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AEOLIAN GEOMORPHOLOGY (Places with sediment and low veg cover and low…
AEOLIAN GEOMORPHOLOGY
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WHAT ARE DRYLANDS
Drylands are diverse but all have a moisture deficit where Potential Evapotranspiration (PE) exceeds precipitation.
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Arid, semi-arid, and sub-humid regions of the earth
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WHERE DO DRYLANDS OCCUR
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Hyper arid, arid, semi arid and dry subhumid all seen within N. Africa and across into arab states
Arid, semi - arid and dry subhumid seen within the bottom of Africa
Factors vary over time
At certain locations, flucuations of climate change and dryland extent has been dramatic in past 18ka. There is far few areas of dryland seen presently
History of study
19th and early 20th cent
"extravagant aeolation", seen as prime erosive agent - able to level a landscape to plains
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FEEDBACKS
Bedforms create their own secondary flow regimes, helping to maintain and develop their form, known as dynamic feedback
For example, as wind flows across a dune:
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Famous examples =
The Dust Bowl
Dust storm covered farm land in dust storms in texas and kansas between 35 and 36 example = stratford
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Require reasonable wind-speeds at the surface and freely available sediment ( needs loose or little vegetation)
Common in DRYLANDS AND DESERTS = arid, semi-arid and sub humid regions of the Earth and at coasts
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How it works: Suitable sediment source (sand, silt) + wind energy sufficient to mobilise sediment = aeolian transport
dust, fine sediment entrailed by suspension
sand, coarser sediment entrailed by saltation and creep
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