Sedimentology

From Wikiversity
Jump to: navigation, search
This is an unsorted deposit with an extreme size range. Credit: Daniel Chapman.

Sedimentology is the science and study of sediments.

San Andreas.jpg Subject classification: this is a Geology resource.

With appropriate conditions, sediment is transformed into rock. These are the sedimentary rocks.

Theoretical sedimentology[edit]

Def. a "study of natural sediments and of the processes by which they are formed"[1] is called sedimentology.

Sediments[edit]

Def. a "collection of small particles, particularly dirt, that precipitates from a river or other body of water"[2] is called a sediment.

Bedrocks[edit]

Def. a "solid rock that exists at some depth below the ground surface"[3] is called a bedrock.

"Bedrock is rock "in place", as opposed to material that has been transported from another location by weathering and erosion."[3]

Usage notes

"In mountainous regions, bedrock can be seen at the surface. However, these occurrences are more properly called outcrops."[3]

Regoliths[edit]

Def. a "layer of loose rock, dust, sand, and soil, resting on the bedrock, that constitutes the surface layer"[4] is called a regolith.

Saprolites[edit]

Def. "a chemically weathered rock "[5] is called a saprolite.

Laterites[edit]

Def. a "red hard or gravel-like soil or subsoil [...] that has been leached of soluble minerals leaving insoluble iron and aluminium oxides and hydroxides"[6] is called a laterite.

Drifts[edit]

This shows morainic drift on the surface north of Brúarjökull. Credit: L.R. Bjarnadóttir.

Def. a "mass of matter which has been driven or forced onward together in a body, or thrown together in a heap"[7] is called drift.

The image on the right shows morainic drift on the surface north of the surge glacier Brúarjökull in Iceland.

Tills[edit]

This is glacial till exposed in a road cut with some small tufts of plants growing on it. Credit: Daniel Mayer.

Def. "glacial drift consisting of a mixture of clay, sand, pebbles and boulders"[8] is called till, or glacial till.

The image on the right shows glacial till exposed in a road cut with some plants growing on top.

Outwashes[edit]

Def. a "sediment (mostly sand and gravel) deposited by water flowing from a melting glacier"[9] is called an outwash.

Erratics[edit]

Def. a "rock moved from one location to another"[10] is called an erratic.

Landslides[edit]

This shows the La Conchita 1995 Landslide. Credit: USGS.

Def. "a movement of surface material down a slope"[11] is called a landslide.

Entrainment[edit]

Def. any "of several processes in which a solid or liquid is put into motion by a fluid"[12] is called entrainment.

Def. "of, relating to, or situated or occurring at the surface of a glacier"[13] is called supraglacial.

Def. occurring "or located within a glacier"[14] is called englacial.

Def. formed, "or occurring beneath a glacier or other body of ice"[15] is called subglacial.

Diamictons[edit]

Def. "nonsorted, noncalcareous terrigenous deposits composed of sand and/or larger particles dispersed through a muddy matrix"[16] are called diamictons.

Alluvium[edit]

Alluvium is loose gravel, sand, silt, or clay deposited by current or past streams. Credit: Sharon Reynolds, Arizona State University.

Def. "soil, clay, silt or gravel deposited by flowing water, as it slows, in a river bed, delta, estuary or flood plain"[17] is called alluvium.

Loess[edit]

This is loess. Credit: Mussklprozz.

Def. any "sediment, dominated by silt"[18] is called loess.

Def. fine-grained, "silt-size sediment formed by the mechanical erosion of bedrock at the base and sides of a glacier by moving ice"[19] is called rock flour.

"When [rock flour] enters a stream, it turns the stream's color brown, gray, iridescent blue-green, or milky white. [It is also] called Glacier Flour or Glacier Milk."[19]

Soils[edit]

Profile is of Oklahoma State Soil - Port silt loam. Credit: U.S. Department of Agriculture.

Def.

  1. a "mixture of sand and organic material, used to support plant growth",[20]
  2. an "unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants",[20] and
  3. an "unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time"[20]

is called a soil.

"The Port series [shown in the profile on the right] consists of very deep, well-drained, moderately permeable, nearly level and very gently sloping soils on flood plains that are subject to frequent, occasional, or rare flooding. These soils are in western and central Oklahoma. They are in 33 of the 77 counties and make up about 1 million acres."[21]

"These soils formed in calcareous, loamy alluvium and under native grasses. A high volume of organic matter recycled in a grass ecosystem has resulted in good soil structure and tilth. Most areas of the soils are used as cropland. The main cultivated crops are alfalfa, wheat, grain sorghum, and cotton. Some areas are used as pasture or rangeland."[21]

Aeolianites[edit]

Holocene eolianite is on Long Island, Bahamas. Credit: Wilson44691.

Def. a "rock formed from dune sand, often calcareous"[22] is called an aeolianite.

Turbidites[edit]

Turbidites (interbedded with mudstones/siltstones) from the Ross Sandstone Formation. Credit: USGS.
Turbidite (Gorgoglione Flysch) is from Miocene, South Italy. Credit: Geologist.

Def. "sea-bottom deposits formed by massive slope failures where rivers have deposited large deltas"[23] are called turbidites.

"Turbidites [shown in the image on the right] are sea-bottom deposits formed by massive slope failures where rivers have deposited large deltas. These slopes fail in response to earthquake shaking or excessive sedimentation load. The temporal correlation of turbidite occurrence for some deltas of the Pacific Northwest suggests that these deposits have been formed by earthquakes."[23]

"Turbidites (interbedded with mudstones/siltstones) from the Ross Sandstone Formation Turbidite system of Namurian age in County Clare, Western Ireland. The sandstone beds were formed in a deep basin by turbidites coming from a delta area."[23]

Marginal marines[edit]

This is a marginal marine sequence from southwestern Utah, USA. Credit: Wilson44691.

The marginal marine sequence on the right has been dated to the Middle Triassic.

Alpine limestones[edit]

Layers of alpine limestone are dated to the Triassic. Credit: Gikü.

The middle Triassic layers of alpine limestone in the image on the right were deposited on the bottom of a shallow sea.

Physics[edit]

Def. "[a] particle classification system ... based on diameter"[24] is called the Wentworth scale.

Boulders[edit]

This image shows a rock apparently where it fell. Credit: Sten Porse.

Def. "[a] particle [or large piece of stone] greater than 256 mm in diameter [that can theoretically be moved if enough force is applied]"[25] is called a boulder.

Cobbles[edit]

Def. "[a] particle from 64 to 256 mm in diameter"[26] is called a cobble.

Pebbles[edit]

These are pebbles on a beach. Credit: Slomox.

Def.' "[a] particle from 4 to 64 mm in diameter"[27] is called a pebble.

Granules[edit]

Def. "[a] particle from 2 to 4 mm in diameter"[28] is called a granule.

Gravels[edit]

Gravel, largest fragment in this photo is about 4 cm, is from Thirasia, Santorini, Greece. Credit: .

Def. "[a] particle from 2 to 64 mm in diameter"[29] is called a gravel.

Sands[edit]

Close-up of sand from a beach in Vancouver, shows a surface area of approximately between 1-2 square centimetres. Credit: .

Def. "[a] particle from 62.5 microns to 2 mm in diameter"[30] is called a sand.

Muds[edit]

Def. "[a] particle less than 62.5 microns in diameter"[31] is called a mud.

Silts[edit]

Def. a "particle from 3.9 to 62.5 microns in diameter"[18] is called silt.

Clay[edit]

Quaternary clay in Estonia is 400,000 years old. Credit: Siim Sepp.

Def. a "particle less than 3.9 microns in diameter"[32] is called clay.

Colloids[edit]

Def. "[a] particle less than 1 micron in diameter"[33] is called a colloid.

See also[edit]

References[edit]

  1. SemperBlotto (18 August 2006). "sedimentology, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2014-11-09. 
  2. "sediment, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 29 October 2014. Retrieved 2014-12-05. 
  3. 3.0 3.1 3.2 "bedrock, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 7 July 2014. Retrieved 2014-12-05. 
  4. "regolith, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 25 May 2014. Retrieved 2014-12-05. 
  5. "Saprolite, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. 12 April 2014. Retrieved 2014-12-05. 
  6. "laterite, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 24 May 2014. Retrieved 2014-12-05. 
  7. "drift, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 18 October 2014. Retrieved 2014-12-03. 
  8. "till, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 17 November 2014. Retrieved 2014-12-04. 
  9. "outwash, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 17 April 2014. Retrieved 2014-12-05. 
  10. "erratic, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 13 August 2014. Retrieved 2014-12-05. 
  11. USGS (July 18, 2012). "Earthquake Glossary - landslide". Menlo Park, California USA: USGS. Retrieved 2014-12-02. 
  12. "entrainment, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 7 November 2013. Retrieved 2014-11-22. 
  13. "supraglacial, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 26 May 2014. Retrieved 2014-11-22. 
  14. "englacial, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 20 April 2011. Retrieved 2014-11-22. 
  15. "subglacial, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 1 February 2011. Retrieved 2014-11-22. 
  16. L. J. G. Schermerhorn (September 1966). "Terminology of Mixed Coarse-Fine Sediments: NOTES". Journal of Sedimentary Petrology 36 (3): 831-5. Retrieved on 2014-11-08. 
  17. SemperBlotto (12 August 2005). "alluvium, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2014-11-10. 
  18. 18.0 18.1 SemperBlotto (31 March 2006). "loess, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2014-11-10. 
  19. 19.0 19.1 Eleyne Phillips (16 December 2004). "Glossary of Glacier Terminology". Reston, Virginia USA: United States Geological Survey. Retrieved 2014-11-09. 
  20. 20.0 20.1 20.2 "soil, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 25 November 2014. Retrieved 2014-12-05. 
  21. 21.0 21.1 Natural Resources Conservation Service (05 December 2014). "Port -- Oklahoma State Soil". Washington, DC USA: U. S. Department of Agriculture. Retrieved 2014-12-05. 
  22. "aeolianite, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. 28 May 2014. Retrieved 2014-12-06. 
  23. 23.0 23.1 23.2 USGSTurbidites (July 24, 2012). "Earthquake Glossary - turbidites". Menlo Park, California USA: USGS. Retrieved 2014-12-02. 
  24. (September 13, 2012) "Wentworth scale". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  25. (September 21, 2012) "boulder". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  26. (September 1, 2012) "cobble". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  27. (October 16, 2012) "pebble". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  28. (October 16, 2012) "granule". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  29. (October 16, 2012) "gravel". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  30. (October 23, 2012) "sand". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  31. (October 23, 2012) "mud". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 
  32. Metaknowledge (17 March 2012). "clay, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2014-11-10. 
  33. (September 8, 2012) "colloid". Wiktionary. San Francisco, California: Wikimedia Foundation, Inc. Retrieved on 2012-10-23. 

External links[edit]