The Proterozoic Curnamona Province extends across northeastern South Australia and western New South Wales, with exposures in the Willyama, Mount Painter and Mount Babbage Inliers, but much of it is obscured by younger sedimentary cover. Curnamona Province rocks comprise a late Palaeoproterozoic metasedimentary and metavolcanic succession (Willyama Supergroup) with some meta-intrusives and early Mesoproterozoic volcanics, sediments and granitoid intrusives. The Willyama Supergroup in South Australia is divided into the Olary and Broken Hill Domains on the basis of lithological and geophysical character, with a strong linear magnetic feature marking the boundary. A tentative lithostratigraphy has been established for the Olary Domain, in parallel with the Broken Hill Domain. Limited geochronology indicates broad contemporaneity, but the Olary Domain differs in the apparent dominance of shallow-water or evaporitic sediments, the relative paucity of volcanics, the presence of widespread metasomatism, particularly albitisation and associated brecciation, and abundant Mesoproterozoic granitoids. Current mapping of the Broken Hill Domain in South Australia has identified lithologies comparable with the Thorndale Composite Gneiss, Thackaringa Group, Broken Hill Group and Sundown Group. The Benagerie Ridge, known only from limited drilling, contains lower metamorphic grade metasediments consistent with the northwards decrease of grade observed in the Olary Domain. Further north on the ridge, essentially flat-lying Mesoproterozoic sediments and acid and basic volcanics may overlie Willyama Supergroup. The Willyama Inliers in South Australia have widespread base-metal, gold and uranium occurrences, although total production has been very small, except for the Radium Hill uranium mine. In the Broken Hill Domain, known mineralisation includes a copper sulphide resource at the Mutooroo Mine and several large, low-grade bodies of disseminated copper and zinc sulphides. The Olary Domain has numerous occurrences of copper, zinc, lead and gold associated with sulphidic, calc-silicate and albitic units. Copper and gold are also associated with stratabound quartz- magnetite bodies lower in the sequence. Discordant, epigenetic, base metal- and gold-bearing veins are also widespread in the Willyama Supergroup, related particularly to the retrogressive phase of the Mesoproterozoic Olarian Orogeny and to the Cambro-Ordovician Delamerian Orogeny. Significant intersections of copper, zinc, molybdenum and gold mineralisation have been found in ?Willyama Supergroup metasediments in the southern Benagerie Ridge. In general, the Curnamona Province is prospective for stratiform and stratabound lead- zinc and Olympic Dam and Cloncurry Belt style copper- gold(- uranium) mineralisation.
