STRATIGRAPHIC CONTINUITY IN PERMIAN KAROO BASINS, SOUTH AFRICA, NAMIBIA, AND BOTSWANA

Carboniferous-Permian sedimentary rocks of South Africa, Namibia, and Botswana preserve glaciomarine and marine sedimentary successions of the Dwyka and Ecca groups. In western South Africa, the Ecca Group consists of deep marine shales (Prince Albert and Whitehill formations) overlain by progradational sandstones (Skoorsteenberg and Kookfontein formations) from a northeastward prograding shelf-slope system. To the north, in Karasburg, southern Namibia, the Prince Albert and Whitehill shales are lithostratigraphically similar to the south, but the progradational sequence is overlain by the poorly known Aussenkehr Sandstone Formation. In the Aranos Basin of eastern Namibia and Kalahari Karoo of Botswana, south and southwestward prograding deltas and wave-dominated shorelines occur.

The Karasburg Karoo is commonly interpreted as a distal equivalent of the prograding depositional systems of the Aranos Basin. However, inliers of Karoo sediment between the main Karoo Basin and southern Namibia suggest that these two basins were also continuous during the Permian. Crustal subsidence during the Ecca deposition therefore extended across a wide region encompassing western South Africa, Namibia, and southern Botswana.