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
Tirari Desert and the Sturt Stony Desert runs aligned with the Birdsville track to the north east. The desert experiences harsh conditions with high temperatures and very low rainfall (mean annual rainfall is below ). The main vehicular access to the desert is via the unpaved Birdsville Track which runs northwards from Marree to Birdsville. The Mungerannie Hotel is the only location between the two towns that provides services. The Tirari Desert region has a number of large cattle stations which are stopping points on the Channel Country aviation mail run. Dulkaninna Station has been run by the same family for 110