Auriferous sediments of the Yilgarn Block, Western Australia

Gold-bearing sediments of mixed sedimentary-igneous composition, and associated largely with various basic volcanic rocks (greenstones), abound in the Archaean of the Yilgarn Block. In the Coolgardie district, where perhaps they are best developed, many important gold mines and several series of minor gold deposits occur in a few such horizons. Practically identical occurrences, even when highly metamorphosed, are also found elsewhere in greenstone belts-e.g. in the Southern Cross-Westonia-Yellowdine metamorphic zone.