Linear Dunes of the Kalahari

Abstract

The Kalahari of eastern and northern Namibia has many linear sand dunes, some of which have tuning-fork junctions. In the north they run from east to west, while in the south west they generally run from northwest to southeast. Many of these dunes are currently inactive and may be the product of formerly drier conditions. In the southwest of the Kalahari they occur in an area where the rainfall is less than 250 mm per annum whereas in the northern areas the present rainfall well exceeds 1,000 mm. Those in the southwest have mobile crests in dry, windy years. In recent years a number of studies have been undertaken on the ages of the Kalahari dunes using thermoluminescence (TL) or optically stimulated luminescence (OSL) dating techniques. These have shown that there have been a number of phases of dune accumulation over at least the last 186,000 years and that the dunes of the south west Kalahari have been partially active during both the Late Pleistocene and the Holocene. The chapter discusses the various models that have been proposed to account for the formation of linear dunes.