003 - Hot, Arid
Geographic Knowledge and Understanding
Hot, arid landscape features, including dunes, wadis, rock pedestals, mesas and buttes.
The processes of erosion, transport and deposition are necessary for the creation of unique desert landforms.
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.
Insolation weathering - granular weathering, exfoliation, block disintegration
Aeolian Transportation - suspension, saltation, creep
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.
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.
What is regolith?
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).
How does salt weathering occur?
Remind yourselves how freeze-thaw occurs. Write a short description of the process.
What forms of chemical weathering take place in a desert?
Describe the processes of deflation, corrasion and attrition.
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.
Why does aeolian deposition take place?
While water is scarce in deserts when it does rain the processes occurring can be powerful?
Activity Two - Landforms created by wind
We are initially going to focus on landforms that are created by wind. The fancy word for this is aeolian forces. As you watch the youtube clip below answer the following questions.
Does water or wind create more change in a desert?
What is sand made up of?
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).
What factors does a sand dune depend on for its development?
What is a barchan sand dune? How does it form?
What is a star dune?
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:
Zeugen/Rock Pedestal/Mushroom Rock (often volcanic)
Barchan or Crescent sand dune
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:
Mesa, Butte, Spire
Activity Four - 360 VR - Identify
Using the different 360 degree images identify as many of the landforms you have described and explained above.