Depression (geology)

From Wikipedia, the free encyclopedia

Depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms, and may be referred to by a variety of technical terms.

  • A graben is a down dropped and typically linear depression or basin created by rifting in a region under tensional tectonic forces.
  • A kettle is left behind when a piece of ice left behind in glacial deposits melts.[3]
  • A depression may result from the weight of overlying material such as an ice sheet during continental glaciation which is subsequently removed resulting in a basin which slowly rebounds. The area around the ice sheet, though not covered in ice itself, may also be pulled down by the weight of the ice sheet, which is known as peripheral depression.[9] Further from the ice, a forebulge may form, which is curved slightly upward.[10]
  • A depression may be a pothole - either a simple roadway depression or a fluvial erosional depression in a river streambed, or area affected by coastal water currents.

One of many impressive depressions is the Great Rift Valley of East Africa. Perhaps even more impressive is the Atlantic Ocean basin.

[edit] References

[edit] Citations

  1. ^ Collins, Allen; Whitney, Colleen; et al (2006-08-25). Geology - basin. UCMP Glossary. University of California, Berkeley. Retrieved on 2006-08-25.
  2. ^ a b Dictionary of Geologic Terms - B. geotech.org. Retrieved on 2006-08-25.
  3. ^ Dictionary of Geologic Terms - K. geotech.org. Retrieved on 2006-08-26.
  4. ^ Collins, Allen; Whitney, Colleen; et al (2006-08-25). Geology - sinkhole. UCMP Glossary. University of California, Berkeley. Retrieved on 2006-08-25.
  5. ^ Collins, Allen; Whitney, Colleen; et al (2006-08-25). Geology - caldera. UCMP Glossary. University of California, Berkeley. Retrieved on 2006-08-25.
  6. ^ Dictionary of Geologic Terms - C. geotech.org. Retrieved on 2006-08-25.
  7. ^ Collins, Allen; Whitney, Colleen; et al (2006-08-25). Geology - subduction. UCMP Glossary. University of California, Berkeley. Retrieved on 2006-08-25.
  8. ^ Collins, Allen; Whitney, Colleen; et al (2006-08-25). Geology - oceanic trench. UCMP Glossary. University of California, Berkeley. Retrieved on 2006-08-25.
  9. ^ Glossary of Important Terms in Glacial Geology - Peripheral Depression. Montana State University (1999). Retrieved on 2006-08-25. Cites American Geological Institute’s Glossary of Geology (3rd edition, revised in 1987).
  10. ^ Glossary of Important Terms in Glacial Geology - Forebulge. Montana State University (1999). Retrieved on 2006-08-25. Cites American Geological Institute’s Glossary of Geology (3rd edition, revised in 1987).