| Continent | Africa |
|---|---|
| Region | Eswatini,South Africa |
| Coordinates | 25°09′28″S26°44′11″E / 25.1577°S 26.7364°E /-25.1577; 26.7364 |
| Borders | Mozambique,Botswana,Zimbabwe |
TheTransvaal Basin is one of threebasins of theTransvaal Supergroup on theKaapvaal craton. The evolution of this 2.65–2.05GaNeoarchaean–Palaeoproterozoic basin is thought to have been derived largely frommagmatism,palaeoclimate andeustasy, whileplate tectonics played an intermittent role. The supergroup is made up of basal ‘protobasinal’ rocks, upon which followed theBlack Reef Formation,Chuniespoort Group and the uppermostPretoria Group.[1]
The Transvaal Supergroup displays threeunconformity-bounded sequences that surface in twogeographically distinct areas – the Transvaal Basin, which circumscribes theBushveld Igneous Complex, and theGriqualand West basin, lying betweenKimberley andSishen at the western Kaapvaal craton rim, extending into southernBotswana beneath theKalahari Sands as the Kanye Basin. The two basins areseparated by the broad Vryburg Arch.[2]
Between approximately 2.640 and 2.516 Ga, two successivestromatoliticcarbonate platforms developed in the basin of the Kaapvaal craton. Oldest was the Schmidtsdrif Subgroup, deposited in the southwestern part of the basin, showing stromatolitic carbonates,siliciclastic sediments and smalllava flows. This was followed by the Nauga formationcarbonates deposited onperitidal flats in the southwest, which were inundated during amarine transgression of the Transvaal Supergroup continental sea, at some 2.550 Ga. This resulted in a carbonate platform in the Transvaal and Griqualand West Basins, lastingfor 30–50 Ma.Shales were deposited during this period over the Nauga Formation carbonates. Following this a subsidence led to immersion of the stromatolitic platform and to sediments of iron-richbanded iron formations being laid down over the entire basin.[3]