Morphology and Migration of Megabarchans on the Mali-Algeria Border

Previously, studies of barchans in Algeria have been limited to those close to In-Salah in the centre of the country and Mali has been entirely overlooked. This is primarily because the aeolian bedforms in these countries are predominantly linear dunes. However, 150-250km N-NE of Taoudenni, Mali one can find a number of barchans and megabarchans which straddle the Mali-Algeria border. To our knowledge, these dunes have not previously been studied. The widths of the dunes range from around 30m for the smallest barchans to 1.6km for the largest megabarchan, allowing us to test the robustness of scaling laws typically applied to barchans and the similarity between barchans and megabarchans. In this poster, we present preliminary analyses of the morphology and migration rates of the dunes measured using Google Earth imagery.