The Karoo Supergroup is the largest stratigraphic unit in Southern Africa, covering almost two thirds of the present land surface, including central Cape Province, almost all of Orange Free State, western Natal, much of south-east Transvaal, Zambia, Zimbabwe and Malawi.
Its strata, mostly shales and sandstones (Hamilton & Finlay 1928), record an almost continuous sequence of marine glacial to terrestrial deposition from the Late Carboniferous to the Early Jurassic, a period of about a hundred million years. These accumulated in a retroarc foreland basin called the Karoo Basin. Its sediments attain a maximum cumulative thickness of 12 km, with the overlying basaltic lavas (the Drakensberg Group) at least 1.4 km thick.(Adelmann and Fiedler 1996).
Fossils include plants (both macro-fossils and pollen), rare insects and fish, common and diverse tetrapods (mostly therapsid reptiles, temnospondyl amphibians, and in the upper strata dinosaurs), and ichnofossils. Dinosaurs found in this supergroup include the prosauropod Massospondylus and the ornithopod Heterodontosaurus. Two formations that yield the most dinosaur fossils are the Elliott Formation (Jurassic) and the Bushveld Sandstone Formation, which was the location of the Massospondylus discovery. Their biostratigraphy has been used as the international standard for global correlation of Permian to Jurassic nonmarine strata (Hancox & Rubidge, 1997).
South African paleontologist Robert Broom unearthed some of the first known therapsids from this supergroup, and further excavations led to the discoveries of Lystrosaurus, Cynognathus, and Moschops. Of interesting note are some of the geologic zones that have been named after discoveries, such as the Cynognathus Zone, Lystrosaurus Zone, and other.
The Karoo Supergroup is divided into the following strata (from oldest to youngest):
- Dwyka Group (glacial marine)
- Ecca Group
- Beaufort Group (terrestrial)
- Stormberg Group (including basalts)
- Adelmann, D. and Fiedler, K., (1996), Sedimentary development of the Upper Ecca and Lower Beaufort Groups (Karoo Supergroup) in the Laingsburg subbasin (SW Karoo Basin, Cape Province/South Africa), Schriftenreihe der Deutschen Geologischen Gesellschaft, 1: 88-89, Bonn.
- Hamilton, G.N.G. and Finlay, J.G. (1928), Outline of Geology for South African Students, Central News Agency Ltd, Johannesburg
- Hancox, P.J. & Rubidge, B.S. (1997), The role of fossils in interpreting the development of the Karoo basin. Palaeontol. Afr. 33: 41-54.
- Ponomarenko A.G. & Mostovski M.B. 2005. New beetles (Insecta: Coleoptera) from the Late Permian of South Africa. African Invertebrates 46: 253-260.
- Sukatsheva I.D., Beattie R. & Mostovski M.B. 2007. Permomerope natalensis sp. n. from the Lopingian of South Africa, and a redescription of the type species of Permomerope (Insecta: Trichoptera). African Invertebrates 48 (2): 245-251.