Weathering occurs effectively where water, air and life are in contact with rock. Such contact occurs over the surface of rocks but also along fractures. Fractures may give water, air and life deep access to the interior of rocks so weathering can also take place there. Here, groundwater that seeped into the rock along fractures has redistributed iron oxides within the adjacent rock and made that part of the rock more resistant to erosion.

© 2001
Photo by David J. Leveson