Geology

Geological and landscape assets

The whole of the area defined as the Karoo lies on the suite of rocks known as ‘The Karoo Supergroup’. At many places in the Karoo, different portions of this enormously thick succession of rocks are exposed, providing insights into the depositional environments at the time the rocks were laid down, between 280 and 180 million years ago.

The southern margin of the geographical Karoo, the Cape Fold Mountains, show spectacular examples of folding and thrusting by the titanic forces which created the Karoo basin and sea, particularly in the passes that cut through or ascend over the ranges.

Further to the north, the igneous intrusions that heralded the break-up of the supercontinent Gondwana often give rise to the flat-topped koppies of the Karoo, or to conspicuous dykes cutting across the older sedimentary layers, or they weather into ‘woolsack’ blocks or koppies of tumbled black rocks.

It is the desert varnish on the latter black boulder koppies that was engraved, pecked or scraped by the San to create the wonderful rock engravings of the Karoo.

Palaeontological assets

Embedded within the thick succession of sedimentary rocks are the fossilised remains of plants which grew at the edges of the Karoo sea and the animals which walked the extensive mudflats and floodplains of the meandering rivers which developed as the sea began to silt up. There is an almost unbroken record (except for a major extinction event) of the radiation and evolution of reptiles, which includes the transition from amphibian to reptile and from reptile to mammal, in the form of many thousands of fossils which occur throughout the Karoo.

A display of prehistory of the Karoo and of the fossil fish (250 million years of Atherstonia seeleyi found in the district) can be seen in the Victoria West Regional Museum.

Archaeological and Rock Art heritage

There is a scatter of artefacts dating from the Early Stone Age, Middle Stone Age and later Stone age all over the Karoo, but few stratified sites because people seldom lived for extensive periods at any one site – they were nomadic, leading and event-driven lives, following rains and seeking new growth and new pastures. One of the greatest heritage assets of the Karoo is its rock engraving sites where engraved, pecked or scraped images of eland, ostriches, zebra and other animals bear silent and unfathomable testimony to the former presence of the culturally extinct San.