- Stages of wind erosion
- Initiation of movement
- Transport
- Deposit
- Causes
- Weather
- Floor
- Vegetation
- Effects edit
- Types
- Saltation
- Suspension
- Bearing
- References
The wind erosion is the wear or removal rocky soil through the action of winds. It can be caused by deflation, when the wind carries small particles, or by abrasion, when the particles carried by the air wear down the surfaces.
It is more effective in places where vegetation is less: deserts, coasts, estuaries of rivers or places of ancient glaciations, sites generated as a result of the drying of large masses of ancient waters, among others.
Stone Tree
Wind has been a major factor in shaping the Earth's surface as it is known today. It could be said that the water is what gathers the sediments and the wind is in charge of distributing them.
Stages of wind erosion
The mechanism under which wind erosion occurs has three stages:
Initiation of movement
It is the result of overcoming the resistance of the particle to move.
There is a minimum wind speed; From that point on, the wind force is greater than the resistance exerted by the particle through its diameter and density.
Transport
In this stage the quantity of particles and the distance to travel will be defined by the size of the particles, the wind speed and the distance between the parts of the mass that is being transported.
Deposit
It is the moment in which the transportation process stops because the force of gravity is greater than all the forces that keep the particles suspended in the air.
Causes
The factors that come into play in wind erosion are climate, soil and vegetation. The topography usually plays a secondary role, although the length of the area affects the distance traveled by the particles in the soils.
Weather
The influencing climatic actors are precipitation, temperature and wind. Evaporation and perspiration are influenced by temperature and wind. By decreasing humidity, these soil processes facilitate wind erosion.
Floor
Here the texture, structure and density of the particles are usually considered, as well as the apparent density, the moisture content and the coefficient of stringency. Roughness facilitates erosion and crusting decreases roughness.
Vegetation
The height and density of the vegetation are details that are taken into account in the erosive process. The presence of roots and crop residues are effective in cutting wind erosion.
Effects edit
Silt, clay and essential organic matter are blown away by the wind, leaving sandy soil in its wake and consequently more susceptible to future erosion.
It can also result in the transport of some salts, such as sodium or gypsum, to arable areas where, as they settle, they salinize the soils, rendering them unusable.
Likewise, phosphorus can be carried from these areas, causing alterations there. It can also take seeds and insects to areas that do not belong, changing the balance of ecosystems.
This process redistributes the surface particles, creating a skeletonization of the soils and a homogenization of the transported particles.
It is popularly mistakenly believed that desertification is due to lack of rain, especially when it comes to arid and semi-arid systems.
However, the desertification process is unique to wind erosion. The lack of water is responsible for ruining, impoverishing and rendering regions useless, but it does not desert.
Types
Wind erosion can be divided into two types: deflation and abrasion. Deflation occurs when the wind carries loose particles. Abrasion occurs when surfaces are worn by being "scorched" by particles that carry the wind.
Deflation is divided into three subtypes:
Saltation
They are small jumps of the particles suspended on the surface of the ground. The higher the wind force, the more pressure on the particle, generating more height.
Likewise, the higher the height, the more horizontal speed, which produces a greater impact on the surface. The density of the particles, the relief and the wind speed also influence.
This type of movement is usual between particles of 0.05 to 0.5 mm, being those of 0.1 to 0.015 mm more vulnerable.
Saltation is responsible for most of the wind erosion (50-70%), followed by suspension (30-40%) and finally surface creep (5-25%).
Suspension
It happens when the particles removed from the soil remain in the air, because their size and density do not allow them to go down again.
This happens when the wind speed takes the force of gravity out of the equation, causing the particles to be transported long distances in the form of dust clouds. The particles prone to this movement have a diameter of less than 0.1 mm.
Bearing
It applies to the heaviest particles that are dragged on the surface of the ground, driven by the wind or another moving particle.
References
- Lancaster, N. (2005) Aeolian erosion, transport and deposition. Retrieved from Researchgate.net on January 26, 2018.
- Aeolian Landform. Retrieved from Wikipedia.org on January 26, 2018.
- Monitoring aeolian features and processes. Retrieved from Nps.gov on January 26, 2018.
- Vermillion, A. (2004) Aeolian Processes. Retrieved from Cochise.edu on January 26, 2018.