Desert Landforms

Question 1

Name 5 Landforms associated with wind action

Answer 1

Yardangs
Rock Pedestals
Zeugen
Sand Dunes
Barchan Dunes

Question 2

What is a Yardang?

Answer 2

A streamlined hill carved with bedrock or consolidated or semiconsolidated material.

Question 3

How is a Yardang formed?

Answer 3

By dual action of wind abrasion by dust and sand and deflation

Question 4

What do Yardangs become?

Answer 4

Elongated features typically 3x or more time longer than wide

Question 5

How do rock pedestals form?

Answer 5

When sand is lifted by the wind and it erodes at the bottom area of the rock

Question 6

What is another word for rock pedestal?

Answer 6

Mushroom rock

Question 7

What is a Zeugen?

Answer 7

An originally flat area of hard rock overlying soft rock.

Question 8

How do Zeugens form?

Answer 8

Weathering of the exposed hard layer eventually exposes the lower rock to erosion

Question 9

What happens to the soft rock layer of a Zeugen when exposed?

Answer 9

Easily eroded and may end up as isolated rock pedestals.

Question 10

Name 2 differences between Yardangs and Zeugens?

Answer 10

Zeugen has flat top, Yardangs are sloping.
Yardangs can only be caused by wind, Zeugens can be caused by wind and water

Question 11

How do sand dunes form?

Answer 11

With deposition on the leeward side of an obstacle such as a rock and as more sand is deposited, becomes shaped by the wind

Question 12

What are barchan dunes?

Answer 12

Crescent shaped dunes which are often found where there is a dominant wind direction and a limited supply of rock.

Question 13

How do barchan dunes form?

Answer 13

Sand is blown up the gentle downward side then slides down the slip face.

Question 14

Name 5 desert landforms caused by water erosion

Answer 14

Wadi
Mesas
Butte
Inselberg
Salt Flat/Playa Lake

Question 15

What is a wadi?

Answer 15

Dry river valley caused by flash floods

Question 16

How can you identify a wadi?

Answer 16

Often signs of previous high river levels

Question 17

What is an example of a Wadi?

Answer 17

Wadi Degla in Egypt

Question 18

What is a mesa?

Answer 18

When water washes smaller and softer types of rock from top of hill

Question 19

What is a feature of mesas?

Answer 19

Plateau like - flat-topped

Question 20

What is a butte?

Answer 20

Smaller pinnacles of rock, representing an advanced stage of landscape development.
Tall, thin rock

Question 21

What is a inselberg?

Answer 21

More rounded relic features formed from more resistant rocks.

Question 22

What can be some features of inselbergs?

Answer 22

Features of past climates where more weathering has taken place

Question 23

What is playa lake/salt flat?

Answer 23

Water evaporates away leaving salt
No vegetation

Question 24

Name 2 desert landforms caused by deposition

Answer 24

Alluvial Fans
Bajada

Question 25

What is an alluvial fan?

Answer 25

Material carried by a flash flood reaches the valley floor and deposited Fan-shaped

Question 26

What is a bajada?

Answer 26

When several alluvial fans merge together

Question 27

What do bajadas form?

Answer 27

Forms a fringe of sediment at side of mountains

Question 28

What are 3 water processes in deserts?

Answer 28

Exogenous rivers Endoreic/Endorheic rivers Ephemeral Rivers

Question 29

What are exogenous rivers?

Answer 29

Source of river is in mountains/humid regions outside desert regions

Question 30

What are endoreic/endorheic rivers?

Answer 30

Flows into deserts and terminates in deserts (isolated from ocean) Source is in desert

Question 31

What are ephemeral rivers?

Answer 31

Flash floods Flow intermittently after storm events

Question 32

What are ephemeral rivers associated with?

Answer 32

Flashy hydrographs, Wadis

Question 33

When do ephemeral rivers happen?

Answer 33

Once or 2x a year

Question 34

What is deflation?

Answer 34

Wind strips sand from an area leaving pebbles (too large to be moved) Surface is lowered and deflation hollows can form

Question 35

Name 3 wind processes in deserts?

Answer 35

Traction Saltation Suspension

Question 36

What is traction?

Answer 36

Larger particles are rolled or sliding

Question 37

What is saltation?

Answer 37

Bouncing of smaller particles. Wind turbulence causes particles to be lifted and carried.

Question 38

What is suspension?

Answer 38

Finer materials are picked up and carried in suspension

Question 39

What happens to rocks that have been through attrition?

Answer 39

Very rounded rocks