Karoo an immense volume of rocks which was formed, geologically speaking, in a short period of time. Although almost the whole of the Great Karoo is situated on Karoo Supergroup rocks, the geological Karoo rocks extend over a very much larger area, both within South Africa and Lesotho, but also beyond its borders and onto other continents that formed part of Gondwana. The Karoo Supergroup was formed in vast inland basin starting 320 million years ago, at a time when the part of Gondwana which would eventually become Africa lay over the South Pole. Icebergs that had calved off the glaciers
Karoo which is Afrikaans for Little Karoo. The Great Karoo straddles the 30° S parallel on the west of the continent, in a similar position to other semidesert areas on earth, north and south of the equator. It is furthermore in the rainfall shadow of the Cape Fold Mountains along the western coastline. The western "Lower Karoo" (the Tankwa Karoo and Moordenaarskaroo) contain remnants of the Cape Fold Mountains (e.g. the Witteberg and Anysberg Mountains) which give it a moderate hilly appearance, but further east, the Lower Karoo becomes a monotonously flat plain. The "Upper Karoo" has been intruded by dolerite