Geology of the Cape Fold Belt – South Africa
International - Date: 21st - 27th August/2016
The Cape Fold Belt (CFB), in South Africa, is the easternmost continuation of the Argentinian Sierra de La Ventana Belt. They were formed as a result of a convergent tectonic process in the southern margin of the Supercontinent Gondwana (Gondwanide Orogen), forming a fold-thrust belt more than 2.000 km long during the Permian.
The CFB is subdivided into three tectonic domains: the western branch, 270 km long and N-S direction; the eastern branch with more than 600 km and E-W direction; and the Cape Syntaxis, the area between the two branches with a NE-SW structural grain and 100 km wide.
The CFB rocks overlays the Pan-African Saldanian Belt that was formed during the assembly of the Gondwana Supercontinent. These rocks are divided into two supergroups, Cape and Karoo. The Cape Supergroup (Cambrian-Carboniferous) makes up most of the sedimentary rocks in the CBF and it is subdivided into three units, the Table Mountain Group, the Bokkeveld Group and the Witteberg Group. The Karoo Supergroup (Carboniferous-Jurassic) begins with the Dwyka tillite, representing a glacial period when Gondwana was passing over the south pole. The overlying rocks are divided in two units, the Ecca Group and the Beaufort Group. The last group represents the first phase of fluvial deposition the Karoo Basin.
This field trip was a part of the 35th International Geological Congress in Cape Town. We left Cape Town on the 21 August of 2016 where the tour took place in historical mountain passes until Knysna, returning to Cape Town in the 27 August.