Karoo Karoo The Karoo ( ; from a Khoikhoi word, possibly "garo" "desert") is a semi desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its extent is also not precisely defined. The Karoo is partly defined by its topography, geology and climate, and above all, its low rainfall, arid air, cloudless skies, and extremes of heat and cold. The Karoo also hosted a well-preserved ecosystem hundreds of million years ago which is now represented by many fossils. The Karoo formed an almost impenetrable barrier to the interior from Cape Town, and the
Karoo Group (i.e. the oldest layer of the Cape Supergroup). The valley floor is covered, in the main, by the next (younger) layer of the Supergroup, namely the much softer Bokkeveld shales. The dolerite of the Great Karoo did not penetrate these rocks, so Karoo Koppies are not seen in the Little Karoo. The Little Karoo contains two other geological features that give the landscape a special character. During the erosion of the African interior following the bulging of the continent during the massive lava outpourings that ended the Karoo sedimentation 180 million years ago, some of the eroded material was