Present day lunette sediment cycling at Witpan in the arid southwestern Kalahari Desert

Witpan is a pan depression in the southwestern Kalahari Desert. The pan fringing lunette dune has a number of notable characteristics: a highly active crest; the lower lunette pediment is cemented; and the lower lunette supports a highly developed and active gully system. Geomorphological and sedimentological considerations are used to evaluate the interaction of wind and water in shaping contemporary lunette processes. It is considered that like other pans in the area, groundwater activity influences pan floor sediment availability and transport, that the present highly sea-sonal climatic regime permits the interaction of aeolian transport of sediment to the dune and its return to the pan floor by water during storm events, creating a cycling process favoured by sedimentary properties that promote surface runoff.