氧化铁型铜－金(IOCG)矿床的地质特征、成因机理与找矿模型

Geological features,ore-forming processes and prospecting model of iron oxide-copper-gold deposits

氧化铁型铜-金(IOCG)矿床主要指那些铁氧化物含量大于20%的铜-金矿床,其成矿理论研究和找矿勘查倍受国内外地质学家所关注。笔者对国外重要IOCG矿床地质特征进行了总结,同时,对其成矿作用和找矿模型进行了讨论。初步研究结果表明,尽管单一铁矿床和IOCG矿床同属氧化型成矿体系,但是它们分别为该体系的两个端元组分,因此,不应该将单一铁矿床列入IOCG矿床之列。另外,根据对澳大利亚IOCG矿床野外考察时所获经验,笔者对中国新疆、云南、安徽、四川和海南等省(区)铁-铜矿床的产出环境、地质特征和成矿作用进行了对比分析,其中雅满苏、天湖、老山口、乔夏哈拉、大红山、鹅头厂、拉拉、大小岭和石碌矿床与典型IOCG矿床存在许多相似之处,它们是否可划属为IOCG矿床尚值得进一步工作。

In general, the copper-gold （-silver-niobium-platinum group element-rare earth element-uranium） deposits that contain iron oxides （magnetite and/or hematite） more than 20% are called iron oxide copper-gold （IOCG） deposits. The geological features, metallogenic mechanism and prospecting models have been extensively and intensively studied both at home and abroad. The geology of the major IOCG deposits worldwide has been summarized in this paper. Meanwhile, the ore-forming processes and prospecting criteria on these typical IOCG deposits have also been discussed. Our preliminary studies show that both iron-only deposit and IOCG deposit belong to the oxide iron ore-forming system, but they are the end-member of the system, respectively. Therefore, the iron-only deposits should not be listed in the IOCG family at present. Based on our knowledge obtained from the geological field investigation on the Australian typical IOCG deposits, the tectonic setting and geological features of the iron-copper deposits occurring in Xinjiang, Yunnan, Sichuan,Anhui and Hainan provinces （or autonomous regions） have been analyzed. Among these studied deposits, the Yamansu, Tianhu, Laoshankou, Qiaoxiahala, Dahongshan, Etouchang, Daxiaoling, Lala and Shilu deposits show a lot of similarities to these typical IOCG deposits. To demonstrate the genetic type and ore-forming mechanism of these iron-copper deposits, the comprehensive studies will be needed.