Wind Processes

Question 0

Quickly name the landforms created by wind erosion.

Answer 0

1. Rock pedestals.
2. Desert pavement
3. Zeugens
4. Yardangs
5. Deflation hollows

Question 1

Name the Processes of wind erosion and define them.

Answer 1

1. Abrasion - when wind picks up articles of sand and scours rock sur-faces. Sand can only be lifted up 1m. when sand and dust blows agains rocks, it may polish the rock resulting in a shiny surface called desert varnish.
2. Attrition - When sand particles carried by wind grind each other.
3. Deflation - When wind blows materials away from an area, leaving a hollow behind. can cause an oasis in a desert.
4. Wind Deposition - Leads to formations like sand dunes and loess.

Question 2

What is a rock pedestal and how is it formed?

Answer 2

• They are created by abrasion.
• abrasion is limited to othe area close to the ground.
• large rocks are eroded at their bases and eventually forms rock pedestals.
• these rocks consist of hard and soft layers.
• the wind swirls and erodes it from all sides.
• Softer layers are eroded faster.
• gives odd shapes to the rock pedestals.

Question 3

What is desert pavement?

Answer 3

• when wind continuously removes fine materials until only large rocks, stones and pebbles remain.

Question 4

What are Zeugens and how do they forms?

Answer 4

• they from where there are horizontal layers of hard and soft rock.
• weathering opens cracks in the rocks.
• wind abrasion widens the cracks.
• the hard rock wil form ridges while the soft rock is eroded away leaving furrows.
• it can be 3-36 m height.

Question 5

Describe what is Yardangs.

Answer 5

• Here hard and soft rock layers lies vertically.
• They also lie parrallel to the wind.
• Softer material is removed by erosion to form furrows.
• hard rock remains as ridges
• can not be more that 15m in hight.

Question 6

What is a Deflation hollow?

Answer 6

• It is when the process deflation occur.
• can erode deep enough to reach water.
• can become an oasis.

Question 7

Name and describe the processes of wind transportation.

Answer 7

1. Suspention - very fine dust are carried in the air for long distances.
2. Saltation - Rough, grainy sand which bounces along the ground.
3. Surface creep - Larger particle that creeps along the surface.

Question 8

Describe what is a barchan dune.

Answer 8

• they are cescent-shaped dunes and start to form when sand colects around asmall rock or piece of vegetation.
• Horns of crescent-shaped dunes alway point away from the wind.
• forms when a limited supply of san and wind blows from one direction for long periods.
• gentle slope facing the wind and a steep slope on the other side.
• they can migrate 20m a year.

Question 9

What is a Transverse dune?

Answer 9

• develope where there are more sand and wind blows constantly from one side.
• resenbles a row of high barchan dunes that have joined- to gether.
• migrates downwind.
• Very slowly.

Question 10

What is Longitudinal dunes?

Answer 10

• they lie parallel to the wind direction.
• can be 160km long and 100 to 200 m high.
• common in the Sahara

Question 11

Describe Star dunes.

Answer 11

• Found where wind direction changes constantly.

- looks like a star.