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. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mathilde they are named after coal fields and basins of the world.
Sorry, there hasn't been a good map made for this world yet :(