In Earth science, a pothole is a smooth, bowl-shaped or cylindrical hollow, generally deeper than wide, found carved into the rocky bed of a watercourse. Other names used for riverine potholes are pot, (stream) kettle,

giant's kettle A giant's kettle, also known as either a giant's cauldron, moulin pothole, or glacial pothole, is a typically large and cylindrical pothole drilled in solid rock underlying a glacier either by water descending down a deep moulin or by gravel r ...

, evorsion, hollow, rock mill, churn hole, eddy mill, and kolk.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds., 2011. ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 800 pp. Although somewhat related to a pothole in origin, a

plunge pool A plunge pool (or plunge basin or waterfall lake) is a deep depression in a stream bed at the base of a waterfall or shut-in. It is created by the erosional forces of cascading water on the rocks at formation's base where the water impacts.Mars ...

(or plunge basin or waterfall lake) is the deep depression in a stream bed at the base of a

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in severa ...

. It is created by the

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

al forces of

turbulence In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...

generated by water falling on rocks at a waterfall's base where the water impacts.Marshak, Stephen, 2009. ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. Potholes are also sometimes referred to as swirlholes. This word was created to avoid confusion with an English term for a vertical or steeply inclined karstic shaft in

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

. However, given widespread usage of this term for a type of fluvial sculpted bedrock landform, ''pothole'' is preferred in usage to ''swirlhole''.Richardson, K. and Carling, P., 2005. ''A typology of sculpted forms in open bedrock channels.'' ''Special Paper'' 392. Boulder, Colorado: Geological Society of America. 108 pp. ThePotThatWashesItself

The term ''pothole'' is also used to refer to other types of depressions and basins that differ in origin. For example, some authorsChan, M.A., Moser, K., Davis, J.M., Southam, G., Hughes, K. and Graham, T., 2005. ''Desert potholes: ephemeral aquatic microsystems.'' ''Aquatic Geochemistry'', 11(3), pp. 279-302.Hughes, Kebbi A., 2012
''Bacterial Communities and their Influence on the Formation and Development of Potholes in Sandstone Surfaces of the Semi-Arid Colorado Plateau''
University of Western Ontario - Electronic Thesis and Dissertation Repository. Paper 543. refer to '' panholes'' found in the Colorado Plateau also as ''potholes''. Other terms used for panholes are ''gnamma'' (Australia), ''opferkessel'' (German, roughly “sacrificial basin”), ''armchair hollows'', ''weathering pans'' (or ''pits'') and ''solution pans'' or ''solution pits''.Twidale, C.R., and Bourne, J.A., 2018
''Rock basins (gnammas) revisited.''
Géomorphologie: Relief, Processus, Environnement, Articles sous presse, Varia, mis en ligne le 08 janvier 2018, consulté le 01 juillet 2018. In another case, the term ''pothole'' is used to refer to a shallow depression, generally less than in area that occurs between dunes or on subdued morainic relief on a

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

, as in

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

and

the Dakotas The Dakotas is a collective term for the U.S. states of North Dakota and South Dakota. It has been used historically to describe the Dakota Territory, and is still used for the collective heritage, culture, geography, fauna, sociology, econo ...

, and often contains an intermittent pond or marsh that serves as a nesting place for waterfowl.

Origin

The consensus of geomorphologists and sedimentologists is that fluvial potholes are created by the grinding action of either a stone or stones or coarse

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

(

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...

, gravel, pebbles, boulders), whirled around and kept in motion by eddies within and force of the stream current in a given spot. Being a spectacular feature of bedrock river channels, they have been and still are studied extensively and considered as a key factor in bedrock channel development and morphology and important factor in the incision of bedrock channels.Das, B.C., 2018. ''Development of Streambed Potholes and the Role of Grinding Stones.'' ''Journal of Environmental Geography.'' 11 (1–2), 9–16.Whipple, K.X., Hancock, G.S., and Anderson, R.S., 2000. ''River Incision Into Bedrock: Mechanics And Relative Efficacy Of Plucking, Abrasion And Cavitation.'' ''Geological Society Of America Bulletin.'' 112, 490–503.

References

{{reflist Landforms Depressions (geology)