Mountain Glossary

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See Landform Gallery for definitions with images

Contents

[edit] A

  • Alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms.
  • Aquifer A formation, group of formations, or part of a formation that contains sufficient saturated, permeable material to yield significant quantities of water to wells and springs.
  • Arete a steep-sided, sharp-edged bedrock ridge formed by two glaciers eroding away on opposite sides of the ridge.

[edit] B

  • Bergschrund is a deep and often wide gap or crevasse, or series of closely spaced crevasses, in ice or firn at or near the head of a valley glacier. A bergschrund separates the moving ice and snow from the relatively immobile ice and snow adhering to the headwall of a valley (or cirque).
  • Berm an artificial ridge or embankment or a narrow path: a ledge or narrow path along the top or bottom of a slope, at the edge of a road, or along a canal.
  • Boulder is a rock with grain size of usually no less than 256 mm (10 inches) diameter. While a boulder may be small enough to move or roll manually, others are extremely massive. In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks or stones.
  • Biome are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems.
  • Butte is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top; it is smaller than mesas, plateaus, and tables. In some regions, such as the north central and northwestern United States, the word is used for any hill. The word "butte" comes from a French word meaning "small hill"; its use is prevalent in the western United States, including the southwest, where "mesa" is also used.

[edit] C

  • Canyon (occasionally spelled cañon) or gorge is a deep ravine between cliffs often carved from the landscape by a river.
  • Cirque A steep-walled mountain basin which usually forms the blunt end of a valley. (French for "circus.")
  • Chemical weathering is the chemical decomposition of geological material (e.g., rocks, soil parent material) by a variety of chemical process like oxidation, hydrolysis, and carbonation. Chemical weathering alters the chemistry of the weathered material, whereas physical weathering does not.
  • Col A dip in a ridge that forms a small, high pass.
  • Cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually formed by rock that is resistant to erosion and weathering.
  • Crevasses cracks in the glacial ice. The upper 30 meters of glacial ice is somewhat brittle, and as the glacier flows, cracks develop. Crevasses rarely extend to depths below approximately 30 meters because the ice below that too plastic and the cracks close.

[edit] E

  • Erosion is the process of weathering and transport of solids (sediment, soil, rock and other particles) in the natural environment or their source and deposits them elsewhere. It usually occurs due to transport by wind, water, or ice; by down-slope creep of soil and other material under the force of gravity; or by living organisms, such as burrowing animals, in the case of bioerosion.

[edit] F

  • Foothills are geographically defined as gradual increases in hilly areas at the base of a mountain range. They are a transition zone between plains and low relief hills to the adjacent topographically high mountains. Many neighborhoods and communities found in such a location are termed "the foothills".
  • Frost heaving (or a frost heave) results from ice forming beneath the surface of soil during freezing conditions in the atmosphere. The ice grows in the direction of heat loss (vertically toward the surface) starting at the freezing front or boundary in the soil, it requires a water supply to keep feeding the ice crystal growth, and the growing ice is restrained by overlying soil, which applies a load that limits its vertical growth and promotes the formation of a lens-shaped area of ice within the soil.
  • Frozen Ground is Soil or Rock in which part or all of the pore water has turned into ice. Frozen ground occurs when the ground contains water, and the temperature of the ground goes down below Celsius (32° Fahrenheit). It can make a big difference if the ground stays frozen all year, or if the ground freezes and thaws.

[edit] G

  • Glacial erratic is a piece of rock that differs from the size and type of rock native to the area in which it rests. "Erratics" take their name from the Latin word errare, and are carried by glacial ice, often over distances of hundreds of kilometres. Erratics can range in size from pebbles to large boulders such as Big Rock (16,500 tons) in Alberta.
  • Glacial lake is a lake with origins in a melted glacier. Near the end of the last ice age, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often leaves behind large deposits of ice in hollows between drumlins or hills. As the ice age ends, these will melt to create lakes.
  • Glacier is a perennial mass of ice which moves over land.
  • Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal and industrial use by constructing and operating extraction wells.
  • Gully is a landform created by running water eroding sharply into soil, typically on a hillside. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width. When the gully formation is in process, the water flow rate can be substantial, which causes the significant deep cutting action into soil.

[edit] H

  • Hanging Valley: a valley eroded by a small tributary glacier, such that the elevation of the valley floor is higher than the elevation of the valley floor that the hanging valley joins. The erosive power of glaciers is dictated by their size: the larger a glacier, the farther down into the landscape it can erode. Thus the valley floors of small tributary glaciers will be higher in elevation that the valley floor of the larger glacier that the small tributary glacier joins.
  • Hill is a landform that extends above the surrounding terrain. Hills often have a distinct summit, although in areas with scarp/dip topography a hill may refer to a particular section of scarp slope without a well-defined summit.

[edit] I

  • Ice Fall: the ice equivalent of a waterfall. As ice flows over a drop-off, it may break apart and then reform at the base of the drop-off.
  • Ice field (also spelled icefield) is an area less than 50,000 km² (19,305 mile²) of ice often found in the colder climates and higher altitudes of the world where there is sufficient precipitation. It is an extensive area of interconnected valley glaciers from which the higher peaks rise as nunataks. Ice fields are larger than alpine glaciers, smaller than ice sheets and similar in area to ice caps.

[edit] L

  • Lake (from Latin lacus) is a terrain feature (or physical feature), a body of liquid on the surface of a world that is localized to the bottom of basin (another type of landform or terrain feature; that is, it is not global).
  • Land mass refers to the total area of a country or geographical region (which may include discontinuous pieces of land such as islands). The Earth's total land mass is 148,939,063.133 km² (57,511,026.002 square miles) which is about 29.2% of its total surface. Water covers approximately 70.8% of the Earth's surface, mostly in the form of oceans.
  • Landform or physical feature comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography. Landform elements also include seascape and oceanic waterbody interface features such as bays, peninsulas, seas and so forth, including sub-aqueous terrain features such as submersed mountain ranges, volcanoes, and the great ocean basins.
  • Landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments. Although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability. Typically, pre-conditional factors build up specific sub-surface conditions that make the area/slope prone to failure, whereas the actual landslide often requires a trigger before being released.

[edit] M

  • Monadnock or inselberg is an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain. The term "monadnock" is usually used in the United States, whereas "inselberg" is the more common international term.
  • 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.
  • Mountain range is a chain of mountains bordered by highlands or separated from other mountains by passes or valleys. Individual mountains within the same mountain range do not necessarily have the same geology, though they often do; they may be a mix of different orogeny, for example volcanoes, uplifted mountains or fold mountains and may, therefore, be of different rock.
  • Moraine is any glacially formed accumulation of unconsolidated glacial debris (soil and rock) which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past ice age

[edit] N

  • Nunatak (from Inuit nunataq) is an exposed, often rocky element of a ridge, mountain, or peak not covered with ice or snow within (or at the edge of) an ice field or glacier. The term is typically used in areas where a permanent ice sheet is present. Nunataks present readily identifiable landmark reference points in glaciers or ice caps and are often named.

[edit] O

  • Overburden is the material that lies above the area of economic or scientific interest (in mining and archaeology) e.g., the rock, soil and ecosystem that lies above the coal seam or ore body. Overburden may also be used as a term to describe all soil and ancillary material above the bedrock horizon in a given area.
  • Ogives are broad banded surface patterns that generally curve down-glacier as a result of faster ice movement toward the center of a glacier. Ogives are common below icefalls.

[edit] P

  • Physical weathering is the disintegration of earth material without undergoing a chemical change. Physical weathering results in increased surface area for chemical reactions to occur on.
  • Plateau also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau.
  • Pyramidal peak, or sometimes in its most extreme form called a glacial horn, is a mountaintop that has been modified by the action of ice during glaciation and frost weathering. If the use is unambiguous within a mountain context, then the simple terms peak or horn may be used.

[edit] R

  • Ravine is a very small valley—almost like a canyon but narrower—which is often the product of streamcutting erosion. Ravines are typically classified as larger in scale than gullies, although smaller than valleys.
  • Ribbon lake is a long and narrow, finger-shaped lake, usually found in a glacial trough. Its formation begins when a glacier moves over an area containing alternate bands of hard and soft bedrock. The sharp-edged boulders that are picked up by the glacier and carried at the bottom of the glacier erode the softer rock more quickly by abrasion, thus creating a hollow called a rock basin. On either side of the rock basin, the more resistant rock is eroded less and these outcrops of harder rock are known as rock bars, which act as dams between which rainwater may accumulate after the retreat of the ice age, filling up the rock basin and creating a ribbon lake.
  • Ridge is a geological feature that features a continuous elevational crest for some distance. Ridges are usually termed hills or mountains as well, depending on size.
  • River A river is a natural watercourse, usually freshwater, flowing toward an ocean, a lake, a sea, or another river.
  • Rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids. The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic. The scientific study of rocks is called petrology, and petrology is an essential component of geology.

[edit] S

  • Saddle A high pass between two peaks.
  • Scree also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles. These deposits typically have a concave upwards form, while the maximum inclination of such deposits corresponds to the angle of repose of the mean debris size.
  • Serac (originally from Swiss French sérac, a type of ricotta-like whey cheese) is a block or column of ice formed by intersecting crevasses on a glacier. Often house-sized or larger, they are dangerous to mountaineers since they may topple with little warning. Even when stabilized by persistent cold weather, they can be an impediment to glacier travel.
  • Slope is used to describe the steepness, incline, gradient, or grade of a straight line. A higher slope value indicates a steeper incline.
  • Snow line The lowest elevation area of a perennial snow field on high terrain, such as a mountain range. The climatic snow line is the point above which snow and ice cover the ground throughout the year. The actual snow line may seasonally be significantly lower.
  • Snow patch is a geomorphological pattern of snow and firn accumulation which lies on the surface longer time than other seasonal snow cover. There are two types to distinguish; seasonal snow patches and perennial snow patches. Seasonal patches usually melt during the late summer but later than rest of the snow. Perennial snow patches are stable for more than two years and also have bigger influence to surroundings.
  • Spring The point at which a stream emerges from an underground course through unconsolidated sediments or through caves. A stream can, especially with caves, flow above ground for part of its course, and underground for part of its course.
  • Spur is a subsidiary summit of a mountain. By definition, spurs have low topographic prominence, as they are lower than their parent summit and are closely connected to them on the same ridgeline.
  • Stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, kill, lick, rill, river syke, bayou, rivulet, streamage, wash, or run.
  • Subalpine refers to the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.
  • Summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a local maximum in elevation. The topographic terms "acme", "apex", "peak", and "zenith" are synonyms.

[edit] T

  • Table, in the sense of a landform, is a hill, flank of a mountain, or mountain, that has a flat top. This landform has numerous names in addition to table.
  • Trim line, also written as trimline, is a clear line on the side of a valley formed by a glacier. The line marks the most recent highest extent of the glacier. The line may be visible due to changes in color to the rock or to changes in vegetation on either side of the line.
  • Tree line or timberline is the edge of the habitat at which trees are capable of growing. Beyond the tree line, they are unable to grow because of inappropriate environmental conditions (usually cold temperatures, insufficient air pressure, or lack of moisture). At the tree line, tree growth is often very stunted, with the last trees forming low, densely matted bushes.

[edit] V

  • Valley a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.

[edit] W

  • Watershed is, in simplest terms, the area of land from which precipitation or surface water flow is drained into a receiving water body. The term is roughly analogous to "drainage basin", and are often used either interchangeably. While primarily describing the geologic/geographic drainage patterns of water, a more holistic view of the word watershed incorporates all the biotic and abiotic communities and processes contained in the drainage basin.
  • Weathering is the breaking down of Earth's rocks, soils and minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, wind, and gravity. In addition, weathering is the effect of atmospheric exposure to man-made structures and materials.

[edit] Also see

[edit] References

  1. Wikipedia List of Landforms [1]
  2. Virtual Geography Department Project University of Wisconsin-Stevens Point [2]
  3. Swisseduc.ch Glaciers On-Line [3]

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