Sand Dunes

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Sand dunes are create by wind deposits. Sand dunes are found in dry environments such as deserts. Deserts work well because they are areas of rapid  heating and cooling which create strong winds. Sand dunes vary in size and shape because of direction of the wind and the amount of sand that is available. There are four types of sand dunes; Barchan, Parabolic, Transverse and Longitudinal (Seif).

Barchan Dunes are the most common and usually come in groups and they can be as large as 100 ft (30m)high and 1000 ft (300m)from tip to tip.

Parabolic Dunes are commonly found on sea coast where winds are moderate. They can be as high as 100 ft in height.

Transverse Dunes are created in high wind areas with large amounts of sand.

Longitudinal (Seif) Dunes form in high and variable winds where small amounts of sand are available. These dunes can reach a height of 300 ft (90m)and can be up to 60 miles (100km)long.

Sand dunes move as wind blows sand up the windward side of the dune over the dune face to the leeward side where it piles up. Dune movement can stabilized or halted with the introduction of vegetation. Vegetation halts or slows dune movement because it covers the sand and the plant's roots acts as an anchor to hold the sand/soil in place.