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

Abstract：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.