Table Mountain (1084.6m) was exposed by erosion over millions of years. Since Gondwana split up 130 million years ago, the Cape Flats has seen great changes, from high sea levels in the last few million years (which joined Table Bay to False Bay), to low sea levels as recently as 20 000 years ago (the Last Ice Age) when Robben Island, Table Bay and False Bay were all part of the mainland.
For much of the Peninsula the upper half is mainly Sandstone of the Table Mountain Group, originally deposited by rivers up to 520 million years ago, overlying older Granite, which is 540 million years old. The oldest rocks are on Signal Hill, north of Lion's Head, which consist of Malmesbury Group's marine siltstones (560 million years old). Zircon crystals were used to date these rocks that once formed part of the ancient supercontinent Gondwana. The bedrock of Wynberg Hill and Constantia Valley is granite, which weathers to a soil very suitable for vines. Chapman's Peak Drive runs down the contact (nonconformity) between the older Cape Granite and the younger Table Mountain Sandstone.
|© Gerald Hoberman|