Hydrothermal phosphate geochronology: A way forward for dating gold mineralisation events in the Yilgarn craton of Western Australia

摘要

Research over the past 20 years has identified multiple gold mineralisation events in the Yilgarn craton of Western Australia. Orogenic gold mineralisation accounts for most economic gold deposits and is broadly coeval with very localized intrusion-related gold deposition. Local, early, minor syn-volcanic gold has been overprinted by orogenic gold and, in some deposits, there is evidence for reworking and remobilisa-tion of orogenic gold. Monazite and xenotime geochronology indicates that orogenic gold mineralisation was diachronous within a maximum of 30-40m.y. period between 2.66 and 2.62Ga. Further definition of the degree and extent of diachroneity requires more precise dates for gold deposition. Hydrothermal phosphates are identified at a number of deposits, in different terranes with different structural and metamorphic settings, and potentially provide a means for obtaining precise ages to allow such craton-wide comparisons.