Nivation
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(nī′vā·shən)
(geology) Rock or soil erosion beneath a snowbank or snow patch, due mainly to frost action but also involving chemical weathering, solifluction, and meltwater transport of weathering products. Also known as snow patch erosion.
Oxford Dictionary of Geography:
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nivation
The effects of snow on a landscape. These include abrasion and freeze-thaw. Furthermore, melted snow triggers mass movements such as solifluction and slope wash. These processes may produce the shallow pits known as nivation hollows. In time, these hollows may trap more snow and may deepen further with more nivation so that cirques or thermocirques are formed. Nivation is 2-3 times as active on shaded, pole-facing slopes. See aspect. Snow has the greatest effect on a landscape where it is thin and melting.
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nivation
IN BRIEF: Erosion of rock or soil caused by alternating thawing and freezing.
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Wikipedia on Answers.com:
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Nivation
Nivation is a collective name for the different processes that occur under a snow patch. The primary processes are mass wasting and the freeze and thaw cycle,[1] in which fallen snow gets compacted into firn or névé. The importance of the processes covered by the term nivation with regard to the development of periglacial landscapes is increasingly questioned by scholars, and the use of the term is discouraged.[2] The term glacier is applied only when ice has accumulated enough for the mass to achieve motion.[3]
Nivation has come to include various subprocesses related to snow patches which may be immobile or semi-permanent. These sub-processes include erosion (if any) or initiation of erosion, weathering, and meltwater flow from beneath the snow patch.[3]
Weathered particles are moved downslope by creep, solifluction and rill wash.[1] Over time, this leads to the formation of nivation hollows which, when enlarged, can be the beginnings of a cirque.[1]
References
- ^ a b c Easterbrook, Don J. (1999). Surface Processes and Landforms (2nd ed.). New Jersey: Prentice Hall. p. 334. ISBN 0-13-860958-6.
- ^ André, Marie-Françoise (2002). "Do periglacial landscapes evolve under periglacial conditions?". Geomorphology 1-2 (52): 149–164. doi:10.1016/S0169-555X(02)00255-6.
- ^ a b Potter, Franklin C. (September, 1949), "Nivation", Crater Lake Nature Notes XV (1), http://www.nps.gov/archive/crla/notes/vol15b.htm#3
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