Widespread Mesozoic stratigraphic unit in southern Africa
Stratigraphy of the Karoo Supergroup in the Karoo Basin
Period
Group
Formation west of 24°E
Formation east of 24°E
Assemblage Zone
Jurassic
Drakensberg
Hiatus
Drakensberg
Stormberg
Clarens
Triassic
Elliot
Molteno
Beaufort
Burgersdorp
Cynognathus
Katberg
Lystrosaurus
Balfour
Permian
Dicynodon
Teekloof
Cistecephalus
Middleton
Tropidostoma
Pristerognathus
Abrahams-Kraal
Abrahams-Kraal
Tapinocephalus
Eodicynodon
Ecca
Waterford
Waterford
Tierberg / Fort Brown
Fort Brown
Laingsburg / Ripon
Ripon
Collingham
Collingham
Whitehill
Whitehill
Prince Albert
Prince Albert
Carboniferous
Dwyka
Elandsvlei
Elandsvlei
References: Rubidge (2005),[1] Selden and Nudds (2011).[2]
The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a period of about 120 million years.[3]
In southern Africa, rocks of the Karoo Supergroup cover almost two thirds of the present land surface, including all of Lesotho, almost the whole of Free State, and large parts of the Eastern Cape, Northern Cape, Mpumalanga and KwaZulu-Natal Provinces of South Africa. Karoo supergroup outcrops are also found in Namibia, Eswatini, Zambia, Zimbabwe and Malawi, as well as on other continents that were part of Gondwana. The basins in which it was deposited formed during the formation and breakup of Pangea.[4][5] The type area of the Karoo Supergroup is the Great Karoo in South Africa, where the most extensive outcrops of the sequence are exposed.[3][6] Its strata, which consist mostly of shales and sandstones,[7] record an almost continuous sequence of marine glacial to terrestrial deposition from the Late Carboniferous to the Early Jurassic. These accumulated in a retroarc foreland basin called the "main Karoo" Basin.[4] This basin was formed by the subduction and orogenesis along the southern border of what eventually became Southern Africa, in southern Gondwana.[4] Its sediments attain a maximum cumulative thickness of 12 km, with the overlying basaltic lavas (the Drakensberg Group) at least 1.4 km thick.[8]
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. Their biostratigraphy has been used as the international standard for global correlation of Permian to Jurassic nonmarine strata.[9]
A timeline of the Earth's geological history, with an emphasis on events in Southern Africa. The green block labeled K indicates when the Karoo Supergroup was deposited, in relation to the Cape supergroup, C, immediately before it. The W indicates when the Witwatersrand supergroup was laid down, very much further in the past. The graph also indicates the period during which banded ironstone formations were formed on Earth, indicative of an oxygen-free atmosphere. The Earth's crust was wholly or partially molten during the Hadean Eon; the oldest rocks on Earth are therefore less than 4000 million years old. One of the first microcontinents to form was the Kaapvaal Craton, which forms the foundation of the north-eastern part of the country. The assembly and break-up of Gondwana are, in terms of the Earth's and South Africa's geological history, relatively recent events.
^Rubidge, B.S. (2005). "Re-uniting lost continents – Fossil reptiles from the ancient Karoo and their wanderlust". South African Journal of Geology. 108 (1): 135–172. doi:10.2113/108.1.135.
^Selden, P.; and Nudds, J. (2011). "Karoo". Evolution of Fossil Ecosystems (2 ed.). Manson Publishing. pp. 104–122. ISBN 9781840761603.
^ abSchlüter, Thomas (2008). Geological Atlas of Africa: With Notes on Stratigraphy, Tectonics, Economic Geology, Geohazards and Geosites of Each Country (2nd ed.). Springer. pp. 26–28. ISBN 9783540763734.
^ abcCatuneanu, O; Wopfner, H; Eriksson, P; Cairncross, B; Rubidge, B; Smith, R; Hancox, P (2005). "The Karoo basins of south-central Africa" (PDF). Journal of African Earth Sciences. 43 (1–3): 211. Bibcode:2005JAfES..43..211C. doi:10.1016/j.jafrearsci.2005.07.007.
^McCarthy, T., Rubridge, B. (2005). The Story of Earth and Life. pp. 161, 187–241. Struik Publishers, Cape Town
^Geological map of South Africa, Lesotho and Swaziland (1970). Council for Geoscience, Geological Survey of South Africa.
^Hamilton, G.N.G. and Finlay, J.G. (1928). Outline of Geology for South African Students, Central News Agency Ltd., Johannesburg.
^Adelmann, D. and Kerstin Fiedler, (1996). "Sedimentary development of the Upper Ecca and Lower Beaufort Groups (Karoo Supergroup) in the Laingsburg subbasin (SW Karoo Basin, Cape Province/South Africa)" Archived 2005-09-03 at the Wayback Machine, Schriftenreihe der Deutschen Geologischen Gesellschaft, 1: 88–89, Bonn.
^Hancox, P. J. and Bruce S. Rubidge (1997). The role of fossils in interpreting the development of the Karoo basin, Palaeontologica Africana, 33: 41–54.
The KarooSupergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units...
succulent Karoo and the Nama Karoo, although both, like the geological KarooSupergroup, are more extensive than the geographical or historical Karoo described...
system, into which the KarooSupergroup was deposited. Eventually much of the Cape Supergroup became buried under these Karoo deposits, only to re-emerge...
members of the Supergroup are exposed in the north, where the entire Cape Supergroup dives beneath the Karoo rocks. Drilling in the Karoo has established...
Drakensberg escarpment is composed of Ecca shales, which belong to the KarooSupergroup, and they are 300 million years old. The portion of the Drakensberg...
dome (where it is not covered by much younger rocks belonging to the KarooSupergroup) which is an exposed part of the Kaapvaal craton, one of the oldest...
sediments to form the Katanga Supergroup and rift-related KarooSupergroup. Basalt eruptions blanketed the KarooSupergroup in the Mesozoic and Zambia shifted...
sills are preserved throughout the Karoo Basin, and have served as a weathering barrier for much of the KarooSupergroup rocks. The Drakensberg Group comprises...
layers of the Witwatersrand Supergroup of rocks, on the southern side of the Witwatersrand plateau. The Witwatersrand Supergroup strata which reach the surface...
The Lower Karoo Group is a sequence of late Carboniferous and Permian sandstone sedimentary rocks of the KarooSupergroup, found in Botswana, Zambia,...
South Africa are to be found in the Ecca deposits, a stratum of the KarooSupergroup, dating from the Permian period, between 280 and 250 Ma. The Ecca Group...
south, buried the folded Cape Supergroup rocks, and the plains beyond (to the north) to ultimately form the KarooSupergroup, a sequence of sediments that...
the KarooSupergroup in South Africa. It is the uppermost geological group representing the final phase of preserved sedimentation of the Karoo Basin...
genus forms a Cynognathus Assemblage Zone in the Beaufort Group of the KarooSupergroup. Seeley in 1894/1895 placed Cynognathus in a separate family Cynognathidae...
terrestrial tetrapod ecological representation in the Beaufort Group (KarooSupergroup) of South Africa". Lethaia. 43: 45–59. doi:10.1111/j.1502-3931.2009...
Group, which is part of the fossiliferous and geologically important KarooSupergroup. The Cynognathus Assemblage Zone is the youngest of the eight biozones...
downwarping of the crust during the Paleozoic and Mesozoic, as the massive KarooSupergroup deposited. Within the past 100 million years, Tanzania has experienced...
compose the KarooSupergroup. It is the lowermost geological group and heralds the commencement of sedimentation of the KarooSupergroup. Based on stratigraphic...
Wuchiapingian) aged sediments of the Tropidostoma Assemblage Zone, in the KarooSupergroup of South Africa, belonging to the basal family Charassognathidae. Fossils...
a fossiliferous and geologically important geological Group of the KarooSupergroup in South Africa. This biozone has outcrops in the south central Eastern...
been found in the Late Permian to Early Triassic of the South African KarooSupergroup. It was a large carnivorous therapsid, reaching 1.5 m (4.9 ft) in total...
that forms part of the greater KarooSupergroup. It represents the first fully terrestrial geological deposits of the Karoo Basin. Outcrops of the Abrahamskraal...
during the Permian, Pangaea, gorgonopsians have only been found in the KarooSupergroup (primarily in South Africa, but also in Tanzania, Zambia, and Malawi)...
The Beaufort Group is the third of the main subdivisions of the KarooSupergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper...
majorly fossiliferous and geologically important geological group of the KarooSupergroup in South Africa. This biozone has outcrops located in the Teekloof...
Middle Permian (Capitanian stage) and fossils can be found in the KarooSupergroup of South Africa. Eunotosaurus resided in the swamps of southern Africa...
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