Geological History of Cape Town
The Cape Peninsula in which Cape Town is located is comprised of three main rock formations: The Malmesbury Group, the Cape Graniet, and the Table Mountain Group. Let’s look at the Geological History of Cape T years agwn through these three rock formations.
Through a simplified diagram, this what the geological map of the Cape Peninsula looks like:
Through a simplified diagram, this what the geological map of the Cape Peninsula looks like:
Image:
Cape town geology. (n.d.). Retrieved March 9, 2015, from University of Cape Town: Department of Geological Sciences website: http://www.geology.uct.ac.za/cape/town/geology
The oldest rock formation is the one located in the most bottom – the Malmesbury Group. It was formed about 600 Ma, and mostly consists of dark grey mudstones and light colored sandstones. This stone is very vulnerable to weathering therefore is usually covered by soil and sand and is not exposed.
Secondly, the Cape Granite is the second oldest, formed around 540 Ma. It is formed by the upwelling of magma that intruded the Malmesbury Group. It is much harder and more coarse grained, consisting of large white feldspar crystals, and flakes of glassy quartz.
Last but not least, the youngest rock formation is the Table Mountain Group which was formed around 520 Ma. Most of the Western Cape’s mountain ranges are formed by the Table Mountain Sandstone, including the infamous Table Mountain itself. This sedimentary rock is extremely strong and resistant to weathering.
Focusing on the Table Mountain group, it was formed through 3 different formations:
1. The Graafwater Formation
2. The Peninsula Formation
3. The Palhuis Formation
Cape town geology. (n.d.). Retrieved March 9, 2015, from University of Cape Town: Department of Geological Sciences website: http://www.geology.uct.ac.za/cape/town/geology
The oldest rock formation is the one located in the most bottom – the Malmesbury Group. It was formed about 600 Ma, and mostly consists of dark grey mudstones and light colored sandstones. This stone is very vulnerable to weathering therefore is usually covered by soil and sand and is not exposed.
Secondly, the Cape Granite is the second oldest, formed around 540 Ma. It is formed by the upwelling of magma that intruded the Malmesbury Group. It is much harder and more coarse grained, consisting of large white feldspar crystals, and flakes of glassy quartz.
Last but not least, the youngest rock formation is the Table Mountain Group which was formed around 520 Ma. Most of the Western Cape’s mountain ranges are formed by the Table Mountain Sandstone, including the infamous Table Mountain itself. This sedimentary rock is extremely strong and resistant to weathering.
Focusing on the Table Mountain group, it was formed through 3 different formations:
1. The Graafwater Formation
2. The Peninsula Formation
3. The Palhuis Formation