Barrier Stratigraphy on the Macrotidal Central Queensland Coastline, Australia

Abstract

The morphostratigraphyof two macrotidal, low energy, sandy barrier systems on the central Queensland coastlme (Australia) were investigated. The barriers contain transgressive and regressive sequences and are underlain by a continuous layer of basal transgressive mud, which is exposed at approximately 10 m water depth. The thickness of the macrotidal barrier sequences is 8-12 m, and the limited vertical extent of the barriers is ascribed to the low wave energy level (wave height < 0.6 m) and the gentle gradient of the continental shelf (1/1,000) off the central Queensland coastline. Offshore sediment and seismic data indicate an inner shelf depleted of Holocene sediments, with a pre-Holocene substratum outcropping in many places. The stratigraphy of both barrier systems suggests that (a) sea level was about 2 m higher than present at the maximum postglacial marine transgression (PMT) and (b) a tidal window may have occurred close to PMT.