Cape Fold Belt - Orogeny

Orogeny

The mountains are not particularly ancient, despite their old-looking appearance. They are considered middle-aged in geologic terms. They were created during continental collision when Pangaea, the supercontinent formed from the late Carboniferous to Permian periods. Their stature is mostly due to their weather-resistant rocks of quartzitic sandstone, with the shale formations generally forming the valleys, capped by alluvial deposits, which are generally Quaternary in age.

The mountains were folded during this period and were still buried beneath the Earth's surface. Due to the extreme temperatures and lithic pressure at these depths, folding was not a brittle process, as the rocks retained a "plastic" constituency, making the Cape Fold Mountains spectacular in their exposed folded, faulted and twisted sedimentary strata. A number of parallel faults still runs roughly parallel with the coast, having formed during the Gondwanaland rifting when South America separated from Africa. Patagonia was to the west of Cape Town and the Falkland Islands were to the south during the Jurassic Period prior to separation. This faulting has caused the Table Mountain Sandstone to be exposed closer to and above sea level close to the coast, but gradually becoming deeper embedded in the overlying strata further inland, excluding areas where folding has caused anticlines to expose the rocks higher up (e.g. Swartberg Mountains north of the Oudtshoorn Fault.

The opening of Pangaea and subsequently Gondwanaland also aided in their "conservation" as a range, as the Cape Supergroup of rocks were capped by the deposition of the Karoo Sequence of sedimentary deposits, including the Dwyka Formation, which is compacted glacial till deposited during the late Permian southern ice age.