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. As the rock is weathered along fractures, the products of weathering may be removed, enlarging the fractures and enhancing the process. Here, groundwater that seeped into the rock along the fracture has redistributed iron oxides within the adjacent rock.

© 2001
Photo by David J. Leveson