Science and Technology Education Centre
(STEC@UKZN)

Natal Group

first sediments of a new continent

Natal group map

The first sedimentary sequence deposited on the new basement was the Cambrian to Ordovician Natal Group (490 million years ago).

Structures preserved in these sandstones indicate that the sediments were transported and deposited by rivers that drained highlands to the northeast. Close to their source, in northern KZN, deep valleys were infilled with thick accumulations of boulders and pebbles.

 

Natal Group sandstone, Kranskloof

Further south the sediment is finer grained and forms resistant sandstone cliffs. These give rise to the table top topography seen in the Valley of a Thousand Hills and Oribi Gorge near Port Shepstone.

Contact Natal Metamorphic and Natal group
Contact between the Natal Metamorphic Province granite and the Natal group sandstone, Mgeni River, Valley of the Thousand Hills
Oribi Gorge
Natal Group sandstone, Oribi Gorge

Source: https://en.wikipedia.org/wiki/Oribi_Gorge#/media/File:Oribi_gorge.jpg

Sandstone (sedimentary)

Rivers

Typically pinkish-coloured, these sandstones are medium-grained (sand grains are visible to the naked eye) and may be seen as table-top mountains with cliffs having very clear layers known as bedding. The sand was deposited in a river environment and ripple marks may be seen in large rock outcrops.