LAUSR

Abstract The Cooloola Sand Mass is a large coastal dune field situated in southeast Queensland, Australia and is part of a much larger system of coastal dune fields, including the world's largest sand Island, Fraser Island, as well as Moreton Island and Stradbroke Island. Cooloola is characterised by a sequence of onlapping, parabolic dune units that have been emplaced episodically over the Pleistocene and Holocene. The tectonically stable coastline of SE Queensland is an ideal area to study the driving mechanisms of coastal dune development, as sea level variability is driven primarily by glacial eustasy. Geomorphic and chronostratigraphic analyses have identified seven major periods of dune activity with the earliest phase of deposition occurring ca. 800 ka. Subsequent periods of dune emplacement date to about ca. 150 ka, 110 ka, 10–6 ka, 5–3.5 ka, ca. 2 ka and 0.4–0.2 ka. The Holocene dune activity coincides with the last stages of post-glacial marine transgression and suggests these large parabolic dunes formed in response to rising sea levels. It is likely that this pattern is consistent through the Pleistocene, and the MIS 5 interglacial period is also recorded. For earlier events the large absolute errors on the ages make interpretation difficult. There is a notable absence of OSL ages dating to the Last Glacial Maximum and no ages that are unambiguously associated with lowstand periods. This is most likely because the coast would have been 60 km offshore of its current position during lowstands, limiting sediment supply and wind energy at the modern coast. These results provide strong evidence that coastal dune fields in SE Australia are predominantly emplaced during sea-level rise, as originally proposed in the Cooper-Thom model.