Review of the application of isotopic studies to the genesis of Cu‐Au mineralisation at Olympic Dam and Au mineralisation at Porgera, the Tennant Creek district and Yilgarn Craton

This paper reviews the application of radiogenic isotopes to the study of four Cu‐U and Au deposits or deposit types in the Australasian region: Olympic Dam, Porgera, the Proterozoic Au deposits of the Tennant Creek district and the Archaean gold deposits of the Yilgarn Craton. In each case it has been possible to date the mineralisation and to correlate ore formation with a specific igneous event or stage in crustal evolution. In three cases it was also possible to use radiogenic isotopes to trace the source of the metal(s) or to constrain the fluid pathway. The results illustrate the power of radiogenic isotopes in ore‐genesis studies. At the Porgera gold deposit in Papua New Guinea K‐Ar and 39Ar/40Ar dating has shown that both the mineralisation, and the spatially associated Porgera Igneous Complex, have an age of ca 6 Ma. Sr and Pb isotopic tracing of the ore fluids indicate that these elements were derived from a mixed sedimentary‐igneous source, as might be expected for a large hydrothermal system d...