Age of desert dunes near Birdsville, southwest Queensland

Abstract

A mild controversy has arisen concerning the age of sand ridges in the eastern Simpson Desert, around Birdsville. Stratigraphic evidence indicates a Holocene age, but thermoluminescence (TL) dating of two sand samples from the area gave ages of about 34 ka and almost 78 ka (Wollongong laboratory). In an attempt to resolve the difficulty, sand samples were collected and dated by optically stimulated luminescence (OSL) from a dune east of Birdsville. Though low, the dune is fully exposed in section so that basal sand as well as sediment from the substrate below the gibber were sampled. The substrate gave dates of 36 ka, the basal sand about 10 ka, and sand from higher levels about 9 ka. No younger sand was present and the dune is construed as the clay-cemented core of a dune from which loose sand has been stripped by the wind. Samples of uncemented sand from the crests and flanks of higher dunes, and from a clayey lee-side mound in the same area gave dates around 1 ka or less. © 2001 Elsevier Science Ltd.