Degradation of linear dunes in Northwest Ngamiland, Botswana and the implications for luminescence dating of periods of aridity

The implications for luminescence dating of dune sands, to identify periods of aridity, are discussed. The dunes cannot simply be regarded as providing a stacked record of such periods. They are very old and much of the record is missing as a result of crest lowering. The chronostratigraphy includes degradational components which must be distinguished from those of construction. Bioturbation cannot be disregarded as a complication which overprints the luminescence signals.