The rocks overlying the Natal Group
is a thick unit of tillite that was deposited in a glacial
environment by retreating ice sheets about 300 million years ago.
covering Gondwana 300 million years ago
At this time
South Africa was part of the supercontinent Gondwana, which was situated
near the south pole and covered with ice. Rocks imbedded in the slowly
moving ice sheets scoured and polished the underlying older rocks giving
rise to glacial pavements. Striation directions indicate that ice flow was
from north to south - valuable information when it comes to reconstructing
The picture shows a
striation on the rock surface caused by the movement of
ice and boulders about 300 million years ago.
Locality:University of KwaZulu-Natal,
Move your mouse onto the picture to
see the movement direction.
Tillite is mostly a very
fine-grained, blue-grey rock comprised of clay matrix
with inclusions (or clasts) of many other fragments
picked up by glaciers during their travels.
example of Dwyka tillite
The tillite in KZN often weathers to
a characteristic yellowish colour. In the Durban area,
cliffs near the mouth of the Umgeni River, and quarries
in the Westville area offer the best exposures of