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12 Cards in this Set
- Front
- Back
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What are the two types of water-deficient regions?
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1) desert (arid)
2) steppe (semi-arid)- more humid, seperates the desert from the bordering humid climates. |
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Where are deserts located?
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- in regions of subtropics as mid latitudes.
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What is the weathering like in deserts?
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- in dry lands, rock weathering is reduced due to lack of moisture and the scarcity of organic acids.
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what are ephemeral streams?
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- streams that carry out water in response to specific episodes of rainfall.
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What is deflation?
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- the lifting and removal of loose material.
- blowouts can occur. the lower the water table, the larger the blowouts can be since the water holds material down. |
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What factors influence the form and size of dunes?
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- wind direction
- wind velocity - amount of vegetation - availability of sand. |
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What is a barchan dune?
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- crescent shaped dunes with tips pointing downwind.
- little sand availability - no vegetation |
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What is a transverse dune?
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- series of long ridges that are seperated by troughs and oriented in right angles.
- steady wind - sand is plentiful - vegetation is minimal. |
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What is a barchanoid dune?
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- intermediate between barchans and transverse dunes.
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what is a longitudinal dune?
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- series of long sand ridges formed where their is a moderate sand supply and prevailing winds vary but originate from same quadarnt
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what is a parabolic dune?
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- lots of vegetation
- crescent shaped like barchans but points are pointing in opposite way of wind. - along the coast where winds are strong and sand is plentiful |
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what are star dunes?
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- isolated sand hills with ridges extending in all directions.
- wind directions are everywhere. |
