Ancient Baviaanskloof Mountains
The Baviaanskloof as we know it today was profoundly shaped through a succession of geological events that were initiated about 140 million years ago, during the Cretaceous. The break-up of Gondwanaland into the continents that we know today occurred when faulting occurred roughly along the present-day coastlines of South Africa. A major tensional fault formed along what later became known as the Baviaanskloof. The 'modern' Baviaanskloof is about 20 million years old and was formed during the Tertiary by erosion as a result of repeated subsidence and upliftment events (Hattingh 2001).
Contrasting with the steep rugged gorges and mountain slopes are some remarkably flat plateau's at an altitude of 650-900m. These are part of what is known as the African Land Surface, an old "mature" land surface which is found over large parts of sub-Saharan Africa. The confluence of the Baviaanskloof with the Kouga River lies at less than 160 m above sea level, while the highest points in the area are Scholzberg (1626 m) in the Baviaanskloof mountains and Smutsberg (1758 m) in the Kouga mountains. The topography is dominated by steep slopes: only about 30% of the area has a slope of less than 30%. The most common slope angle in the valley ranges between 30 and 40%, but it reaches 60% in some areas (Illgner & Haigh 2003).
The parent material of the Baviaanskloof is dominated by sandstone and quartzites of the Table Mountain Group (TMG), intermixed with shale layers. The soils formed on the mountain slopes are shallow, due to the steepness. These soils are relatively nutrient-poor because the quartz (SiO2) from which the quartzite and sandstone are primarily derived provides nutrient poor base material. These soils are classified as Dundee type, because of the sandy, stratified alluvial characteristics ( Hatting 2011, Sommeijer 2010, Draaijer 2010, Jansen 2008, Boshof 2005).
The valleys are characterized by fault-fractured quartzite, Bokkeveld shale and Enon conglomerate, which weathers relatively easily. Enon Conglomerates are fairly prominent in the Baviaanskloof-Kouga fault, which runs east-west in the watershed (Draaijer 2010). The weathered conglomerate is characterized by red clay and rounded rocks. The red colour is caused by the iron ioxide in the sandy matrix. The rounded rocks belong to the Cape Supergroup formations.
Authors: Bart van Eck & Silvia Weel (2012)
Interesting formations in the Baviaanskloof:
Peninsula Sandstone - the oldest formation which usually dominates at higher altitudes and the peaks.
Cedarberg Shale - it separates the Peninsula from the Goudini formation with a 10-40m wide bar and is usually associated with lower lying necks and saddles.
Goudini Sandstone - is generally brown in colour and can often be recognised by the numerous shallow caves in the cliffs.
Skurweberg Sandstone - is associated with the Cockscomb and most of the higher peaks of the Baviaanskloof range.
Sardinia Bay - is mixed with phyllitic shales and small-pebble conglomerate. It can be seen at low altitudes at the eastern end of the Baviaanskloof range.
Baviaanskloof - is dark in colour and, along with the Sardinia Bay formation, is relatively uncommon.
A number of other formations are present but are insubordinate in the landscape. Noteworthy one include the Grahamstown Formation which can be found on the flat plateau surfaces and has been termed the African Land surface, and the Enon Conglomerate formation, a maroon formation which erodes into dramatic shapes, found at Kamerkloof.