Integrated Triassic sediment routing along eastern Gondwana (Australia)

Matthew Scipione , Romain Vaucher , Eric Roberts, Alex J McCoy-West, Joan Esterle, Ashten Turner, Espen Knutsen

Triassic continental sedimentary basins along the eastern margin of Gondwana record drainage reorganisation and sediment routing, but provenance links among adjacent basins remain uncertain. This study integrates detrital zircon U–Pb data and sandstone petrography from the Triassic Rewan Group and Clematis Group of the northern Bowen Basin with published palaeocurrent constraints and compares these with published Triassic detrital zircon datasets from the Galilee Basin and the Gympie Terrane. Rewan Group zircon spectra are dominated by Middle Triassic grains (ca. 245 Ma) with persistent Carboniferous components. Sagittarius Sandstone and Arcadia Formation samples plot close together in a multidimensional scaling ordination of Wasserstein-2 distances, indicating similar age mixtures across the sampled Rewan Group depocentres. Short crystallisation-to-deposition age gaps and feldspar-poor, lithic-rich petrography are consistent with sustained volcaniclastic input from the eastern Tasmanide margin during Rewan Group deposition. Clematis Group spectra are more variable, contain fewer Triassic zircons, and include a larger proportion of grains older than ca. 400 Ma. More quartzose petrography and longer crystallisation-to-deposition age gaps suggest greater continental-interior input and/or increased recycling during later Triassic deposition. Regional comparisons place Rewan Group samples with the Bandanna Formation and Gympie Terrane units, whereas Clematis Group samples are closer to the Warang Sandstone and Porcupine Gorge Formation. Moolayember Formation reference spectra shift back towards a Rewan Group-like signal, suggesting that the Clematis Group provenance shift may have been temporally limited. These results provide a quantitative basis for testing basin connectivity and for linking changes in provenance to sediment routing within retroarc foreland systems.