Bedrock is the solid rock that underlies looser surface material.[1] An exposed portion of bedrock is often called anoutcrop.[2] The various kinds of broken and weathered rock material, such assoil andsubsoil, that may overlie the bedrock are known asregolith.[3][4]
The surface of the bedrock beneath the soil cover (regolith) is also known asrockhead inengineering geology,[5][6] and its identification by digging, drilling orgeophysical methods is an important task in mostcivil engineering projects. Superficialdeposits can be very thick, such that the bedrock lies hundreds of meters below the surface.[7]
Exposed bedrock experiencesweathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible toerosion. Bedrock may also experience subsurface weathering at its upper boundary, formingsaprolite.[8]Rock fragments can disconnect from the underlying bedrock, where they are found within a weathering orsoil profile asfloaters.[9]
Ageological map of an area will usually show the distribution of differing bedrock types, rock that would be exposed at the surface if allsoil or other superficial deposits were removed. Where superficial deposits are so thick that the underlying bedrock cannot be reliably mapped, the superficial deposits will be mapped instead (for example, asalluvium).[10]
Harris, Clay (2013). "Bedrock". In Lerner, K. Lee; Lerner, Brenda Wilmoth (eds.).The Gale Encyclopedia of Science. Vol. 1 (5th ed.). Farmington Hills, MI: Cengage Gale. pp. 515–516.
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