Karoo (crater) Karoo (crater) Karoo is an impact crater on the Asteroid 253 Mathilde, named for the Great Karoo Basin, a coal basin in South Africa. It is 33.4 kilometers in diameter and was the most prominent crater seen during NEAR Shoemaker's Flyby of the Asteroid. The critical crater diameter is the scale at which cratering “goes global” and results in a solitary distinct crater. All smaller craters—however large D might be—are local events. Mathilde is thus a particularly interesting case, since it is the largest asteroid imaged at sufficient resolution to show that its topography is clearly exogenic, governed by impacts.
Karoo plain with Mississippi-like rivers depositing mud from an immense range of mountains to the south. Ancient reptiles and amphibians prospered in the wet forests, and their remains have made the Karoo famous amongst palaeontologists. The first of these Karoo fossils was discovered in 1838 by Scots-born Andrew Geddes Bain at a road cutting near Fort Beaufort. He sent his specimens to the British Museum, where fellow Scotsman Robert Broom recognised the Karoo fossils' mammal-like characteristics in 1897. After the Beaufort period, Southern Africa (still part of Gondwana) became an arid sand desert with only ephemeral rivers and pans. These sands