Bedrock is the solid rock that underlies looser surface material.[1] An exposed portion of bedrock is often called an
outcrop.[2] The various kinds of broken and weathered rock material, such as
soil and
subsoil, that may overlie the bedrock are known as
regolith.[3][4]
Engineering geology
The surface of the bedrock beneath the soil cover (regolith) is also known as rockhead in
engineering geology,[5][6] and its identification by digging, drilling or
geophysical methods is an important task in most
civil engineering projects. Superficial
deposits can be very thick, such that the bedrock lies hundreds of meters below the surface.[7]
Weathering of bedrock
Exposed bedrock experiences
weathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to
erosion. Bedrock may also experience subsurface weathering at its upper boundary, forming
saprolite.[8]
Geologic map
A
geologic map of an area will usually show the distribution of differing bedrock types, rock that would be exposed at the surface if all
soil 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, as
alluvium).[9]
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.