For other uses, see Mountain (disambiguation). The Matterhorn, Swiss Alps Five Finger Mountain, Azerbaijan. A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them. The study of mountains is called Orography. Exogeology deals with planetary mountains, which in that branch of science are usually called montes (singular—mons). The highest mountain on earth is the Mount Everest 8,848 m (29,029 ft). The highest known mountain in the Solar System is Olympus Mons on the planet Mars at 21,171 m (69,459 ft). Contents 1 Definition 2 Characteristics 3 Types 3.1 Man-made 4 Geology 5 Gallery 6 See also 7 Notes 8 Further reading 9 External links // Definition The view of Jeff Davis Peak from the glacier-carved summit of Wheeler Peak, Nevada. Because Boundary Peak, Nevada is partially in California, and is actually a sub-peak of Montgomery Peak, the shorter Wheeler Peak can be considered the tallest mountain in Nevada. There is no universally accepted definition of a mountain. Elevation, volume, relief, steepness, spacing and continuity has been used as criteria for defining a mountain.1 In the Oxford English Dictionary a mountain is defined as "a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which, relatively to the adjacent elevation, is impressive or notable."1 Whether a landform is called a mountain may depend on usage among the local people. The highest point in San Francisco, California, is called Mount Davidson, notwithstanding its height of 300 m (980 ft), which makes it ten feet short of the minimum for a mountain in American appellation. Similarly, Mount Scott outside Lawton, Oklahoma is only 251 m (823 ft) from its base to its highest point.

Definitions of "mountain" include:2 Height over base of at least 2,500 m (8,202 ft). Height over base of 1,500 m (4,921 ft).–2,500 m (8,202 ft). with a slope greater than 2 degrees Height over base of 1,000 m (3,281 ft).–1,500 m (4,921 ft). with a slope greater than 5 degrees Local (radius 7,000 m (22,966 ft). elevation greater than 300 m (984 ft)., or 300 m (984 ft)–1,000 m (3,281 ft). if local (radius 7,000 m (22,966 ft). elevation is greater than 300 m (984 ft). By this definition, mountains cover 64% of Asia, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous and 10% of people live in mountainous regions.3 Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.45 Characteristics Mountain in Carbon County, Utah High mountains, reach into the colder layers of the atmosphere. They are consequently subject to glaciation, and erosion through frost action. Such processes produce the peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan. Mountains can be eroded and weathered, altering their characteristics over time. Mount Olympus in Greece. Tall mountains have different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes. At the highest elevations, trees cannot grow, and whatever life may be present will be of the alpine type, resembling tundra.6 Just below the tree line, one may find subalpine forests of needleleaf trees, which can withstand cold, dry conditions.7 In regions with dry climates, the tendency of mountains to have higher precipitation as well as lower temperatures also provides for varying conditions, which in turn lead to differing flora and fauna.68 Some plants and animals found in these zones tend to become isolated since the conditions above and below a particular zone will be inhospitable and thus constrain their movements or dispersal. On the other hand, birds, being capable of flight, may take advantage of montane habitats and migrate into a region that would otherwise not provide appropriate habitat.9 These isolated ecological systems, or microclimates, are known as sky islands.10

The reason mountains are colder than lowlands has to do with how the sun heats the surface of the earth. Practically all the heat at the surface of the Earth comes from the sun, in the form of solar energy. The sun's radiation is absorbed by land and sea, whence the heat is transferred into the air. Air is an insulator, so conduction of heat from the ground to the atmosphere is negligible. Heat is mainly transferred into the atmosphere through convection and radiation. Warm air rises because of its buoyancy, leading to convective circulation, in the form of thermals, within the lowest layer of the atmosphere, the troposphere. When heat radiates from the surface of the earth, it is released as long-wave radiation, which does not travel through the air efficiently. This radiant heat is absorbed temporarily by gasses in the atmosphere, such as carbon dioxide and water vapor. Thus, the lower portion of the troposphere—more than 50% of all air lies below the altitude of the summit of Mt. Everest—forms a blanket of air keeping the surface warm. This is the Greenhouse Effect. The higher one goes in altitude, the less of this blanket there is to keep in the heat. Thus, higher elevations, such as mountains, are colder than surrounding lowlands.11 Air temperature in the lowest layer of the atmosphere, the troposphere, decreases with gains in altitude. The rate at which the temperature drops with elevation, called the environmental lapse rate, is not constant (it can fluctuate throughout the day or seasonally and also regionally), but a normal lapse rate is 5.5°C per 1,000 m (3°F per 3,000 ft).1213 The temperature continues to drop up to a height of about 9–16 km, where it does not decrease further. However, this is higher than the highest mountaintop. Mountains are generally less preferable for human habitation than lowlands; the weather is often harsher, and there is little level ground suitable for agriculture. At very high altitudes, there is less oxygen in the air and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia—a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3,500 meters (11,483 ft).

Many mountains and mountain ranges throughout the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility is affected by height, steepness, latitude, terrain, weather. Roads, lifts, or tramways affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts. Mountains are made up of earth and rock materials. The outermost layer of the Earth or the Earth's crust is composed of six plates. When two plates move or collide each other, vast land areas are uplifted, resulting in the formation of mountains. Types This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2010) This section may need to be wikified to meet Wikipedia's quality standards. Please help by adding relevant internal links, or by improving the section's layout. (October 2010) Classified by the geological processes that shape them, there are five major types of mountains: Fold mountains Fold mountains are the most common type of mountains. Examples of fold mountains are the Himalayas (Asia), the Alps (Europe). They are formed due to collision of two plates, causing folding of the Earth's crust. The fold that descends on both sides is called anticline; whereas, the fold that ascends from a common low point (on both sides) is called syncline. Fault-Block mountains As the name suggests, fault-block mountains or fault mountains are formed when blocks of rock materials slide along faults in the Earth's crust. There are two types of block mountains, namely the lifted and tilted. In the former type, the mountain has two steep sides; whereas, the tilted type has one steep side and gentle sloping side. Example of fault-block mountain is the Sierra Nevada mountains (North America). Volcanic mountains Volcanic mountains are formed due to volcanic eruptions, for e.g. Mount Fuji (Japan). They are formed when volcanic magma erupts and piles up on the surface of the Earth. Dome mountains Dome mountains are formed when the hot magma rises from the mantle and uplifts the overlying sedimentary layer of the Earth's crust. In the process, the magma is not erupted, but it cools down and forms the core of the mountain. Example of dome mountain is the Navajo Mountain in Utah. They are called dome mountains due to their appearance that resembles dome shape. Plateau mountains Plateau mountains are pseudo mountains that are formed because of erosion. An example of plateau mountain is the Catskill Mountains (New York). They usually occur near the fold mountain ranges.

Some mountains are formed as a result of several of the Earth's forces. Though the Rockies in North America is formed due to folding, there are mountains in the same range that are formed by faulting and doming. In nature, there is a continuous process of glaciation, soil erosion, and mechanical and chemical weathering, which altogether play a major role in altering the shape and characteristics of mountains. Man-made The Berg is a proposed man-made mountain in Berlin of around 1000 metres. Geology The Himalayan mountain range with Mount Everest. Main article: Orogeny A mountain is usually produced by the movement of lithospheric plates, either orogenic movement or epeirogenic movement. The compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, a mountain. The absolute heights of features termed mountains and hills vary greatly according to an area's terrain. The major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Two types of mountain are formed depending on how the rock reacts to the tectonic forces—block mountains or fold mountains. Compressional forces in continental collisions may cause the compressed region to thicken, so the upper surface is forced upward. To balance the weight of the earth surface, much of the compressed rock is forced downward, producing deep "mountain roots" [see the Book of "Earth", Press and Siever page.413]. Mountains therefore form downward as well as upward (see isostasy). However, in some continental collisions part of one continent may simply override part of the others, crumpling in the process. Some isolated mountains were produced by volcanoes, including many apparently small islands that reach a great height above the ocean floor. Blue Ridge Mountains in Shenandoah National Park, Virginia, USA

Block mountains are created when large areas are widely broken up by faults creating large vertical displacements. This occurrence is fairly common. The uplifted blocks are block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley. These areas often occur when the regional stress is extensional and the crust is thinned. The mid-ocean ridges are often referred to as undersea mountain ranges due to their bathymetric prominence. Rock that does not fault may fold, either symmetrically or asymmetrically. The upfolds are anticlines and the downfolds are synclines: in asymmetric folding there may also be recumbent and overturned folds. The Jura Mountains are an example of folding. Over time, erosion can bring about an inversion of relief: the soft upthrust rock is worn away so the anticlines are actually lower than the tougher, more compressed rock of the synclines. Gallery Mount Everest, 8,848 metres (29,029 ft), Himalayas, Nepal, China. K2, 8,611 metres (28,251 ft), Gilgit-Baltistan, Pakistan. Nilkantha (mountain), 6,597 metres (21,644 ft), Himalayas, India. Mount Kilimanjaro, 5,895 metres (19,341 ft), Tanzania. Musala, Rila mountain, 2,925 metres (9,596 ft), the highest peak in Bulgaria and the entire Balkan Peninsula Mount Feathertop, 1,922 metres (6,306 ft), Great Dividing Range, Victoria, Australia Pilot Mountain, 738 metres (2,421 ft), Sauratown Mountains, North Carolina, United States Northern Appalachian Mountains, Chic-Choc Range, Gaspé Peninsula, Quebec, Canada Yu Shan (Jade Mountain), 3,952 metres (12,966 ft), Taiwan.

Finsteraarhorn, 4,274 metres (14,022 ft), Bernese Alps, Switzerland. Sugarloaf Mountain, Brazil, 396 metres (1,299 ft), Rio de Janeiro, Brazil. Table Mountain, 1,085 metres (3,560 ft), Cape Town, South Africa Tangkuban Parahu mountain in Bandung, West Java, Indonesia The Zugspitze, the highest mountain in Germany, The Durmitor, the highest mountain in Montenegro Snowdon, the highest mountain in Wales The Sphinx, Bucegi, Romania Mount Aamadablam, Himalayas,8,812 metres (28,911 ft) Nepal See also Environment portal Ecology portal List of mountains List of mountain types Category:Lists of mountains Mountain range List of mountain ranges List of highest mountains List of peaks by prominence Latin names of mountains List of ski areas and resorts Mountaineering Mountain building Notes ^ a b Gerrard, A. J. 1990. Mountain Environments ^ Blyth, S., Groombridge, B., Lysenko, I., Miles, L. & Newton, A. (2002). "Mountain Watch". UNEP World Conservation Monitoring Centre, Cambridge, UK. http://www.unep-wcmc.org/mountains/mountain_watch/pdfs/WholeReport.pdf. Retrieved 2009-02-17.  ^ Panos (2002). "High Stakes". http://www.panos.org.uk/?lid=278. Retrieved 2009-02-17.  ^ "International Year of Freshwater 2003". http://www.wateryear2003.org/en/ev.php-URL_ID=3903&URL_DO=DO_TOPIC&URL_SECTION=201.html. Retrieved 2006-12-07.  ^ "The Mountain Institute". http://www.mountain.org/mountains/whymtns.cfm?slidepage=water. Retrieved 2006-12-07.  ^ a b "Biotic Communities of the Colorado Plateau: C. Hart Merriam and the Life Zones Concept". http://cpluhna.nau.edu/Biota/merriam.htm. Retrieved 30 January 2010.  ^ "Tree". Microsoft Encarta Reference Library 2003. Microsoft Corporation. 1993-2002. 60210-442-1635445-74407.  ^ "Mountain Environments". United Nations Environment Programme World Conservation Monitoring Centre. http://www.unep-wcmc.org/mountains/mountain_watch/pdfs/mountainEnvironments.pdf. Retrieved 30 January 2010.  ^ Taylor, Richard Cachor (2005). A Birder's Guide to Southeastern Arizona. American Birding Association. pp. 2–4. ISBN 1-878788-22-1.  ^ Tweit, Susan J. (1992). The Great Southwest Nature Factbook. Alaska Northwest Books. pp. 138–141. ISBN 0-88240-434-2.  ^ Lutgens, Frederick K.; Tarbuck, Edward J. (1998). The Atmosphere: An Introduction to Meteorology. Prentice Hall. pp. 15–17, 30–35, 38–40. ISBN 0-13-742974-6.  ^ "Temperature". Microsoft Encarta Reference Library 2003. Microsoft Corporation. 1993-2002. 60210-442-1635445-74407.  ^ "Atmosphere". Microsoft Encarta Reference Library 2003. Microsoft Corporation. 1993-2002. 60210-442-1635445-74407.  Further reading Fraknoi, A., Morrison, D., & Wolff, S. (2004). Voyages to the Planets. 3rd Ed. Belmont: Thomson Books/Cole. External links Wikiquote has a collection of quotations related to: Mountains Wikimedia Commons has media related to: Gallery of mountains Wikisource has the text of the 1911 Encyclopædia Britannica article Mountain. v · d · eEarth's landforms List of landforms Mountainous landforms Mountain · Mountain range · Plateaus · Hills · Valley Continental plain Plain · Tundra · Ice sheets River landform River · River Delta · Lakes · Meanders · Waterfalls · Rapids · River valley Fluvial landforms Alluvial fan · Beach · Canyons · Channel · Cave · Cliff · River Delta · Floodplain · Levee · Oasis · Swamp · Ponds Glacial landforms Arête · Cirques · Eskers · Fjords · Glacier · Tunnel valley Oceanic and coastal landforms Atoll · Bay · Channels · Coast · Continental shelf · Coral reef · Estuary · Lagoons · Mid-ocean ridge · Oceanic trench · Peninsula · Isthmus · Islands · Sea mount Volcanic landforms Volcanoes · Caldera · Crater Lake  · Geyser · Hotspot · Oceanic ridges · Lava plain · Lava plateaus · Volcanic crater · Plugs · Wall rock · Lava dome · Submarine volcano (Guyot) Aeolian landforms Desert · Tundra · Dry lake · Dunes · Sandhill Artificial landforms Building · Bridge · Canals (man-made channels) · Dams · Dikes · Artificial Lakes · Polder · Artificial islands · Artificial reef · Tunnel · Quarry · Ditch · Road · Reclaimed land see also Geographical feature