Geology and geochronology of the Two-Thirty prospect, Northparkes district, NSW

The Northparkes district, central New South Wales, hosts several economic Cu–Au deposits associated with discrete, thin, porphyry intrusive complexes emplaced in the Late Ordovician during formation of Macquarie Arc. recently discovered Two-Thirty Cu–Au–(Mo) prospect is a mineralised magmatic–hydrothermal breccia complex that hosted by moderately east-dipping Goonumbla Volcanic Complex on western limb Milpose Syncline ?15 km south district. Generation interpreted to be related 448.0 ± 4.4 Ma emplacement porphyry. However, Re–Os dating molybdenite from indicates potential for ca 440 mineralising event has similar timing mineralisation discovery important implications exploration district and broader only second known occurrence magmatic-hydrothermal breccia-hosted within Arc, other being Cadia Quarry. Mineralisation at potentially older than deposits, younger epithermal calc-alkaline Cowal, Marsden Ridgeway.KEY POINTS:The polyphase (Mo).The first significant found district.U–Pb zircon crystallisation ages causative intrusion pre-date Northparkes.Re–Os dates are coeval syn-mineralisation Northparkes, supporting model periodic release melts fluids underlying magma chambers