Open main menu
Soil with broken rock fragments overlying bedrock, Sandside Bay, Caithness

In geology, bedrock is the lithified rock that lies under a loose softer material called regolith within the surface of the crust of the Earth or other terrestrial planets.

Contents

Components of bedrockEdit

Bedrock essentially refers to the substructure composed of hard rock exposed or buried at the earths surface, an exposed portion of bedrock is often called an outcrop. Bedrock may have various chemical and mineralogical compositions and can be igneous, metamorphic or sedimentary in origin. The bedrock may be overlain by broken and weathered regolith which includes soil and the subsoil.[citation needed]

 
Soil profile with bedrock labeled R

Engineering geologyEdit

The surface of the bedrock beneath the soil cover (regolith) is also known as rockhead in engineering geology,[1][2] and its identification by digging, 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.[3]

Weathering of bedrockEdit

Bedrock when exposed or within the subsurface may experience weathering and erosion by external factors. Weathering may be physical or chemical and alters the structure of the rock and may cause it to erode and or alter over time based on the interactions between the mineralogy and its interactions. Bedrock may also experience subsurface weathering at its upper boundary, forming saprolite.[citation needed]

Geologic mapEdit

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.[4]

See alsoEdit

  • Geology – The study of the composition, structure, physical properties, and history of Earth's components, and the processes by which they are shaped.
  • Outcrop
  • Regolith – A layer of loose, heterogeneous superficial deposits covering solid rock
  • Soil – mixture of organic matter, minerals, gases, liquids, and organisms that together support life
  • Weathering – Breaking down of rocks, soil and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters

ReferencesEdit

  1. ^ Price, David George, Engineering Geology: Principles and Practice, Springer, 2009, p. 16 ISBN 978-3540292494
  2. ^ Gribble C. & McLean A. (2003). Geology for Civil Engineers. CRC Press. p. 113. ISBN 9780203362150.
  3. ^ "Swinford, E. Mac What the glaciers left behind – drift thickness map of Ohio, Ohio Department of Natural Resources, Division of Geological Survey, newsletter 2004, No.1" (PDF). Archived from the original (PDF) on 2012-10-02. Retrieved 2012-09-12.
  4. ^ BGS. "Digital Geology – Bedrock geology theme". Archived from the original on 13 December 2009. Retrieved 2009-11-12.
  • Rafferty, John P. "Bedrock GEOLOGY". Encyclopedia Britannica. Encyclopedia Britannica. Retrieved 1 April 2019.
  • Harris, Clay, The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Vol. 1. 5th ed. Farmington Hills, MI: Gale, 2014. p515-516.

External linksEdit

  •   Media related to Bedrock at Wikimedia Commons