Grain-size variation on dunes in the southwest Kalahari, southern Africa

Grain-size parameters (mean, standard deviation, skewness, and kurtosis) were determined for 83 sediment samples from six dune cross-profiles and one 28 km long-profile on dunes in the Southwest Kalahari Desert in Southern Africa. Although some studies elsewhere and previous studies in the Kalahari have reported significant grain-size variation over dune cross-profiles, data presented here show no systematic variation of grain-size parameters except that sediments from the crest of a dune are almost invariably better sorted (indicated by the standard deviation of the sample) than samples from the base, or plinth, of the dune. The proportion of fines < 63 micrometers) in plinth sediments is also greater than in crest samples. There is no significant trend in grain-size parameters along the length of a linear dune. This lack of significant pattern corresponds with similar findings for central Australian dunes. GeoRef Subject