Roll of wind and water in shaping landforms

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  • Created by: hamishc
  • Created on: 11-04-16 18:40
Role of wind deflation erosion
Wind removes unconsolidated material (creating deflation hollows, salt pans and desert pavements and yardangs)
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Role of wind corrasion erosion
Sand carried in wind abrades rock surface (producing sculptured rocks and ventifacts).
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Role of wind attrition erosion
Sand grains collide with each other and become smaller.
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What are deflation hollows?
large enclosed depressions
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What are salt pans?
Flat areas encrusting with salt
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What are desert pavements?
Surface of stones resting on a finer material such as silt or clay
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What are ventifacts?
Wind polished stones which look like brazil-nuts, they are a few centimetres in size.
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What are yardangs?
Yardangs are formed when resistant rocks like limestone are uncovered as less resistant material around them is removed via wind erosion. They are appear as steep crested, linear ridges of rock parallel to prevailing winds.
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What is suspension, saltation and surface creep?
suspension is when small particles are carried within wind, saltation is when medium particles hop along the ground, surface creep is when larger particles roll or are pushed along the ground.
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How do the previous processes produce landforms?
Wind picks up sand from near lakes and seas and it is carried huge distances into deserts where it is deposited as sand dunes due to obstacles like rocks which cause friction.
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Name 2 ways sand is deposited
Sand seas, sand sheets, star dunes.
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Difference between fixed dunes and free dunes
Fixed dunes form around obstacles such as rocks, whilst free dunes form where there is no obstruction
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Difference between transverse and linear dunes
Transverse moves normal to wind flow whilst linear dunes are parallel to wind flow.
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Name a case study on this topic
Namid Desert, Namibia (Contains sand seas at 75% near walvis bay, yardangs in the south, and ventifacts in dolerite.
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How does water erosion occur in arid areas?
Heavy convectional rainfall is forced to run across surface rather than infiltrate due to little vegetation and baked impermeable crust..
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What landforms are created by water erosion?
Wadis (dry river valley with steep sides and wide floor, caused when seasonal rains bring ephemeral rivers), canyons (a gorge with a deep narrow channel bounded by resistant rock, the bottom is inhabited by an exogenous river).
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What are ephemeral rivers?
A temporary river that flows intermittently or seasonally.
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What are exogenous rivers?
A permanent river which derives its water from beyond the desert margin.
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How does water deposition occur in arid areas?
Lakes form in flat areas (due to surface run-off, precipitation, and groundwater), this water evaporates leaving a saline crust
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What landforms form due to water deposition?
Salt pans (when lakes dry out, salt weathering loosens material on the floor of the pan, which is eroded by the wind), Sabkhas (type of salt pan fringing coastal areas such as the Arabian sea).
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Other cards in this set

Card 2

Front

Role of wind corrasion erosion

Back

Sand carried in wind abrades rock surface (producing sculptured rocks and ventifacts).

Card 3

Front

Role of wind attrition erosion

Back

Preview of the front of card 3

Card 4

Front

What are deflation hollows?

Back

Preview of the front of card 4

Card 5

Front

What are salt pans?

Back

Preview of the front of card 5
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