Ingeography, aplain, commonly known asflatland, is a flat expanse of land that generally has few rapid or steep changes inelevation. Natural vegetation in plains can includeprairies/grasslands,forests,savanah,tundra, anddesert biomes, among others. Plains occur aslowlands alongvalleys or at the base ofmountains, ascoastal plains, and asplateaus oruplands. Plains are one of the majorlandforms on earth, being present on all continents and covering more than one-third of the world's land area. Plains in many areas are important foragriculture. There are various types of plains, andbiomes on them.
A plain or flatland is a flat expanse of land with few rapid or steep changes in elevation. Plains occur aslowlands alongvalleys or at the base ofmountains, ascoastal plains, and asplateaus oruplands.[1] Plains are one of the majorlandforms on earth, where they are present on all continents, and cover more than one-third of the world's land area.[2]
In a valley, a plain is enclosed on two sides, but in other cases a plain may be delineated by a complete or partial ring of hills, by mountains, or bycliffs. Where a geological region contains more than one plain, they may be connected by apass (sometimes termed agap). Coastal plains mostly rise fromsea level until they run into elevated features such as mountains or plateaus.[3] Plains can be formed from flowinglava; fromdeposition of sediment by water, ice, or wind; or formed byerosion by the agents from hills or mountains.
Plains in many areas are important foragriculture because where the soils were deposited assediments they may be deep andfertile, and the flatness facilitates mechanization of crop production; or because they support grasslands which provide good grazing forlivestock.[5]
Alluvial plains, which are formed by rivers and which may be one of these overlapping types:
Alluvial plains, formed over a long period of time by ariver depositing sediment on their flood plains or beds, which becomealluvial soil. The difference between a flood plain and an alluvial plain is: a flood plain represents areas experiencing flooding fairly regularly in the present or recently, whereas an alluvial plain includes areas where a flood plain is now and used to be, or areas which only experience flooding a few times a century.[8]Chengdu Plain,Sichuan
Flood plain, adjacent to a lake, river, stream, or wetland that experiences occasional or periodicflooding.
Glacial plains, formed by the movement of glaciers under the force of gravity:
Outwash plain (also known as sandur; plural sandar), a glacial out-wash plain formed of sediments deposited by melt-water at the terminus of a glacier. Sandar consist mainly of stratified (layered and sorted) gravel and sand.[9][10]
Till plains, plain ofglacial till that form when a sheet ofice becomes detached from the main body of aglacier and melts in place depositing thesediments it carries. Till plains are composed of unsorted material (till) of all sizes.
Lacustrine plains, plains that originally formed in a lacustrine environment, that is, as the bed of alake.[11]
Erosional plains have been leveled by various agents of denudation such as running water, rivers, wind and glacier which wear out the rugged surface and smoothens them. Plain resulting from the action of these agents of denudation are calledpeneplains (almost plain) while plains formed from wind action are calledpediplains.[13]
Structural plains are relatively undisturbed horizontal surfaces of the Earth. They are structurally depressed areas of the world that make up some of the most extensive natural lowlands on the Earth's surface.[14]
ThePampas are a huge area of fertilegrasslands in the southeastern area of South America, bordering the Atlantic OceanNineveh Plains (Bozan, Iraq)A field plain inLiminka,FinlandView of Fields atBiccavolu, Eastern coastal plains,Andhra Pradesh, IndiaYilan Plain, TaiwanView of the South Småland peneplain atStore Mosse National Park in Sweden.North Somerset Levels taken fromDolebury Warren, England, UKTerrain near the central German town ofFulda.The Wallachian Plain, in the southern part ofArgeș County.View of Messara from the hill ofPhaestus, Greece.Cumberland Plainbushland inWestern Sydney, Australia.Looking southeast across the Taieri Plain, Otago,New Zealand.
^Rood, Stewart B.; Pan, Jason; Gill, Karen M.; Franks, Carmen G.; Samuelson, Glenda M.; Shepherd, Anita (2008-02-01). "Declining summer flows of Rocky Mountain rivers: Changing seasonal hydrology and probable impacts on floodplain forests".Journal of Hydrology.349 (3–4):397–410.Bibcode:2008JHyd..349..397R.doi:10.1016/j.jhydrol.2007.11.012.
^Whittow, John (1984).Dictionary of Physical Geography. London: Penguin. p. 467.ISBN978-0-14-051094-2.
^Gornitz, Vivien, ed. (2009).Encyclopedia of Paleoclimatology And Ancient Environments. Dordrecht: Springer. p. 665.ISBN9781402045516.
^Powell, W. Gabe. 2009. Identifying Land Use/Land Cover (LULC) UsingNational Agriculture Imagery Program (NAIP) Data as a Hydrologic Model Input for Local Flood Plain Management. Applied Research Project, Texas State University.
^Goudie, A. S., ed. (2004). "Denudation chronology".Encyclopedia of Geomorphology. pp. 244–248.
^Vinogradova, N.G. (1997). "Zoogeography of the Abyssal and Hadal Zones".The Biogeography of the Oceans. Advances in Marine Biology. Vol. 32. pp. 325–387.doi:10.1016/S0065-2881(08)60019-X.ISBN9780120261321.
^Magilligan F.J., Gomez B., Mertes L.A.K., Smith, L.C. Smith N.D., Finnegan D., Garvin J.B.,Geomorphic effectiveness, sandur development, and the pattern of landscape response during jökulhlaups:Skeiðarársandur, southeastern Iceland, Geomorphology 44 (2002) 95–113
^Smith L.C., Sheng Y., Magilligan F.J., Smith N.D., Gomez B., Mertes L., Krabill W.B., Garven J.B.,Geomorphic impact and rapid subsequent recovery from the 1996 Skeiðarársandur jökulhlaup, Iceland, measured with multi-year airborne lidar. Geomorphology vol. 75 Is. 1–2 (2006) 65–75
^United States. Department of Conservation. Division of Geology. Glacial Sluceways and Lacustrine Plains of Southern Indiana. By William D. Thornburry. Bloomington: n.p., 1950. Web. <"Archived copy"(PDF).Archived(PDF) from the original on 2016-03-03. Retrieved2015-12-16.{{cite web}}: CS1 maint: archived copy as title (link)>.
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