| Dictionary: col·lu·vi·um |
[Latin, a collection of washings, dregs, from colluere, to wash thoroughly : com-, intensive pref.; see com- + -luere, to wash.]
colluvial col·lu'vi·al adj.| 5min Related Video: colluvium |
| Geography Dictionary: colluvium |
The mixture of soil and unconsolidated rock fragments deposited on, or at the foot of, a slope.
| Archaeology Dictionary: colluvium |
General term for the accumulations of sediment carried by gravity down hill slopes, including material in the process of down-slope movement on hill sides, material trapped by barriers on hill slopes (included that behind fences, walls, or in lynchets), and deposits that build up at the foot of steep slopes and cliffs, generally in the form of fans and wedges. Old ground surfaces are often sealed beneath deposits of colluvium and can be especially important for archaeological preservation where the mechanisms that have given rise to the liberation of mobile sediments at the top of a slope (e.g. deforestation, cultivation) post-date the active use of the ground surface at the bottom.
| Wikipedia: Colluvium |
Colluvium is the name for loose bodies of sediment that have been deposited or built up at the bottom of a low-grade slope or against a barrier on that slope, transported by gravity. The deposits that collect at the foot of a steep slope or cliff are also known by the same name. Colluvium often outerfingers with alluvium (deposits transported downslope by water). Coarse deposits due to rockfall at a cliff base are called talus (scree) and if lithified are talus breccias. Avalanches, mudslides, and landslides are processes that deposit colluvium. This build-up process is called colluviation.
Colluvium normally forms humps at the base of mountains or fan-shaped deposits similar in shape to alluvial fans that cover former ground surfaces. This process is an important phenomenon in the fields of archaeology and soil science.
Many colluvial soils tend to have a fragipan associated with them that are a brittle subsoil layer typically high in clay. One theory of fragipan formation is the smearing of soil during the colluvial process causing the clays to seal the surface between the moving portion of soil and the stationary soil on which it slides. Ancient sites can be preserved beneath colluvium if later changes in the landscape such as deforestation encourage a downward movement of material.
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 | ploughwash (in archaeology) |
| slopewash (in archaeology) |
| bedrock (in archaeology) |
 | What is a colluvium? |
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Geography Dictionary. A Dictionary of Geography. Copyright © Susan Mayhew 1992, 1997, 2004. All rights reserved. Read more |
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| Archaeology Dictionary. The Concise Oxford Dictionary of Archaeology. Copyright © 2002, 2003 by Oxford University Press. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Colluvium". Read more |
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