Sulphur and lead isotopes of gold and base metal mineralisation of the Yerrida and Bryah Basins – mineralisation characteristics and implications for exploration

Abstract

The Paleoproterozoic Yerrida, Bryah and Padbury Basins are located on the northern margin of the Archean Yilgarn Craton, and are host to orogenic gold (Peak Hill, Fortnum and Horseshoe), volcanic-hosted massive sulfide (VHMS; Horseshoe Lights, Red Bore, Monty and DeGrussa) and epithermal copper deposits (Thaduna) ultramafic, shear hosted copper mineralisation (Forrest-Wodger), as well as economic amounts of talc and manganese. Characterisation of the sulphur and lead isotope signatures of the different deposit types helps to distinguish the deposits types from one another (e.g. a DeGrussa-type VHMS deposit from a Thaduna-type Cu deposit), as well as the source of mineralising fluids in each deposit. With the exception of Horseshoe Lights, Pb isotopes have characteristically high μ values (10.8) throughout the Bryah Group. Combining this information with accurate geochronological information may provide guidance for exploration for gold and base metal mineralisation, not only in the Bryah and Yerrida, but also throughout the larger Capricorn Orogen.