003 - Hot, Arid Landforms

Geographic Knowledge and Understanding

Hot, arid landscape features, including dunes, wadis, rock pedestals, mesas and buttes.

Key Concepts

The processes of erosion, transport and deposition are necessary for the creation of unique desert landforms.

Aims

To be able to describe the arid environment processes of erosion, transport and deposition.

To be able to explain how arid processes contribute to the creation of landform features including dunes, wadis, rock pedestals, mesas and buttes.

Key Terminology

  • Regolith
  • Insolation weathering - granular weathering, exfoliation, block disintegration
  • Deflation
  • Corrasion
  • Attrition
  • Aeolian Transportation - suspension, saltation, creep
  • Sand dunes
  • Wadis
  • Rock Pedestals
  • Mesa
  • Buttes

We will be finding out what the landforms are above along with the processes that created them during the course of the lesson. If you are still unsure of what they are use the useful links below to define them.

Useful Links

Activity One - Processes

While deserts are generally dry precipitation does fall in these regions and the rainfall can be dramatic. As you know from studying the Freshwater unit water is a key cause of weathering and erosion. Wind or aeolian forces also create a number of the dramatic landscapes that can be found in deserts. Answer the following questions using the text book recommended below:

  1. What is regolith?
  2. Describe the process of insolation weathering also known as onion-skin weathering. Remember to discuss the different types; granular disintegration (minerals expanding), exfoliation (peeling) and block disintegration (jointed rock).
  3. How does salt weathering occur?
  4. Remind yourselves how freeze-thaw occurs. Write a short description of the process.
  5. What forms of chemical weathering take place in a desert?
  6. Describe the processes of deflation, corrasion and attrition.
  7. Draw a fully annotated diagram to show aeolian transportation. Remember to include the words suspension, saltation and creep. There is an image below that will also help you.
  8. Why does aeolian deposition take place?
  9. While water is scarce in deserts when it does rain the processes occurring can be powerful?

Useful Resources

Dry Regions - The geology of deserts

'Arid Environments' text book by Cole pages 34-44

Taken From: https://images-na.ssl-images-amazon.com/images/I/51ftUaAsweL._SX358_BO1,204,203,200_.jpg

Image One - Transportation by Wind

Taken From: http://www.revision.co.zw/wp-content/uploads/2015/06/wind_transport-min-600x427.jpg

Activity Two - Landforms created by wind

Aeolian Landforms

As you watch the youtube clip below answer the following questions:

  1. Does water or wind create more change in a desert?
  2. What is sand made up of?
  3. Describe what a sand dune is and how it is formed (you may also need to use the text book to help you with this).
  4. What factors does a sand dune depend on for its development?
  5. What is a barchan sand dune? How does it form?
  6. What is a star dune?
  7. What is a linear dune and how is if formed?

Now you have watched the youtube clip you will need to 'flesh out' what landforms are created by wind in a desert, what they look like and how they are formed. The list below are the landforms you should focus on:

                    • Desert Pavements
                    • Zeugen
                    • Barchan or Crescent sand dune
                    • Linear dunes

Useful Resources

For images - geogalot

Desert Landforms Created by Wind

'Arid Environments' text book by Cole pages 49-57

Taken From: https://images-na.ssl-images-amazon.com/images/I/51ftUaAsweL._SX358_BO1,204,203,200_.jpg

Activity Three - Landforms created by water

Create a guide to desert landforms created by water, this could be in the form of an i-spy guide where you have a labelled diagram along with an explanation of how the landform is formed. You need to make sure you have an annotated diagram of each landform, describe what it looks like and also explain how they are formed. Those of you that went to Morocco can use and share with the group the photographs that you took. The landforms you need to focus on are:

                      • Wadis
                      • Canyons
                      • Mesa, Butte, Spire
                      • Alluvial fan

Image Two - Erosional Landforms

Taken From: https://i1.wp.com/www.pmfias.com/wp-content/uploads/2015/12/desert-landforms-bajada-palaya-butte-mesa-butte.jpg?resize=980%2C651

Useful Resources

Pdf - Desert Landforms

'Arid Environments' text book by Cole pages 59-69

Taken From: https://images-na.ssl-images-amazon.com/images/I/51ftUaAsweL._SX358_BO1,204,203,200_.jpg

Activity Four - 360 VR - Identify

Using the roundme.com app on your phones search for the Western Desert of Egypt. Using the different 360 degree images identify as many of the landforms you have described and explained above.