Stratigraphical evidence shows that the Simpson Desert dunefield is of latest Pleistocene-Holocene age. The dunes are still active. TL dating of dunes around Birsdsville however gave Late Pleistocene ages (c. 78,000 and c. 34,000 years). To test this apparent anomaly a site east of Birsdsville was sampled. It is exposed to the dune base and beyond. Internal structures are readily discernible. OSLanalysis gave dates of 8800 years at the crest and 10,000 years at the base. The underlying alluvium is some 36,000 years old. The upper zones of dunes west of Birdsville gave ages of 1000 years or less. Samples from a source-bordering dune were dated at 1000-1300 years. Dunes formed in the lee of such transverse forms are obviously younger, for they developed because of the obstacle. The implications of these dates are discussed as are questions of dune colour and size.
