Geological History of South Africa
First of all, let’s look at the bigger picture: the Geology of South Africa
Diverse range of rocks form the end tip of the African continent – South Africa.
Large areas of the nation is underlain with Precambrian rocks (Barberton and Murchison Belts), the Limpopo mobile belt, and the Witwatersrand Supergroup. These are all formed during the Archean age.
Two thirds of the South African land is of the mesoproterozoic age. Meaning that the sediments and granite rocks that cover two thirds of the nation’s land is of the Paleozoic to Mesocoic Karoo Supergroup of continental clastic sediments and volcanics.
Now lets look at the history of how these rocks were formed.
About 3,500 – 2,500 Ma, during the Archean age, basements rocks that consist of large masses of granite intruded into the volcanic and sedimentary greenstone belts. This formed the oldest rocks of South Africa. These granite-greenstone basement rocks were then surrounded by younger rocks. Uplifted granite-greenstone terranes of South African has resulted into the Barberton mountain ranges as well.
As you can see in the map below, about two thirds of the nation is formed of sedimentary and volcanic rocks of the Karoo Supergroup. This was formed during the time period of about 300 to 140 Ma ago. However, Cape Town lies not on this majority area but under the Proterozoic subgroups of granite, limestones of the Cape Granite quite and the Malmesbury group.
Diverse range of rocks form the end tip of the African continent – South Africa.
Large areas of the nation is underlain with Precambrian rocks (Barberton and Murchison Belts), the Limpopo mobile belt, and the Witwatersrand Supergroup. These are all formed during the Archean age.
Two thirds of the South African land is of the mesoproterozoic age. Meaning that the sediments and granite rocks that cover two thirds of the nation’s land is of the Paleozoic to Mesocoic Karoo Supergroup of continental clastic sediments and volcanics.
Now lets look at the history of how these rocks were formed.
About 3,500 – 2,500 Ma, during the Archean age, basements rocks that consist of large masses of granite intruded into the volcanic and sedimentary greenstone belts. This formed the oldest rocks of South Africa. These granite-greenstone basement rocks were then surrounded by younger rocks. Uplifted granite-greenstone terranes of South African has resulted into the Barberton mountain ranges as well.
As you can see in the map below, about two thirds of the nation is formed of sedimentary and volcanic rocks of the Karoo Supergroup. This was formed during the time period of about 300 to 140 Ma ago. However, Cape Town lies not on this majority area but under the Proterozoic subgroups of granite, limestones of the Cape Granite quite and the Malmesbury group.
Image: Schluter, T. (2006). Geological Atlas of Africa. Springer Berlin Heidelberg.