Bedrock

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For other uses, see Bedrock (disambiguation).
"Subsurface" redirects here. For other uses, see Subsurface (disambiguation).
Soil with broken rock fragments overlying bedrock, Sandside Bay, Caithness.

In stratigraphy, bedrock is consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil. The top of the bedrock is known as rockhead and identifying this, via excavations, drilling or geophysical methods, is an important task in most civil engineering projects. Superficial deposits (also known as drift) can be extremely thick, such that the bedrock lies hundreds of meters below the surface.[1]

Bedrock may also experience subsurface weathering at its upper boundary, forming saprolite.

A solid geologic map of an area will usually show the distribution of differing rock types; i.e., rock that would be exposed at the surface if all soil or other superficial deposits were removed.[2]

soil horizon

Soil scientists use the capital letters O, A, B, C, and E to identify the master soil horizons, and lowercase letters for distinctions of these horizons. Most soils have three major horizons—the surface horizon (A), the subsoil (B), and the substratum (C). Some soils have an organic horizon (O) on the surface, but this horizon can also be buried. The master horizon, E, is used for subsurface horizons that have a significant loss of minerals (eluviation). Hard bedrock, which is not soil, uses the letter R.

References[edit]

External links[edit]

  • Media related to Bedrock at Wikimedia Commons