Geological History

More than 600 million years ago rocks were forming in the Cape Town area. During the following hundred million years they went through trauma and reformation, which you can see the affects of today. You can see the layers of granite and sandstone that remain today and that for three main rock formations in the Cape Peninsula area. Those formations are:

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Figure 1: Crustal evolution [Available From:]

The Malmesbury Group

  • Late-Precambrian age
  • 540 million years old – oldest rock formation in the area
  • Dark grey mudstone and lighter sandstone
  • Originally deposited on an ancient continental slope by submarine slumping and currents
  • Metamorphosed by heat and pressure and folding
  • Foundation of many buildings



Figure 2: Malmesbury Group sediments on the eastern side of False Bay [Available From:]
Figure 3: Sea Point migmatite [Available From:]

Cape Granite

  • Batholith intruded into the Malmesbury Group 630 million years ago as magma
  • Hard and coarse-grained large white or pink feldspar crystals
  • Flakes of black mica and glassy grey/brown quartz
  • The foundation for most of the Table Mountain Chain
  • Exposed to erosion
  • Granite boulders are a result of weathering


Figure 4: Granite Boulders [Available From:]
Figure 5: Granite Boulders on Boulders Beach [Available From:]

Table Mountain Group

  • Eroded surface of granite basement in stream channels and tidal flats 450 million years ago
  • Weather-resistant sedimentary rocks
  • Approximately 2 km thick
  • Sand, silt, and mud deposits lithified by pressure and folding


Figure 6: Table Mountain sediments [Available From:]


Figure 7: Table Mountain sandstone [Available From:]


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