Contact the author:
mary.bourke@geog.ox.ac.uk

Rivers in semi-arid central Australia that drain south from the MacDonnell Ranges tend to dissipate in the northwest trending longitudinal dunes of the Simpson Desert. The Todd, Finke and the Hale Rivers provide a suite of sites where the effect of flow magnitude and frequency on channel termini boundary dynamics can be examined. This paper considers fluvial-aeolian interaction at two scales and examines the facies and morphological response to modern- and paleo-floods.

High magnitude floods during the Late Pleistocene and Holocene events strongly influence the interaction and assemblage of fluvial, aeolian and lacustrine landforms along the desert margin. Typical effects include erosion of longitudinal dunes, emplacement of sandy-gravel bars, splays and clay pans. Quiescent periods permit aeolian processes to winnow flood surfaces, form climbing dunes on bedrock ridges and nourish the adjacent remnant Pleistocene dunes. Over longer time scales dunes have reformed across the abandoned flood channel. This paper will present the preliminary data (morphological, facies, SEM, OSL) on the two scales of interaction. Collectively these give insight into the geomorphic response of an aeolian system to perturbations by fluvial activity.