Kalahari Desert northwest, forming marshes that are rich in wildlife. Ancient dry riverbeds—called omuramba—traverse the central northern reaches of the Kalahari and provide standing pools of water during the rainy season. A semi-desert, with huge tracts of excellent grazing after good rains, the Kalahari supports more animals and plants than a true desert, such as the Namib Desert to the west. There are small amounts of rainfall and the summer temperature is very high. The driest areas usually receive of rain per year, and the wettest just a little over . The surrounding Kalahari Basin covers over extending further into Botswana, Namibia
Kalahari Craton Archaean-Palaeoproterozoic core of the craton is called the Proto-Kalahari Craton. This core plus accreted Mesoproterozoic crust and dispersed non-African fragments compose the Kalahari Craton. Before the Pan-African Orogeny, the Kalahari Craton was much larger than it is today, but its sutures and therefore its extent are difficult to locate due to later overprinting. The Kaapvaal Craton, Zimbabwe Craton, and Limpopo Belt are made of Archaean terranes and contain crust at least 3.2 and are underlain by a thick () layer of buoyant mantle that is producing garnets and diamonds. During the Palaeoproterozoic the northwest margin of the Archaean core grew