The geology of the park provides very visual "textbook" examples of Southern Africa's geological history. The sandstone formations in the park form the upper part of the Karoo Supergroup. These formations were deposited during a period of aeolian deposition towards the end of the Triassic Period. At the time of deposition, the climate of the area the park covers was becoming progressively drier until arid desert conditions set in, resulting in a land of dunes and sandy desert, with occasional scattered oases. The deposition of the sandstones ended when lava flowed out over the desert 190 million years ago.