How and Why Are Sand Dunes Formed?

Vannessa | 01 - 02 - 2021
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What are Sand Dunes & How Are They Formed?

Sand dunes are formed as a result of the deposition of sand carried by the wind. These hill-shaped structures are formed based on the amount of sand, and the direction of the wind in that particular area. 

Sand dunes keep reforming and shifting from time to time because of the blowing winds. These sand structures can grow over 4,000 ft tall depending on how powerful the winds are. Sand dunes are categorized into 5 types depending on the shape. They are

  • Crescent Dunes

Formed in the shape of half moons, crescent dunes are the most common type of dunes found across the globe. When winds of different speeds blowing predominantly in the same direction carry sands of different amounts, crescent shaped dunes are formed. Barchans are crescent shaped dunes one can witness in the arid regions. 

Barchan Dune Is a _______ Shaped Dune.
  • A. Crescent
  • B. Transverse
  • C. Ellipse
  • D. Star
  • Star Dunes

Star dunes are formed basically in areas where the direction in which the wind blows changes a lot. Deposited in the shape of stars, stats reveal that these dunes comprise 8.5% of the world’s sand dunes. Star dunes are also the most irregularly shaped dunes and can be found in the deserts of Africa and Central Asia. 

  • Transverse Dunes

Transverse dunes are sand structures formed like wavy ridges. Barchan dunes can transform into transverse dunes based on the direction and strength of the winds. These dunes are arranged perpendicular to the direction of the wind and are created when large amounts of sand are carried and deposited. 

  • Parabolic Dunes

Looks similar to Barchans but the arms are elongated and resemble U-shaped depressions. Parabolic dunes are commonly present in vegetated sand areas. You can discover these sand dunes in coastal deserts. 

  • Dome Dunes

Unlike the other types of sand dunes, dome dunes are individual structures that are rounded and do not possess slip face. Commonly found along the beaches in arid regions, dome dunes are formed as a result of accumulation of sand behind an obstacle. These may further move to form other types of dunes. 

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