Erosion (of lat.: erodere = abnagen) are the lineful recess of the earth's surface by running waters or glaciers. Wind and sea surf produce planar Erosionserscheinungen.Die wide demolition and smoothing-out of whole land surfaces as Denudation are designated.

Types of the erosion

According to producing Kraft one differentiates:

• River erosion/fluviatile erosion (linear) the drastic activity of running waters (brooks, rivers); the extent of their effect depends on:
  • Quantity of water of running waters
  • Water turbulence and carried material
  • Area morphology (downward gradient)
  • Kind of rock in the underground
  • Climate

By decomposition chemically and physically cut up underground (rock, soil) is away-washed (demolition), which leads in the course of thousands of years to the formation of valleys (valley).

The recess of the flussbettes accompanying with it is called depth erosion, its widening after the side as side erosion.

Since the downward gradient decreases from rivers toward delta, also their ability becomes the materials handling ever smaller. At first still if flints and sand are carried, there is in the muzzle range often only suspended particles. All material, for which the transportation strength is not sufficient any longer, is deposited (sedimentation). The erosion basis is the elevator level, below whose no more erosion forces can work - usually this is the sea level. In the river course lying levels and lakes can represent however local Erosionsbasen with increased sedimentation rate.

By the material removal the river cuts itself steadily further toward to its source into the underground. This procedure is called backwalking erosion and can lead in special cases to the river tapping.

During longer geological periods away it can come in an area to repeated change between erosion and sedimentation features, usually caused by tectonic elevation and lowering procedures of the earth's crust and their effect on the river downward gradient. These changes from sedimentation and erosion phases show up in the remaining sedimentary rock as typical structures, the Erosionsdiskordanzen (Diskordanz).

• Glacier erosion/glaziale erosion (linear)

In areas with according to cold climate (high mountains, polar areas) glacier forms. These move likewise like the water of the rivers, however only with some meters in the year, which leads however to just as clear erosion features. In contrast to the usually V-shaped river valleys the glaciers produce u-shaped valley cross sections, whose typical form suggests also after the melting still its glaziale emergence.

• Abrasion/navy erosion (laminar)

The Brandungswellen of the sea erode the rock of the coastal region. This erosion form attacks the mainland on broad front and leads to breaking fillets as well as smaller and larger cavities in the rock, which collapse with the time. In the coastal process a steep wall, the cliff, on sea level a ever more broadly becoming surface, develops the abrasion platform.

• erosion/wind erosion (laminar)

Wind works above all erosiv if it leads much material (dust, sand) with itself, which gnaws then similarly a sand jet blower at the lining up rock of the underground. This arises preferentially in arid areas (desert) with small vegetation and strong physical decomposition. The features of the wind erosion are summarized under the term Korrasion.

• Soil erosion (laminar)

Reduction of the soil cover soil by wind and water, to its extent dependent on soil type, railing-ran, climate and ground cover.

The effect of the soil erosion is strengthened by human influences (Waldrodung, decrease of the soil-binding vegetation covering, change of the groundwater conditions). Into Hanglagen it can come into consequence to landslides, into levels is reduced the thickness of the fruitful humus layer.

Minors

Rinsing off is planar erosion by rain water.

Efforation is erosion under high water pressure.

See also

Abrasion, washing (geology), ablation, Korrasion, sedimentation, soil erosion, Rodung, consolidation of farmland, Desertifikation, ecological system, Food and Agriculture Organization, Monokultur, irrigation, dune, hedge, Permakultur, quilting, decomposition, Vetiver, dyke

Literature

• Brinkmann, R.: Outline of geology - first volumes - general geology. Enke publishing house Stuttgart ISBN 3-432-80591-8
• Bork, H. - R., H. Bork, C. Dalschow (1998): Landscape development in Central Europe. Gotha
• Judge, G. [Hrsg.] (1998): Soil erosion. - Analysis and balance of an environmental problem. Darmstadt.

Articles in category "Erosion (geological)"

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