During the Cenozoic sea-level began to fall from the high levels experienced during the Cretaceous. A series of large coast-parallel dune complexes developed along most of the KwaZulu-Natal coastline. In Durban these now form the Berea and Bluff Ridges (below). In most areas deep weathering of old dunes has produced a dark red coloured sand called the Berea Red Sand.


The Bluff

In more recent times, fluctuations in sea-level have continued to shape the KwaZulu-Natal coastline. Recent coastal dunes contain economic concentrations of minerals such as ilmenite, rutile and zircon, which are mined near Richards Bay.

The ilmenite and rutile is smelted to produce titanium metal and white pigments (mostly for paint). The zircon is used for glazing on tiles and pottery, and as a metal alloy.


KZN shoreline 18 000 years ago

During the last glacial period, approximately 18 000 years ago, the Earth was much colder and sea level was more than 100 metres below present. The coastline at that time would have been far out to sea and many of the larger rivers cut deep valleys along the coast. As the Earth warmed and sea-level rose, these valleys were infilled with unconsolidated estuarine muds and shelly sands. It is for this reason that many bridges along the coast require deep foundations to reach solid bedrock.



Sea level fluctuation (after Dr. P. Ramsay)

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