Early Permian sediment provenance and paleogeographic reconstructions in southeastern Gondwana using detrital zircon geochronology (Northern Perth Basin, Western Australia)

Abstract

The Perth Basin (Western Australia) forms part of a north-trending belt of intracratonic rift basins that initiated in southeastern Gondwana in the Late Paleozoic. Existing provenance studies have highlighted the dominance of Proterozoic zircons derived from southerly terranes such as the Albany-Fraser Orogen, Leeuwin Complex, and more distant provinces in East Antarctica, with limited input from the adjacent Archean Western Australian Craton. New U-Pb geochronology data were acquired using a Sensitive High Resolution Ion Microprobe (SHRIMP II) on detrital zircons from Lower Permian formations exposed in the northeastern Perth Basin. In contrast to previous studies, Archean zircons, showing fine oscillatory zoning, dominate the age spectra with up to 90% grains ranging between 3.0 and 2.6Ga, indicating that granitic parent rocks of the adjacent craton were a major sediment source during the Early Permian. A minor Paleoproterozoic age population from the Gascoyne Complex of the Capricorn Orogen was likely transported southward and dispersed in the basin by a combination of longshore drift and tidal currents. Meso- and Neoproterozoic detritus became prominent only from the middle Artinskian, and may relate to the establishment of large northward-flowing river systems draining the Albany-Fraser province, the Prydz-Leeuwin Belt, and/or the Wilkes Land in East Antarctica. This study shows that integrating depositional processes and stratigraphic evolution of sedimentary formations with provenance analysis can enhance reconstruction of dispersal pathways to and within basins.