Current models for metamorphic fluid flow provide a framework for understanding the setting and genesis of Australian Precambrian ore deposits thought to have formed during metamorphism. Ideal conditions for formation of large metamorphogenic ores are a) an initial phase of metals dissolution by penetrative flow of devolatilisation, surface or igneous fluids along pathways of constant or increasing temperature, because channelised fluid flow will not normally provide the required metal volumes or transport continuity to subsequently form large ore deposits, and b) a subsequent phase of channelised fluid flow, particularly during retrogression or fluid mixing where temperature or fluid chemical changes combine with rapid fluctuations in fluid pressure accompanying dilatancy pumping. Protracted thermal histories and the identification of multiple hydrothermal events in major mineralised blocks (Yilgarn, Mt Isa, Broken Hill) provide some weight for multi-stage ore enesis models, particularly for giant ore deposits. Despite continuing uncertainty about the tectonic setting of many major mineral provinces, intra-plate orogeny, particularly in the Palaeoproterozoic and Mesoproterozoic, appears to provide the necessary conditions for development of rich mineral provinces. Such orogenies have the right combinations of temperature- pressure history, fluid evolution and magma generation to provide optimum conditions for ore genesis. A common feature to intracratonic belts of this age is an early phase of crustal extension following or synchronous with mafic magma underplating, and this early underplating may be the ultimate reason for primary metals enrichment. However, the subsequent path history of metals culminating in ore deposition is still controversial and poorly understood for most Australia Precambrian terrains.
