）IOCG矿床形成与洋壳俯冲背景下岛孤造山带，与深部地幔柱上升形成的岛弧造山带中局部拉伸环境密切有关；三是�Aim To study the different backgrounds of continental geodynamics for Iron-oxide Copper Gold Deposits （IOCG） with three different metallogenic models from the global view, although Iron-oxide copper gold deposits （IOCG） and their U-REE intergrowthing in useful components, one clan of the deposit associations have been paid much attentions by mining, exploration and geology sectors, and still ill-defined clan of mineralization styles of geotectonic settings and magmatic environments. Methods IOCG related to extensional environment of are orogenic belt by oceanic crust subduction in Chile and Peru and IOCG in Yunnan-Sichuan Provinces of China, two case studies have been completed, based on the Proterozoic rifted basin of continent and the basin-fluid-mixing model from the global view. Results It may be supposed that copper-gold-bearing magnetite deposits could be related to hypogene diorites with a evolution from diorite to grabbo-diorite, to anorthosite plus amphibolite porphyrite while copper-gold-bearing specularite deposits related to hypogene diorites with a evolution from diorite to granodiorite, to quartz diorite, and to granite. Iron-tianium-oxide-copper-gold deposits may be supposed to be the third type of continental geodynamics and metallogenic models for IOCG. In the Middle Proterozoie age, IOCG could be formed in continent-rifted basin without oceanization, and with IOCG and iron orebody beds produced by volcanic eruption of Fe-enriched,Na-basic magma while copper-silver orebody beds hosted in tuff and tuffaceous dolostone formed by trachytic magma. After Jinning orogenic movement, hypogene alkaline diorites and grabbe under mantle plume emplaced and high oxidation, resulted in the former orebodies superimposed and orebodies of ilmenite-ilmenomagnetite hosted in alkaline diorites and grabbo bodies. Iron-titanium-oxide copper gold deposits were hosted in eryptoexplosive breccia body around bodies of hypogene alkaline diorites and grabbo. Therefore, Iron-titanium-oxide copper gold deposits in Yun

关 键 词：铁氧化物铜金型(IOCG) 大陆动力学 地幔柱 铁(钛)氧化物铜金型矿床 云南东川 

分 类 号：P542.2[天文地球—构造地质学]