Provenance of detrital zircons on the Western Australia coastline - Implications for the geologic history of the Perth basin and denudation of the Yilgarn craton

The age distributions of four detrital zircon samples from Western Australi a placer deposits are found to be dominated by Neoproterozoic and Mesoprote rozic ages; this outcome challenges a long-held assumption about derivation from the nearby Archean Yilgarn craton. The dominant ages are consistent w ith derivation from Proterozoic orogens marginal to the Yilgarn craton, inc luding the Pinjarra orogen and Leeuwin block to the west and the Albany-Fra ser orogen to the south. The results suggest that these marginal orogens we re preferentially uplifted in the Jurassic-Cretaceous rifting event that fo rmed the Perth basin and subsequently dominated the sedimentary contributio n to this basin. These sediments have since been recycled to form the moder n beach-sand placer deposits that reflect their non-Archean provenance desp ite proximity to the Yilgarn craton. The lack of a sedimentary contribution from the Yilgarn craton to the Perth basin implies that peneplanation was complete before the Mesozoic and that denudation rates have been minimal ev er since.