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 grades into 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.

Sources

• Thomas Madigan, "The Geology of the MNRRA Corridor", p. 26, National Park Service, Retrieved July 23, 2007

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This soil science-related article is a stub. You can help Wikipedia by expanding it.v · Categories: Geomorphology Sedimentology Geomorphology stubs Soil science stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем написать реферат Hypernatremia International (New Order album) Look at other dictionaries: Colluvium — Colluvium,   Geologie: Kolluvium …   Universal-Lexikon colluvium — [kə lo͞o′vē əm] n. pl. colluvia [kə lo͞o′vēə] or colluviums [ML, altered < L colluvies, dregs, sweepings < colluere, to wash out < col , var. of com ,COM + luere, var. of lavare, to LAVE1] rock fragments, sand, etc. that accumulate on… …   English World dictionary Colluvium filled bedrock hollow — Colluvium filled bedrock hollows are the cause of many shallow earth landslides in steep mountainous terrain. They can form as a U or a V shaped trough as local bedrock variations reveal areas in the bedrock which are more prone to weathering… …   Wikipedia colluvium — noun (plural colluvia or viums) Etymology: New Latin, from Medieval Latin, offscourings, alteration of Latin colluvies, from colluere to wash, from com + lavere to wash more at lye Date: circa 1936 rock detritus and soil accumulated at the foot… …   New Collegiate Dictionary colluvium — colluvial, adj. /keuh looh vee euhm/, n., pl. colluvia / vee euh/, colluviums. Geol. loose earth material that has accumulated at the base of a hill, through the action of gravity, as piles of talus, avalanche debris, and sheets of detritus moved …   Universalium colluvium — noun A loose accumulation of rock and soil debris at the foot of a slope …   Wiktionary colluvium —    Unconsolidated, unsorted earth material being transported or deposited on side slopes and/or at the base of slopes by mass movement (e.g., direct gravitational action) and by local, unconcentrated runoff.    Compare: alluvium, slope alluvium,… …   Glossary of landform and geologic terms colluvium — col·lu·vi·um …   English syllables colluvium — col•lu•vi•um [[t]kəˈlu vi əm[/t]] n. pl. vi•a [[t] vi ə[/t]] vi•ums gel loose earth material that has accumulated at the base of a slope; talus • Etymology: 1935–40; < L colluv , base of colluere to rinse, wash out < lavere to wash; cf.… …   From formal English to slang colluvium — /kɒˈluviəm/ (say ko loohveeuhm) noun loose and incoherent deposits, usually at the foot of a slope or cliff line and brought by gravity. {Latin, from colluere wash thoroughly} –colluvial, adjective …   18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”