EROSION

It is defined as the action of gnawing, spend, causes a loss of substance of the relief and produces a vacuum, a volume decrease. In this work of sculpture is given a hidden name that is sometimes known, the gliptogenesis.

Erosion occurs when water, ice or wind drag the ground or weathered rock. The soft rock is more likely to be fragmented and pulled hard rock.

When erosion occurs suddenly, can be very dangerous. Avalanches and landslides and mud are examples of mass movements: that is, sudden movements, downhill, a large amount of soil, rock and water.

The removal and displacement of material worn assume a transport, which is the second phase of the process of erosion. The gravity along a slope, wind, etc say this shift.

And after a wear or material loss and subsequent transport of the same lead to an accumulation which is the last phase of this process called erosion.


THE EROSION IS CAUSED BY THE WIND, BY THE WATER AND ICE

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http://geography.about.com/od/physicalgeography/a/erosion.htm
http://en.wikipedia.org/wiki/Erosion
http://www.youtube.com/watch?v=eVEwgh4dExg&feature=related

GLACIAL EROSION

Erosive glaciers are of great importance that, in the past, shaped much of the landscape we now know in middle and high latitudes around the globe.

The huge masses of ice moving slowly due to the gravity term lead to wear a relentless task of the land on that slide, which can be easily observed in regions where glaciers have disappeared. The ice is able to cut or tear huge rocks that other erosive agents could not.

AVALANCHES

A different form of erosion of glaciers, but also caused by the accumulation of water in solid form, are avalanches. An avalanche is the detachment of large masses of ice and snow that falls from the peaks to the valleys. In its wake, an avalanche dragged the vegetation, leaving a trail of bare ground where it can work more easily erosion.

Landslides occur when heavy snow accumulates in a zone of high slope, especially when another layer is deposited on a different consistency that can serve as a gliding surface, remaining in an unstable equilibrium.

The trigger of the landslide may have various origins. Can occur spontaneously when the very weight of a layer exceeds the frictional force that kept at rest. Landslides also occur at the time of thawing, decreasing the holding power. Even with the passage of skiers or vibrations of any kind.
A small mass of snow starts falling. By supporting your weight on other makes too loose. Thus, as it descends new masses are added until it can come to acquire a large volume. It is therefore one of the few forms of erosion in a violent act in a short time.

WIND EROSION

The wind itself is not strong enough to produce effects of weathering. What you can do is carry particles, when they hit the ground, which are worn. This erosion is usually slow and to occur, the territory should be naked, as the vegetation reduces or nullifies the effect.

Wind erosion occurs because, in arid areas such as deserts and high mountains. They have also another essential characteristic: large temperature differences. This causes the rock to break off and wind erosion can act more effectively.

Corrosion is the abrasion suffered by the rocks being rubbed by the impacts of sand particles that are transported by wind. When these particles strike the rocks undergo a transformation in turn, taking a rounded appearance. When the wind loses strength transported material is deposited gradually, which usually leads to the accumulation of particles of similar size and weigth

The wind erosion agent

Wind is an effective erosion agent capable of starting, lifting and carrying particles, however, eroding their ability to compact and hard rocks is limited

If the surface is made of hard rock, the wind is unable to cause significant changes since the cohesive force of the material exceeds the force exerted by the wind. Only in those places where the exposed surface of mineral particles containing loose or loosely cohesive, wind can express their full potential for erosion and transport. Speed determines the ability of wind to erode and drag particles, but also influences the nature of the material, topography, the protective efficacy of vegetation, etc.,

In the phenomenon of wind erosion, is determining the surface acted upon by the wind. Its alteration is not limited to points or restricted areas as with water erosion, wind action is exerted on the entire surface. In large spaces, often produces erosion excavated shallow depressions called pits, basins or depressions of deflation. They originate in areas more or less flat and devoid of vegetation where the soil is exposed to wind action. Fine particles (clay and silt) are lifted by vertical currents which exceed the settling velocities, the powder is diffused in the atmosphere at altitudes ranging from few meters to several thousand. The height depends on the intensity of turbulence of the wind, its duration and size of the particles. As a result, there may be a thick cloud, called a dust storm.

EROSION BY WATER

Inland waters are an agent of erosion of the first magnitude. In the form of rivers that flow on the surface or underground streams, the water wears away the material through which it passes there and drag the remains into the ocean, leaving deposited in various places, forming new soil and, ultimately, modeling landscape.

Water creates waterfalls, gorges, meanders and deltas. Sometimes certain areas flooded, more or less extensive, the territory. Life has developed more prolific, always on the margins of the rivers.



THE EROSIVE ACTION OF RIVERS


The erosion due to flowing water follows the same stages that naturally divides the course of a river. There is a first stage where mechanical erosion by water and materials that drag is very intense in the upper reaches of river. In the second stage, transport, mechanical erosion is s


This takes place in the middle. Finally, during deposition under predominantly transported materials, the mechanical action is reduced greatly and acts almost exclusively chemical erosion.

The erosion of a river due to water power. It is able to boot chunks of rock, being washed away, act like a hammer on the bed of the river, releasing new pieces. As the channel is not regular, they usually produce eddies that carry sand and gravel, polishing the bottom of the river, creating cavities.

Other times, the slope causes water to form high falls, cascades and waterfalls, some of which reach up to 1000 meters. The drop zone upstream gradually recedes as it wears. In other cases, when the course is great odds, the water "looks" the most frágines, the wear and form gorges or canyons.

In calcareous soils is often the emergence of underground caves erosion caused by water chemistry, which transforms the insoluble carbonate to bicarbonate soluble.

FLOODS

During seasons of heavy rains or melting occurs, the flow of a river can increase that does not fit well within their banks. Then the water overflows the banks. This phenomenon often occurs gradually, but others do it violently, causing a major erosion in the entire territory.

Meandering

The result of the erosion is more or less fine material by the flowing water along the river course. In the middle begin to be deposited when the force of the current is not able to keep these particles in suspension.

But after the erosive force acts on these deposits and wears more for the area where the water velocity is increased, while new materials deposited where it is weakest. The end result is a sinusoidal form deposits called meanders. With time and floods, the river can return to find their way in a straight line, leaving gaps in their margins crescent-shaped.

Deltas
The end of the fluvial erosion process takes place at the mouth of the river, although in some cases the current force is capable of further erosion of the bottom of the continental shelf and form a submarine valley.

In many cases, especially in large rivers with a lot of erosion, the finest materials are deposited at the mouth forming a delta .. The deltas are therefore extensive sedimentary in which there is a constant balance between the destructive force of the flow and deposition of new materials.