Wind desert landforms

the formation of several wind landforms found in hot arid and semi arid enviroments

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desert pavements

  • deflation ( when the wind picks up and carries material) lowers land surface by removing small particles by the wind.
  • this leaves the larger rocks behind
  • this leaves large areas of bigger material behind which protects the land beneath it from abrasion and further deflation.
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yardangs

  • streamlined wind eroded ridges, that are less than 10m high and more than 100m long.
  • they are aligned with the direction of the prevailing winds
  • people arn't 100% sure on their formation yet, but due to their alignment with the prevailing winds and the abrasion from sand erosion at their bases, this suggests that wind does play some part in their formation.
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ventifacts

  • cobbles and pebbles that have been abraded by wind blown sediment.
  • formed in the direction of the prevailing winds.
  • the windward side is separated from the leeward side by a sharp edge.
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sand dunes

  • accumilations of blown sand which form a mound.
  • sand accumilates when wind speed is reduced due to the increased surface roughness. this means the wind no longer has the momentum to carry the sand and son it is deposited.
  • Sand is then trapped as their is no rocky surfac for the sand to re bound off, so it can't move by saltation. this causes the sand to build up until the wind shapes it into a sand dune
  • when too much sand piles up on the peak of the sand dune, an avalanche occurs on the leeward side, where sand will fall down the slip face.
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Ripples

  • these are small landforms formed by the wind
  • they consist of crests and troughs and develop at right angles to the wind
  • as the wind increaes the wavelengths and heights or the crests increase too.
  • they form with a combination of saltation and creep
  • sand is removed from one crest to another as sand is eroded from the windward side and deposited on the leeward side of the crest.
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sand seas

  • known as ergs in the sahara
  • sand accumilates in areas of reduced wind speed. This could be a small surface depression of a obsticle like a plant
  • plants cause snas shadows to build up around them.
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