Wind and Its Functions
About one-third of the Earth's land area is arid, semi-arid and desert. Lack of humidity and vegetation is often seen in these regions. Due to lack of humidity and vegetation, the soil particles here remain loose. Wind is an important contributor to denudation in these areas. Winds do three types of work in these areas, due to which different types of wind formed topographies are formed.
Works of Wind
Winds perform three types of functions in arid and semi-arid areas, which are as follows –
- Deflation
- Abrasion or Corrasion
- Attrition
1. Deflation
In this, the unorganized particles of the soil are blown away by the wind, as a result of which the trough is formed.
Lag Deposits and Marukuttim (Desert Pavement)
When the wind carries away the small particles of the soil by the process of ablation, then the bigger particles are left behind. These large particles are called Lag Deposits and the surfaces formed as a result of wind erosion are called Marukuttim (Desert Pavement).
2. Abrasion or Corrasion
In this, the wind wears the rocks and makes them smooth by the action of friction. Various shapes are formed in the rocks by this process.
3. Attrition
In this, the sand particles flying with the wind collide with each other and form small and fine particles.
How Addiction Affects The Body ?
A. Landforms Formed By Wind Erosion
In the process of erosion, particles of soil or sand are blown away by the wind and reach from one place to another, due to which different types of wind-made topographies or structures are formed. These formations include Blow Outs, Mushroom or Gara, Dreikanter, Stone Lattice, Yardang, Jugen. Zeugen), Domed Mound or Inselberg, Demoiselle, Wind Gap, etc., wind formed topographies are formed.
- Blow Outs
- Mushroom or Gara
- Yardang
- Zeugen
- Dreikanter
- Stone Lattice
- Demoiselle
1. Blow Outs
In arid and semi-arid desert areas, small depressions or pits are formed due to blowing of the sand on the surface due to the ablation action of the wind. These troughs later grow to a larger size. These troughs are called blow outs. Very long and deep wind troughs are found in Mongolia, which are called Pangkiang there.
2. Mushroom or Gara
When the lower part of a rock is cut due to wind erosion and the upper part remains like an umbrella due to being hard, then this type of topography is called Mushroom or Gara. Their structure looks like an umbrella or a mushroom.
3. Yardang
When soft and hard rocks are in a parallel sequence, the soft rocks are cut away due to wind erosion while the hard rocks remain standing. In this way, due to erosion, a groove-shaped pit is formed in the middle of the hard rocks, which is called Yardang.
4. Zeugen
Where soft and hard rocks lie in a horizontal sequence, due to dew filling in the crevices of these rocks and the fall of temperature in the night, erosion of soft rocks starts, due to which a medicine-like shape is formed. This medicinal shape is called Zeugen. In this, the hard rocky part looks like a cap of a drug.
5. Dreikanter
When the sand-laden air collides with the hard rocks lying on the land, it wears them down making them smooth and triangular. These triangular pieces of stone are called Dreikanter.
6. Stone Lattice
When such rocks come in the path of fast-moving air, which are full of diversity, that is, hard, soft and other types are present together in that rock, then the air cuts the soft parts of this rock and starts flowing across it. | In this way, due to the flow of air, the rocks become perforated and appear like a lattice, which is called Stone Lattice.
7. Demoiselle
When hard rock is overlain on loose and soft rock, then the hard rock provides protection to it. But the rocks adjacent to it continue to be eroded. As a result of erosion, the hard rock remains in the form of a pillar, which is called Demoiselle.
Some Important ShapesFormed as a Result of Weathering and Erosion
B. Landforms Formed By The Deposition Action Of Wind
Due to the deposition of eroded materials in arid and semi-arid desert areas, sand dunes, sand levees or whalebacks, loess, barkhans, playa etc. are formed by wind.
- Sand Dunes
- Longitudinal Sand Dune
- Transverse Sand Dune
- Loess
- Playa
- Domed Mound or Inselberg
- Bolson
- Bajada or Bahada
1. Sand Dunes
As a result of the deposition process of wind, sand dunes are formed, which are called sand dunes. These mounds are not permanent. Their transfer takes place in the direction of the wind. These are of two types. Under these, different types of Stupas like – Lunet, Whale Back Stupa, Tara Stupa, Seef etc. are found at different places.
- Longitudinal Sand Dune
- Transverse Sand Dune
i. Longitudinal Sand Dune
This sand stupa is made parallel to the direction of the wind and there are steep slopes on both sides of it. In Sahara it is called Sief.
ii. Transverse Sand Dune
This sand stupa is made perpendicular to the direction of the wind. In the direction from which the wind comes, its gradient is slow and convex in that direction and on the other side the gradient is sharp and concave. This type of sand stupa is found in abundance in Turkey. There they are called Barkhans. Its structure is similar to half moon.
2. Loess
Loess is formed as a result of the deposition of fine dust particles blown by the wind in areas outside the desert region. It lacks layers. This soil is very fertile. Loess plains are found in northwestern part of China, Ukraine, Mississippi Valley, Pampas region of Argentina and New Zealand. The loess plains of China were formed by the deposition of dust particles blown from the Gobi Desert. Their color is yellow due to oxidation, while the loess plains of Europe and New Zealand are formed as a result of the deposition of wind blown sediments from glacial deposits.
3. Playa
The inflowing rivers of the desert areas form a temporary lake after rain, which is called Playa Lake. These lakes dry up after the rainy season. The surface of these lakes made of alluvium is called playa. When the amount of salt increases in Playa, it is called Salina. Celina is called Sebcha in Sahara, Kenire in Iran, Shotts in Mexico and Takyre in Transcaucasia.
4. Domed Mound or Inselberg
In an arid or semi-desert area, when the rocky part is flattened by breaking or cutting by wind erosion and the hard rocks emerge here and there in the form of standing mounds, then these hill topography is known as domed mound or Inselberg. And the hard flat surface is called Pediplain. Inselberg is also known as Bornhardt.
5. Bolson
In desert areas, the lowland or basin surrounded by mountains is called Bolson.
6. Bajada or Bahada
These are alluvial fans formed by the deposition of debris obtained from the erosion of mountains in the desert areas, which are called Bajada or Bahada.
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