Grain size characteristics of Namib Desert linear dunes

Abstract

The results of a systematic sampling of linear dunes in the northern Namib sand sea show that they are composed of two distinct groups of sands: a fine, well-sorted, near-symmetrical crest and slip face population, and a coarse, moderately sorted, positively skewed plinth population. These may be explained in terms of the aeolian sorting processes operative on the dunes, which involve differential rates of movement of creep and saltation load on windward flanks and avalanching on leeward slopes, leading to the concentration of coarse sands towards the dune base.