Scree


Scree

Scree, also called talus and detritic cone, is a term given to broken rock that appears at the bottom of crags, mountain cliffs or valley shoulders, forming a scree slope. The maximum inclination of such deposits corresponds to the angle of repose of the mean debris size.

The term "scree" comes from the Old Norse term for landslide, "skriða". [cite web|title=Scree|work=Online Etymology Dictionary|url=http://www.etymonline.com/index.php?term=scree|accessdate=2006-04-20]

The term "scree" is sometimes used interchangeably with "talus", though scree refers to small rocks, like mixed size gravel and loose as dirt (e.g., anything smaller than a human fist), while talus can refer to rocks larger than scree. [cite web|title=Scree|work=Backpacker Magazine article on mountain skills.|url=http://www.backpacker.com/june_2001_skills_mountain_hiking_skills/article/2154?page=2|accessdate=2008-04-22] Going downhill on sturdy boots one is often able to slip-slide down a scree slope. Uphill takes more effort because one tends to slide a bit with every step. Talus is easier for stepping up, but not suitable for sliding down.

The formation of scree is often a result of frost heaving, one of the physical weathering processes that slowly wear mountains down. During the day, water can flow into cracks and crevices in the rock. If the temperature drops sufficiently, for example with the onset of evening, the water freezes. Since water expands when it freezes, it forms a powerful wedge which can eventually break out pieces of rock. A repeated cycle of freeze-thaw can lead to significant erosion and most of the loose rock or scree slopes so common in the mountains have been formed in this way.

For mountaineers screes may pose a danger. In a similar way, gravity causes an almost constant scree inclination by the impulse of falling rocks.

Formation of scree can occur on planets or moons other than the Earth. For example it is fairly common for fresh craters on the Moon to have piles of talus along the base of the inner wall.

Scree can also be the result of human activity, such as the scree beneath the sculpture Mount Rushmore in South Dakota.

ee also

* Angle of repose
* Cirque (landform)
* Gravel
* Mass wasting
* Landslide

References


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Look at other dictionaries:

  • Scree — (skr[=e]), n. A pebble; a stone; also, a heap of stones or rocky d[ e]bris. [Prov. Eng.] Southey. [1913 Webster] …   The Collaborative International Dictionary of English

  • scree — [skri:] n [Date: 1700 1800; : Old Norse; Origin: skritha landslide ] an area of loose soil and broken rocks on the side of a mountain ▪ a scree slope …   Dictionary of contemporary English

  • scree — scree; scree·man; …   English syllables

  • scree — [ skri ] noun 1. ) uncount small loose pieces of broken rock at the bottom of a cliff or along the slopes of a mountain 2. ) count a slope covered with small pieces of rock …   Usage of the words and phrases in modern English

  • scree — 1781, back formation from screes (pl.) pebbles, small stones, from O.N. skriða landslide, from skriða to slide, glide, from P.Gmc. *skrithanan (Cf. O.E. scriþan to go, glide, O.S. skridan, Du. schrijden, O.H.G. scritan, Ger. schreiten to stride ) …   Etymology dictionary

  • scree — ► NOUN ▪ a mass of small loose stones that form or cover a slope on a mountain. ORIGIN probably from Old Norse, landslip …   English terms dictionary

  • scree — [skrē] n. [back form. < pl. screes < earlier screethes < ON skritha, landslide < skritha, to slide, creep, akin to Ger schreiten, to step < IE base * (s)ker , to turn, bend] TALUS2 (sense 2) …   English World dictionary

  • scree — 1. noun /ˈskɹiː/ a) Loose stony debris on a slope. Occasional rounds zinged off the scree, each with a different pitch. b) A slope of such material at the base of a cliff, etc. The next landmark was an apachita cairn, at the top of a steep scree …   Wiktionary

  • scree — [[t]skri͟ː[/t]] screes N VAR Scree is a mass of loose stones on the side of a mountain. Occasionally scree fell in a shower of dust and noise... He scrambled sideways down the scree slope …   English dictionary

  • scree —    A collective term for an accumulation of coarse rock debris or a sheet of coarse debris mantling a slope. Scree is not a synonym of talus, as scree includes loose rock fragments on slopes without cliffs.    Compare: talus, colluvium, mass… …   Glossary of landform and geologic terms


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