Figure 18.19

GEO-GRAPHIC: The making of a bornhardt. (A) Bornhardts are formed by exhumation of an igneous intrusion through erosion. Once the igneous intrusion is exposed, erosion begins to wear it down, but at a slower rate than the surrounding weaker sediments. (B) Spitzkoppe, in Namibia, is a bornhardt composed of granite.

(David du Plessis/Gallo Images ROOTS Collection/Getty Images)