Iron oxide copper-gold (IOCG) deposits are a comparatively recently recognized class of copper-gold deposits that are the focus of major exploration activity on several continents. This exploration interest has been prompted by the recognition that IOCG deposits have tonnages and grades similar to those found in porphyry Cu-Au systems (Fig. 1a), with major examples including Olympic Dam in South Australia, Candelaria in Chile and Salobo in Brazil. <...>