Wind-blown sediments are deposite as a result of a significant reduction in wind speed and obstruction caused by bushes, forests, marshes and swamps, lakes, large river walls, and so on. Sand is deposite on both the windward and leeward sides of fixed obstacles. The depositional landforms of the wind such as barchan, seif, parabolic, transverse dunes, longitudinal dunes, etc.
Sand dunes
- Deserts that are dry and hot are ideal for the creation of sand dunes.
- Dunes classification includes Barchans, Seif dunes, and others, based on their shape and position on the landscape.
- People can see the barchan as a characteristic desert landform all over the world.
- Sand dunes are heaps or mounds of sand found in deserts. Generally their heights vary from a few metres to 20 metres but in some cases dunes are several hundred metres high and 5 to 6 km long.
Some of the forms are below :
Longitudinal dunes
- Formed parallel to the wind movement. The windward slope of the dune is gentle whereas the leeward side is steep.
- These dunes are commonly found at the heart of trade-wind deserts like the Sahara, Australian, Libyan, South African and Thar deserts.
Transverse dunes
- Dunes deposited perpendicular (transverse) to the prevailing wind direction.
Barchans
- Crescent shaped dunes. The windward side is convex whereas the leeward side is concave and steep.
Parabolic dunes
- They are U-shaped and are much longer and narrower than barchans.
Star dunes
- Have a high central peak, radically extending three or more arms.
Loess
- Wind-transported silt that has settled out from dust storms over many thousands of years has covered huge regions of the earth’s surface in numerous parts of the world, including the United States.
- Loess are types of depositions.
- In some parts of the world, windblown dust and silt blanket the land. This layer of fine, mineral-rich material is called loess.
- Northern China, the Great Plains of North America, central Europe, and parts of Russia and Kazakhstan contain extensive loess deposits.
- The thickest loess deposits are near the Missouri River in the U.S. state of Iowa and along the Yellow River in China.
- Loess accumulates, or builds up, at the edges of deserts. For example, as wind blows across the Gobi, a desert in Asia, it picks up and carries fine particles. These particles include sand crystals made of quartz or mica. It may also contain organic material, such as the dusty remains of skeletons from desert animals.
- Loess often develops into extremely fertile agricultural soil. It is full of minerals and drains water very well. It is easily tilled, or broken up, for planting seeds.
- Loess usually erodes very slowly – Chinese farmers have been working the loess around the Yellow River for more than a thousand years.
Depositional Landforms by Wind Blows,Depositional Landforms by Wind Blows
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