Spheroidal weathering

Spheroidal or woolsack weathering in granite on Haytor, Dartmoor, England
Spheroidal weathering in granite, Estaca de Bares, A Coruña, Galicia, Spain
Woolsack weathering in sandstone at the Externsteine rocks, Teutoburg Forest, Germany
Corestones near Musina, South Africa that were created by spherodial weathering and exposed by the removal of surrounding saprolite by erosion.
Spheroidal weathering of a dolerite dyke, Pilbara, Western Australia

Spheroidal weathering is a form of chemical weathering that affects jointed bedrock and results in the formation of concentric or spherical layers of highly decayed rock within weathered bedrock that is known as saprolite. When saprolite is exposed by physical erosion, these concentric layers peel (spall) off as concentric shells much like the layers of a peeled onion. Within saprolite, spheroidal weathering often creates rounded boulders, known as corestones or woolsack, of relatively unweathered rock. Spheroidal weathering is also called onion skin weathering, concentric weathering, spherical weathering, or woolsack weathering.[1][2][3][4]

  1. ^ Fairbridge, RW (1968) Spheroidal Weathering. in RW Fairbridge, ed., pp. 1041–1044, The Encyclopedia of Geomorphology, Encyclopedia of Earth Sciences, vol. III. Reinhold Book Corporation, New York, New York.
  2. ^ Ollier, C.D. (1971). Causes of spheroidal weathering. Earth-Science Reviews 7:127–141.
  3. ^ Neuendorf, KKE, JP Mehl Jr., and JA Jackson, eds. (2005) Glossary of Geology (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. ISBN 0-922152-76-4
  4. ^ Kolawole, F.; Anifowose, A. Y. B. (2011-01-01). "Talus Caves: Geotourist Attractions Formed by Spheroidal and Exfoliation Weathering on Akure-Ado Inselbergs, Southwestern Nigeria". Ethiopian Journal of Environmental Studies and Management. 4 (3): 1–6. doi:10.4314/ejesm.v4i3.1. ISSN 1998-0507.