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Encyclopedia > Erosion
Severe soil erosion in a wheat field near Washington State University, USA.
Severe soil erosion in a wheat field near Washington State University, USA.

Erosion is the carrying away or displacement of solids (sediment, soil, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms (in the case of bioerosion). We call binary erosion of A by B (which is the structuring element), noted (see Minkowski addition) the set: Categories: | | ... Image File history File links No higher resolution available. ... Image File history File links This is a lossless scalable vector image. ... Download high resolution version (400x604, 82 KB)Image Number K5951-1 Severe soil erosion in a wheat field near Washington State University. ... Download high resolution version (400x604, 82 KB)Image Number K5951-1 Severe soil erosion in a wheat field near Washington State University. ... This article or section cites very few or no references or sources. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland For other uses, see Soil (disambiguation). ... This article is about the geological substance. ... Gravity is a force of attraction that acts between bodies that have mass. ... Bioerosion describes the erosion of hard ocean substrates by living organisms by a number of mechanisms. ...


Erosion is distinguished from weathering, which is the process of chemical or physical breakdown of the minerals in the rocks, although the two processes may be concurrent. Weathering is the decomposition of rocks, soils and their minerals through direct contact with the Earths atmosphere. ...


Erosion is an intrinsic natural process but in many places it is increased by human land use. Poor land use practices include deforestation, overgrazing, unmanaged construction activity and road or building. Land that is used for the production of agricultural crops generally experiences a significant greater rate of erosion than that of land under natural vegetation. This is particularly true if tillage is used, which reduces vegetation cover on the surface of the soil and disturbs both soil structure and plant roots that would otherwise hold the soil in place. However, improved land use practices can limit erosion, using techniques such as terrace-building, conservation tillage practices, and tree planting. Land use is the pattern of construction and activity land is used for. ... This article is about the process of deforestation in the environment. ... // In the dictionary and agriculture, overgrazing is when plants are exposed to grazing for too long, or without sufficient recovery periods. ... Terraced vineyards near Lausanne The Incan terraces at Písac are still used today. ...


A certain amount of erosion is natural and, in fact, healthy for the ecosystem. For example, gravels continuously move downstream in watercourses. Excessive erosion, however, does cause problems, such as receiving water sedimentation, ecosystem damage and outright loss of soil. A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ... Gravel (largest fragment in this photo is about 4 cm) Gravel is rock that is of a certain particle size range. ... This article or section cites very few or no references or sources. ...

Contents

Causes

The rate of erosion tenses on many factors, including the amount and intensity of precipitation, the texture of the soil, the gradient of the slope, ground cover from vegetation, rocks, land use, how much water there is, and possibility of erosion from speed of a stream. The first factor, rain, is the agent for erosion, but the degree of erosion is governed by other factors. In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. ... Soil texture triangle, showing the 12 major textural classes, and particle size scales. ... Aerial view of mixed aspen-spruce forest in Alaska Vegetation is a general term for the plant life of a region; it refers to the ground cover life forms, structure, spatial extent or any other specific botanical or geographic characteristics. ...


The first three factors can remain fairly constant over time. In general, given the same kind of vegetative cover, you expect areas with high-intensity precipitation, sandy or silty soils and steep slopes to be the most erosive. Soils with a greater proportion of clay that receive less intense precipitation and are on gentle slopes tend to erode less. But here, the impact of atmospheric sodium on erodibility of clay should be considered.[1] For other uses, see Sand (disambiguation). ... For other uses, see Silt (disambiguation). ... For other uses, see Clay (disambiguation). ...


The factor that is most subject to change is the amount and type of ground cover. In an undisturbed forest, the mineral soil is protected by a litter layer and an organic layer. These two layers protect the soil by absorbing the impact of rain drops. These layers and the underlaying soil in a forest is porous and highly permeable to rainfall. Typically only the most severe rainfall and large hailstorm events will lead to overland flow in a forest. If the trees are removed by fire or logging, infiltration rates remain high and erosion low to the degree the forest floor remains intact. Severe fires can lead to significantly increased erosion if followed by heavy rainfall. In the case of construction or road building when the litter layer is removed or compacted the susceptibility of the soil to erosion is greatly increased.


Roads are especially likely to cause increased rates of erosion because, in addition to removing ground cover, they can significantly change drainage patterns especially if an embankment has been made to support the road. A road that has a lot of rock and one that is "hydrologically invisible" (that gets the water off the road as quickly as possible, mimicking natural drainage patterns) has the best chance of not causing increased erosion.


Many human activities remove vegetation from an area, making the soil easily eroded. Logging can cause increased erosion rates due to soil compaction, exposure of mineral soil, for example roads and landings. However it is the removal of or compromise to the forest floor not the removal of the canopy that can lead to erosion. This is because rain drops striking tree leaves coalesce with other rain drops creating larger drops. When these larger drops fall (called throughfall) they again may reach terminal velocity and strike the ground with more energy then had they fallen in the open. Terminal velocity of rain drops is reached in about 8 meters. Because forest canopies are usually higher than this, leaf drop can regain terminal velocity. However, the intact forest floor, with its layers of leaf litter and organic matter, absorbs the impact of the rainfall.[2] For other uses, see Log. ... In Hydrology, throughfall is the process which describes how wet leaves shed excess water onto the ground surface. ... For other uses, see Terminal velocity (disambiguation). ...


Heavy grazing can reduce vegetation enough to increase erosion. Changes in the kind of vegetation in an area can also affect erosion rates. Different kinds of vegetation lead to different infiltration rates of rain into the soil. Forested areas have higher infiltration rates, so precipitation will result in less surface runoff, which erodes. Instead much of the water will go in subsurface flows, which are generally less erosive. Leaf litter and low shrubs are an important part of the high infiltration rates of forested systems, the removal of which can increase erosion rates. Leaf litter also shelters the soil from the impact of falling raindrops, which is a significant agent of erosion. Vegetation can also change the speed of surface runoff flows, so grasses and shrubs can also be instrumental in this aspect. Grazing To feed on growing herbage, attached algae, or phytoplankton. ...


One of the main causes of erosive soil loss in the year 2006 is the result of slash and burn treatment of tropical forest. When the total ground surface is stripped of vegetation and then seared of all living organisms, the upper soils are vulnerable to both wind and water erosion. In a number of regions of the earth, entire sectors of a country have been rendered unproductive. For example, on the Madagascar high central plateau, comprising approximately ten percent of that country's land area, virtually the entire landscape is sterile of vegetation, with gully erosive furrows typically in excess of 50 meters deep and one kilometer wide. Shifting cultivation is a farming system which sometimes incorporates the slash and burn method in some regions of the world. This degrades the soil and causes the soil to become less and less fertile. This article is about the agricultural practice of slash and burn. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... This article is about a community of trees. ... For other meanings, see Plateau (disambiguation). ... Aerial view of mixed aspen-spruce forest in Alaska Vegetation is a general term for the plant life of a region; it refers to the ground cover life forms, structure, spatial extent or any other specific botanical or geographic characteristics. ... For methods, see slash and burn Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. ... This article is about the agricultural practice of slash and burn. ...


Effects

Approximately 40% of the world's agricultural land is seriously degraded.[3] According to the UN, an area of fertile soil the size of Ukraine is lost every year because of drought, deforestation and climate change.[4] In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25% of its population by 2025, according to UNU's Ghana-based Institute for Natural Resources in Africa.[5] This article is about the United Nations, for other uses of UN see UN (disambiguation) Official languages English, French, Spanish, Russian, Chinese, Arabic Secretary-General Kofi Annan (since 1997) Established October 24, 1945 Member states 191 Headquarters New York City, NY, USA Official site http://www. ... Fields outside Benambra, Victoria, Australia suffering from drought conditions A drought is an extended period of months or years when a region notes a deficiency in its water supply. ... This article is about the process of deforestation in the environment. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... United Nations University (UNU) is a university established on December 6, 1973 by adoption of resolution 3081 by the United Nations General Assembly, upon the suggestion of U Thant, UN Secretary-General at the time. ...

Bank erosion started by four wheeler all-terrain vehicles, Yauhanna, South Carolina
Bank erosion started by four wheeler all-terrain vehicles, Yauhanna, South Carolina

When land is overused by animal activities (including humans), there can be mechanical erosion and also removal of vegetation leading to erosion. In the case of the animal kingdom, this effect would become material primarily with very large animal herds stampeding such as the Blue Wildebeest on the Serengeti plain. Even in this case there are broader material benefits to the ecosystem, such as continuing the survival of grasslands, that are indigenous to this region. This effect may be viewed as anomalous or a problem only when there is a significant imbalance or overpopulation of one species. Image File history File linksMetadata Download high resolution version (1500x2000, 2869 KB)Bank erosion started by four wheelers (ATVs) Image copyleft: Image taken by me, released under GFDL, Pollinator 01:21, 25 January 2006 (UTC) Permission is granted to copy, distribute and/or modify this document under the terms of... Image File history File linksMetadata Download high resolution version (1500x2000, 2869 KB)Bank erosion started by four wheelers (ATVs) Image copyleft: Image taken by me, released under GFDL, Pollinator 01:21, 25 January 2006 (UTC) Permission is granted to copy, distribute and/or modify this document under the terms of... The ATV is commonly called a quad (quad-bike) in Australia, New Zealand and the United Kingdom. ... A herd of Wildebeest A gaggle of Canada geese For other uses, see Herd (disambiguation). ... Binomial name (Burchell, 1823) The Blue Wildebeest is a large ungulate mammal of the genus Connochaetes which grows to 1. ... This article is about a geographical region; for the National Park see Serengeti National Park A zebra and wildebeests during migration The Serengeti ecosystem is located in north-western Tanzania and extends to south-western Kenya between latitudes 1 and 3 S and longitudes 34 and 36 E. It spans... Map of countries by population density (See List of countries by population density. ...


In the case of human use, the effects are also generally linked to overpopulation. For when large numbers of hikers use trails or extensive off road vehicle use occurs, erosive effects often follow, arising from vegetation removal and furrowing of foot traffic and off road vehicle tires. These effects can also accumulate from a variety of outdoor human activities, again simply arising from too many people using a finite land resource. Map of countries by population density (See List of countries by population density. ...


One of the most serious and long-running water erosion problems worldwide is in the People's Republic of China, on the middle reaches of the Yellow River and the upper reaches of the Yangtze River. From the Yellow River, over 1.6 billion tons of sediment flows into the ocean each year. The sediment originates primarily from water erosion in the Loess Plateau region of the northwest. For other Yellow Rivers, see Yellow River (disambiguation). ... The Yangtze River or Chang Jiang (Simplified Chinese: ; Traditional Chinese: ; Pinyin: ), or Drichu in Tibetan (Tibetan: འབ; Wylie: bri chu) is the longest river in Asia and the third longest in the world, after the Nile in Africa, and the Amazon in South America. ... For other Yellow Rivers, see Yellow River (disambiguation). ... This article or section cites very few or no references or sources. ... This article cites very few or no references or sources. ...


Erosion processes

Gravity erosion

Mass Movement is the down slope movement of rock and sediments, mainly due to the force of gravity. Mass Movement is an important part of the erosional process, as it moves material from higher elevations to lower elevations where other eroding agents such as streams and glaciers can then pick up the material and move it to even lower elevations. Mass-Movement processes are always occurring continuously on all slopes; some mass-movement processes act very slowly; others occur very suddenly, often with disastrous results. Any perceptible down-slope movement of rock or sediment is often referred to in general terms as a landslide. However, landslides can be classified in a much more detailed way that reflects the mechanisms responsible for the movement and the velocity at which the movement occurs. One of the visible topographical manifestations of a very slow form of such activity is a scree slope. Mass wasting, also known as mass movement, is the process by which rock and regolith move downslope mainly due to the pull of gravity. ... Gravity is a force of attraction that acts between bodies that have mass. ... Perito Moreno Glacier Patagonia Argentina Aletsch Glacier, Switzerland Icebergs breaking off glaciers at Cape York, Greenland This article is about the geological formation. ... This article is about geological phenomenon. ... Scree or detritic cone is a term given to broken rock that appears at the bottom of crags, mountain cliffs or valley shoulders. ...


Slumping happens on steep hillsides, occurring along distinct fracture zones, often within materials like clay that, once released, may move quite rapidly downhill. They will often show a spoon-shaped isostatic depression, in which the material has begun to slide downhill. In some cases, the slump is caused by water beneath the slope weakening it. In many cases it is simply the result of poor engineering along highways where it is a regular occurrence. For the anime and manga, see Dr. Slump. ... For other uses, see Clay (disambiguation). ... Glacier Isostatic Depression is the term used by geologists for the sinking of large parts of the earths crust into the asthenosphere. ... For other uses, see Highway (disambiguation). ...


Surface creep is the slow movement of soil and rock debris by gravity which is usually not perceptible except through extended observation. However, the term can also describe the rolling of dislodged soil particles 0.5 to 1.0 mm in diameter by wind along the soil surface.


Water erosion

Nearly perfect sphere in granite, Trégastel, Brittany.
Nearly perfect sphere in granite, Trégastel, Brittany.

Splash erosion is the detachment and airborne movement of small soil particles caused by the impact of raindrops on soil. Image File history File linksMetadata Tregastel_Brittany_France_Curious_Stone. ... Image File history File linksMetadata Tregastel_Brittany_France_Curious_Stone. ... For other uses, see granite (disambiguation). ... Trégastel (Breton Tregastell) is a commune in Côtes-dArmor département, in Brittany, in northwestern France. ... This article is about the historical kingdom, duchy and French province, as well as one of the Celtic nations. ...


Sheet erosion is the detachment of soil particles by raindrop impact and their removal downslope by water flowing overland as a sheet instead of in definite channels or rills. The impact of the raindrop breaks apart the soil aggregate. Particles of clay, silt and sand fill the soil pores and reduce infiltration. After the surface pores are filled with sand, silt or clay, overland surface flow of water begins due to the lowering of infiltration rates. Once the rate of falling rain is faster than infiltration, runoff takes place. There are two stages of sheet erosion. The first is rain splash, in which soil particles are knocked into the air by raindrop impact. In the second stage, the loose particles are moved downslope by broad sheets of rapidly flowing water filled with sediment known as sheetfloods. This stage of sheet erosion is generally produced by cloudbursts, sheetfloods commonly travel short distances and last only for a short time.


Rill erosion refers to the development of small, ephemeral concentrated flow paths, which function as both sediment source and sediment delivery systems for erosion on hillslopes. Generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically on the order of a few centimeters or less and slopes may be quite steep. These conditions constitute a very different hydraulic environment than typically found in channels of streams and rivers. Eroding rills evolve morphologically in time and space. The rill bed surface changes as soil erodes, which in turn alters the hydraulics of the flow. The hydraulics is the driving mechanism for the erosion process, and therefore dynamically changing hydraulic patterns cause continually changing erosional patterns in the rill. Thus, the process of rill evolution involves a feedback loop between flow detachment, hydraulics, and bed form. Flow velocity, depth, width, hydraulic roughness, local bed slope, friction slope, and detachment rate are time and space variable functions of the rill evolutionary process. Superimposed on these interactive processes, the sediment load, or amount of sediment in the flow, has a large influence on soil detachment rates in rills. As sediment load increases, the ability of the flowing water to detach more sediment decreases. A rill is a narrow and shallow incision into soil resulting from erosion by overland flow that has been focused into a thin thread. ... This article or section cites very few or no references or sources. ...


Where precipitation rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence can often cause more erosion than the initial raindrop impact.


Gully erosion results where water flows along a linear depression eroding a trench or gully. This is particularly noticeable in the formation of hollow ways, where, prior to being tarmacked, an old rural road has over many years become significantly lower than the surrounding fields. Gully in El Paso County, Colorado, USA. A gully is a landform created by running water eroding sharply into a hillside. ... Tennysons Lane, a picturesque sunken lane on Blackdown named in memory of the poet. ...


Valley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and headward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat, and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles and boulders can also act erosively as they traverse a surface. This article needs to be wikified. ... The base level of a river or stream is the lowest point to which it can flow, often referred to as the mouth of the river. ... For other uses, see Meander (disambiguation). ... Sea wave polishing pebbles into rounded corners Pebbles For other uses, see Pebble (disambiguation). ... This article is about the large rocks. ...


At extremely high flows, kolks, or vortices are formed by large volumes of rapidly rushing water. Kolks cause extreme local erosion, plucking bedrock and creating pothole-type geographical features called Rock-cut basins. Examples can be seen in the flood regions result from glacial Lake Missoula, which created the channeled scablands in the Columbia Basin region of eastern Washington.[6] A kolk (also known as colc) is an underwater vortex that is created when rapidly rushing water passes underwater obstacle in boundary areas of high shear. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex (pl. ... A Rock-cut basin is the term used for the depression in which a free standing rounded boulder sits within a water filled natural cavity or rock basin in a stream or river; such plucked-bedrock pits are created by Kolks, which are powerful vortices within the water currents. ... Glacial Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. ... DrumHeller Channels The Channeled Scablands are unique geological erosion features in the U.S. state of Washington. ... The Columbia Basin is the large area of Canada and the United States that is drained by the Columbia River. ... For the capital city of the United States, see Washington, D.C.. For other uses, see Washington (disambiguation). ...


Shoreline erosion

See also: Beach evolution
Wave cut platform caused by erosion of cliffs by the sea, at Southerndown in South Wales
Wave cut platform caused by erosion of cliffs by the sea, at Southerndown in South Wales

Shoreline erosion, which occurs on both exposed and sheltered coasts, primarily occurs through the action of currents and waves but sea level (tidal) change can also play a role. This article or section does not adequately cite its references or sources. ... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 376 KB, MIME type: image/jpeg) January 2007. ... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 376 KB, MIME type: image/jpeg) January 2007. ... Wave pounding is the sledge hammer effect of tonnes of water crashing against cliffs. ... Venus Bay is a small tourist and fishing town located on the bay of the same name, on the Eyre Peninsula in South Australia. ... For the song, see South Australia (song). ... Image File history File linksMetadata Download high resolution version (2393x1200, 1737 KB) Summary Wavecut platform, a geological feature caused by the seas erosion of cliffs, seen at Southerndown near Bridgend, South Wales. ... Image File history File linksMetadata Download high resolution version (2393x1200, 1737 KB) Summary Wavecut platform, a geological feature caused by the seas erosion of cliffs, seen at Southerndown near Bridgend, South Wales. ... The formation of a wave cut platform A wave cut platform refers to the narrow flat area often seen at the base of a sea cliff caused by the action of the waves. ... Southerndown is a village close to St Brides Major, Llantwit Major and Ogmore-by-Sea, mostly known for its beach, which is a popular tourist destination during the summer months. ... This article is about the country. ...


Hydraulic action takes place when air in a joint is suddenly compressed by a wave closing the entrance of the joint. This then cracks it. Wave pounding is when the sheer energy of the wave hitting the cliff or rock breaks pieces off. Abrasion or corrasion is caused by waves launching seaload at the cliff. It is the most effective and rapid form of shoreline erosion (not to be confused with corrosion). Corrosion is the dissolving of rock by carbonic acid in sea water. Limestone cliffs are particularly vulnerable to this kind of erosion. Attrition is where particles/seaload carried by the waves are worn down as they hit each other and the cliffs. This then makes the material easier to wash away. The material ends up as shingle and sand. Another significant source of erosion, particularly on carbonate coastlines, is the boring, scraping and grinding of organisms, a process termed bioerosion. You are not currently logged in. ... Wave pounding is the sledge hammer effect of tonnes of water crashing against cliffs. ... Glacially abraded rocks in western Norway near Jostedalsbreen glacier. ... For the hazard, see corrosive. ... Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3. ... For other uses, see Limestone (disambiguation). ... A shingle beach is a beach which is armoured with pebbles or small to medium sized cobbles. ... Bioerosion describes the erosion of hard ocean substrates by living organisms by a number of mechanisms. ...


Sediment is transported along the coast in the direction of the prevailing current (longshore drift). When the upcurrent amount of sediment is less than the amount being carried away, erosion occurs. When the upcurrent amount of sediment is greater, sand or gravel banks will tend to form. These banks may slowly migrate along the coast in the direction of the longshore drift, alternately protecting and exposing parts of the coastline. Where there is a bend in the coastline, quite often a build up of eroded material occurs forming a long narrow bank (a spit). armored beaches and submerged offshore sandbanks may also protect parts of a coastline from erosion. Over the years, as the shoals gradually shift, the erosion may be redirected to attack different parts of the shore. This article or section cites very few or no references or sources. ... Longshore drift (sometimes known as shore drift, LSD or littoral drift) is a geological process by which sediments such as sand or other materials, move along a beach shore. ... Longshore drift (sometimes known as shore drift, LSD or littoral drift) is a geological process by which sediments such as sand or other materials, move along a beach shore. ... A spit is a deposition landform found off coasts. ... Armor, in hydrology and geography is the association of surface pebbles, rocks or boulders with stream beds or beaches. ... For other uses, see Shoal (disambiguation). ...


Ice erosion

Ice erosion is caused by movement of ice, typically as glaciers. Glaciers erode predominantly by two different processes: abrasion/scouring and plucking. In an abrasion process, debris in the basal ice scrapes along the bed, polishing and gouging the underlying rocks, similar to sandpaper on wood. Glaciers can also cause pieces of bedrock to crack off in the process of plucking. These processes, combined with erosion and transport by the water network beneath the glacier, leave moraines, drumlins and glacial erratics in their wake, typically at the terminus or during glacier retreat. Perito Moreno Glacier Patagonia Argentina Aletsch Glacier, Switzerland Icebergs breaking off glaciers at Cape York, Greenland This article is about the geological formation. ... Plucking, in the sense relating to glaciers, is when a glacier erodes away chunks of bedrock to be later deposited as erratics. ... This article is about geological phenomena. ... Drumlin in Cato, New York Drowned drumlin in Clew Bay Drumlin at Withrow Moraine and Jameson Lake Drumlin Field National Natural Landmark A drumlin (Irish droimnín, a little hill ridge) is an elongated whale-shaped hill formed by glacial action. ... A Glacial erratic is a piece of rock carried by glacial ice some distance from the rock outcrop from which it came. ... A view down the Whitechuck Glacier in North Cascades National Park in 1973 The same view as seen in 2006, where this branch of glacier retreated 1. ...


cold weather cause water trapped in tiny rock cracks freezes and expands, breaking the rock into several pieces. This can lead to gravity erosion on steep slopes. The scree which forms at the bottom of a steep mountainside is mostly formed from pieces of rock (soil) broken away by this means. It is a common engineering problem wherever rock cliffs are alongside roads, because morning thaws can drop hazardous rock pieces onto the road. Scree or detritic cone is a term given to broken rock that appears at the bottom of crags, mountain cliffs or valley shoulders. ...


In some places, water seeps into rocks during the daytime, then freezes at night. Ice expands, thus, creating a wedge in the rock. Over time, the repetition in the forming and melting of the ice causes fissures, which eventually breaks the rock down.


Wind erosion

A rock formation in the Altiplano, Bolivia sculpted by wind erosion.
A rock formation in the Altiplano, Bolivia sculpted by wind erosion.
Main article: Aeolian processes

Wind erosion is the result of material movement by the wind. There are two main effects. First, wind causes small particles to be lifted and therefore moved to another region. This is called deflation. Second, these suspended particles may impact on solid objects causing erosion by abrasion (ecological succession). Image File history File links Metadata Size of this preview: 800 × 594 pixelsFull resolution‎ (2,080 × 1,544 pixels, file size: 952 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Metadata Size of this preview: 800 × 594 pixelsFull resolution‎ (2,080 × 1,544 pixels, file size: 952 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Puno, Peru, is one of larger cities of the Altiplano. ... U.S. National Geodetic Survey historical photo showing a survey marker with the effects of wind erosion. ...


Wind erosion generally occurs in areas with little or no vegetation, often in areas where there is insufficient rainfall to support vegetation. An example is the formation of sand dunes, on a beach or in a desert. Windbreaks (such as big trees and bushes) are often planted by farmers to reduce wind erosion. This article is about the sand formations, for other meanings see Dune (disambiguation) Mesquite Flat Dunes in Death Valley National Park In physical geography, a dune is a hill of sand built by eolian (wind-related) processes. ...


Soil Erosion and Climate Change

The consensus of atmospheric scientists is that climate change is occurring, both in terms of global air temperature and precipitation patterns. Warmer atmospheric temperatures associated with greenhouse warming are expected to lead to a more vigorous hydrological cycle, including more extreme rainfall events.[7] In 1998 Karl and Knight reported that from 1910 to 1996 total precipitation over the contiguous U.S. increased, and that 53% of the increase came from the upper 10% of precipitation events (the most intense precipitation).[8] The percent of precipitation coming from days of precipitation in excess of 50 mm has also increased significantly. Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ...


Studies on soil erosion suggest that increased rainfall amounts and intensities will lead to greater rates of erosion. Thus, if rainfall amounts and intensities increase in many parts of the world as expected, erosion will also increase, unless amelioration measures are taken. Soil erosion rates are expected to change in response to changes in climate for a variety of reasons. The most direct is the change in the erosive power of rainfall. Other reasons include: a) changes plant canopy caused by shifts in plant biomass production associated with moisture regime; b) changes in litter cover on the ground caused by changes in both plant residue decomposition rates driven by temperature and moisture dependent soil microbial activity as well as plant biomass production rates; c) changes in soil moisture due to shifting precipitation regimes and evapo-transpiration rates, which changes infiltration and runoff ratios; d) soil erodibility changes due to decrease in soil organic matter concentrations in soils that lead to a soil structure that is more susceptible to erosion and increased runoff due to increased soil surface sealing and crusting; e) a shift of winter precipitation from non-erosive snow to erosive rainfall due to increasing winter temperatures; f) melting of permafrost, which induces an erodible soil state from a previously non-erodible one; and g) shifts in land use made necessary to accommodate new climatic regimes.


Studies by Pruski and Nearing indicated that, other factors such as land use not considered, we can expect approximately a 1.7% change in soil erosion for each 1% change in total precipitation under climate change.[9]


Tectonic effects of erosion

The removal by erosion of large amounts of rock from a particular region, and its deposition elsewhere, can result in a lightening of the load on the lower crust and mantle. This can cause tectonic or isostatic uplift in the region. Research undertaken since the early 1990s suggests that the spatial distribution of erosion at the surface of an orogen can exert a key influence on its growth and its final internal structure (see erosion and tectonics).[10] Geologic provinces of the world (USGS) In geology, a crust is the outermost solid shell of a planet or moon. ... Earth cutaway from core to exosphere. ... A tectonic uplift is a geological process most often caused by plate tectonics which increases elevation. ... Isostasy is a term used in Geology to refer to the state of ice above stasy and is angravitational equilibrium between the Earths lithosphere and asthenosphere such that the tectonic plates float at an elevation which depends on their thickness and density. ... In geology, orogeny is the process of mountain building. ... The interplay between erosion and tectonics has been a matter of debate since the early 1990s. ...


Materials science

In materials science, erosion is the recession of surfaces by repeated localized mechanical trauma as, for example, by suspended abrasive particles within a moving fluid. Erosion can also occur from non-abrasive fluid mixtures. Cavitation is one example. The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... Cavitating propeller model in a water tunnel experiment High speed jet of fluid impact on a fixed surface. ...


In hard particle erosion, the hardness of the impacted material is a large factor in the mechanics of the erosion. A soft material will typically erode fastest from glancing impacts. Harder material will typically erode fastest from perpendicular impacts. Hardness is a correlative factor for erosion resistance, but a higher hardness does not guarantee better resistance. Factors that affect the erosion rate also include impacting particle speed, size, density, hardness, and rotation. Coatings can be applied to retard erosion, but normally can only slow the removal of material. Erosion rate is typically measured as mass of material removed divided by the mass of impacting material. In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation. ... For other uses, see Mechanic (disambiguation). ... A coating is a covering that is applied to an object to protect it or change its appearance. ...


Figurative use

The concept of erosion is commonly employed by analogy to various forms of perceived or real homogenization (i.e. erosion of boundaries), "leveling out", collusion or even the decline of anything from morals to indigenous cultures. It is a common trope of the English language to describe as erosion the gradual, organic mutation of something thought of as distinct, more complex, harder to pronounce or more refined into something indistinct, less complex, easier to pronounce or (disparagingly) less refined. Analogy is both the cognitive process of transferring information from a particular subject (the analogue or source) to another particular subject (the target), and a linguistic expression corresponding to such a process. ... Morality (from the Latin manner, character, proper behavior) has three principal meanings. ... The term indigenous peoples or autochthonous peoples can be used to describe any ethnic group who inhabit the geographic region with which they have the earliest historical connection. ... In linguistics, trope is a rhetorical figure of speech that consists of a play on words, i. ... Sound change or phonetic change is a historical process of language change consisting in the replacement of one speech sound or, more generally, one phonetic feature by another in a given phonological environment. ...


Origin of term

The first known occurrence of the term "erosion" was in the 1541 translation by Robert Copland of Guy de Chauliac's medical text The Questyonary of Cyrurygens. Copland used erosion to describe how ulcers developed in the mouth. By 1774 'erosion' was used outside medical subjects. Oliver Goldsmith employed the term in the more contemporary geological context, in his book Natural History, with the quote Robert Copland (fl. ... A renowned French surgeon of the 14th century, Guy de Chauliac (1300-1368), was the physician for Pope Clement VI. In Avignon, France, he attended to the Pope and survived an infection of the Black Plague. ... Chirurgia magna (complete title: Inventarium sive chirurgia magna), completed in 1363, is a guide of surgery and practical medicine. ... Endoscopic images of a duodenal ulcer. ... For other uses, see Mouth (disambiguation). ... Oliver Goldsmith Oliver Goldsmith (November 10, 1730 or 1728 – April 4, 1774) was an Irish writer and physician known for his novel The Vicar of Wakefield (1766), his pastoral poem The Deserted Village (1770) (written in memory of his brother), and his plays The Good-naturd Man (1768) and...

"Bounds are thus put to the erosion of the earth by water."

See also

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Wikipedia does not have an article with this exact name. ... Image File history File links Wikibooks-logo. ... Image File history File links Wikiquote-logo. ... Image File history File links Wikisource-logo. ... Image File history File links Commons-logo. ... Image File history File links WikiNews-Logo. ... Image File history File links Wikiversity-logo-Snorky. ... Categories: Stub | Geology | Landforms | Alberta geography ... Bioerosion describes the erosion of hard ocean substrates by living organisms by a number of mechanisms. ... The Theory of Biorhexistasy describes climatic conditions necessary for periods of soil formation (pedogenesis) separated by periods of soil erosion. ... Cellular Confinement system example. ... This article is about the process of deforestation in the environment. ... For the labor union vitiation procedure, see NLRB election procedures#Decertification elections. ... Terraces, conservation tillage, and conservation buffers save soil and improve water quality on this Iowa farm. ... Erosion prediction There are dozens of erosion prediction models. ... Subsistence farmers with a Treadle Pump. ... Groundwater sapping is the geomorphic process whereby groundwater exits a bank or hillslope laterally and erodes soil from the slope. ... Riparian strips consist of growth left in or near water courses particularly in clearfelling logging operations. ... The sphericity scale is a measure used by geologists and geographers which measures the sphericity of a stone or particle. ... Runoff flowing into a stormwater drain Surface runoff is water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle[1][2]. Runoff that occurs on surfaces before reaching a channel is also called overland flow. ... TERON is a foundation dedicated to the assessment of tillage related erosion in Europe. ... Vegetation and slope stability are interrelated by the ability of the plant life growing on slopes to both promote and hinder the stability of the slope. ...

Notes

  1. ^ Schmittner Karl-Erich and Pierre, 1999. The impact of atmospheric sodium on erodibility of clay in a coastal Mediterranean region. Environmental Geology 37/3: 195-206.
  2. ^ http://treesearch.fs.fed.us/pubs/14744 Concepts about forests and water Author: Stuart, Gordon W.; Edwards, Pamela J.
  3. ^ Global food crisis looms as climate change and population growth strip fertile land
  4. ^ 2008: The year of global food crisis
  5. ^ Africa may be able to feed only 25% of its population by 2025
  6. ^ Alt, David. Glacial Lake Missoula & its Humongous Floods. Mountain Press Publishing Company. ISBN 0-87842-415-6. 
  7. ^ IPCC. 1995. Second Assessment Synthesis of Scientific-Technical Information relevant to interpreting Article 2 of the UN Framework Convention on Climate Change. Intergovernmental Panel on Climate Change. Geneva, Switzerland. 64 pp.
  8. ^ Karl, T.R. and R. W. Knight. 1998. Secular trend of precipitation amount, frequency, and intensity in the United States. Bulletin of the American Meteorological Society 79:231-242.
  9. ^ Pruski, F. F. and M.A. Nearing. 2002. Runoff and soil loss responses to changes in precipitation: a computer simulation study. Journal of Soil and Water Conservation 57(1), 7-16.
  10. ^ Willett, Sean D., et al, Tectonics, Climate and Landscape Evolution, Geological Society of America Special Paper 398, 2006 ISBN 0-8137-2398-1 PDF of Introduction

Further reading

  • Boardman, John; Poesen, Jean (2006). Soil erosion in Europe. Chichester: Wiley. ISBN 9780470859100. 
  • Montgomery, David R. (2007) Soil erosion and agricultural sustainability PNAS 104: 13268-13272.

Look up Wiley in Wiktionary, the free dictionary. ...

External links


  Results from FactBites:
 
Soil Erosion Site (0 words)
Soil erosion by water, wind and tillage affects both agriculture and the natural environment.
To a large extent this is because soil erosion does not fit neatly under any one heading: it is studied by geomorphologists, agricultural engineers, soil scientists, hydrologists and others; and is of interest to policy-makers, farmers, environmentalists and many other individuals and groups.
It aims to be the definitive internet source for those wishing to find out more about soil erosion.
Soil Erosion (773 words)
Wind and water are the main agents of soil erosion.
POLITICS, ECONOMICS AND SOIL EROSION To understand soil erosion we must be aware of the political and economic factors affecting land users.
On commercial farm lands, overstocking, mono-cropping, and the ploughing of marginal lands unsuitable for cultivation has led to soil erosion and desertification.
  More results at FactBites »

 
 

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