The majority of deposits are hosted by metamorphosed Palaeoproterozoic supracrustal rocks of varying age, composition and metamorphic grade. Mineralisation was localised by a range of brittle-ductile and brittle structures and produced vein, stockwork, breccia and replacement orebodies. Variations of fluid chemistry, host rocks and physical conditions produced mineralogically-diverse alteration zones, varying Cu:Au ratios, many different minor element associations, and inconsistent spatial relationships between magnetite and ore metals.

Regional-scale alteration systems are dominated by Na-(Fe-Ca)-rich assemblages in which the most characteristic mineral is albite. Most of the ore deposits are specifically associated with pre- to synmineralisation alteration assemblages composed of medium to high temperature K-Fe-(Ca-Mg)-rich minerals together with late-stage parageneses containing carbonates. The deposits formed in deep-seated (> 5km) environments by a variety of different geochemical mechanisms from complex H2O-CO2±CH4±N2-salt fluids of magmatic and/or metamorphic derivation .