An unusual occurrence of Pd, Pt, Au, Ag and Hg minerals in the Pilbara region of western Australia

A small high-grade occurrence of palladium, platinum, gold, silver, selenium and mercury at Copper Hills in the East Pilbara region of Western Australia exhibits a remarkable diversity of minerals and textures. Most of the mineralization occurs within a malachite-quartz host. with particularly high concentrations in malachite nodules. The primary minerals include a number of selenides, including oosterboschite, naumannite, chrisstanleyite. berzelianite, umangite, luberoite (?) and tiemannite, as well as some unidentified minerals. Other ore minerals include native gold, Dative silver and potarite, Oxidation of the Pd and Pt selenides has produced a range of fine-grained oxide mixtures. The Pd and Pt selenides and their oxidized products occur as fine-grained dispersions, commonly as arborescent fronds. and as larger inclusions in the malachite nodules. The native silver has been partially replaced by bromian chlorargyrite. The source of the mineralization is believed to have been acid, saline hydrothermal solutions charged With the precious metals, mercury, selenium and copper, Interaction of these solutions with dolomitic carbonate probably caused the precipitation of the minerals of economic interest.