New chronological evidence for the nature and timing of linear dune development in the southwest Kalahari Desert

Abstract

The age of the linear dunes in the southwest Kalahari Desert has not previously been directly established. By applying the optical dating method to samples from the dunefield a number of questions relating to the timing and nature of linear dune development are addressed. The last major period of simple linear dune development occurred 17,000–10,000 years ago, probably from the reworking of earlier aeolian sediments. Dune emplacement occurred under more arid, probably windier, conditions than those prevailing today, which are only responsible for episodic surficial dune sand movement. As well as simple linear dunes, the dunefield also contains more complex linear dune patterns. Samples from one area in the eastern dunefield demonstrate that multi-phase development is more probable for complex dune patterns as opposed to single-phase evolution under a complex wind regime.