001 - Glacial processes

and landforms

Geographic Knowledge and Understanding

Glacial processes of erosion, transport and deposition, and landscape features in glaciated areas, including cirques/corries, lakes, pyramidal peaks/horns, arêtes, glacial troughs; lateral, medial and terminal moraine and erratics.

Key Concepts

The processes of erosion, transport and deposition are necessary for the creation of glacial landscapes.

Aims

  • To be able to describe the glacial processes of erosion, transport and deposition.

  • To be able to explain how glacial processes contribute to the creation of landscape features including cirques, glacial lakes, pyramidal peaks, arêtes, glacial troughs; lateral, medial and terminal moraine and erratics.

Key Terminology

            • Weathering

            • Erosion

            • Deposition

            • Snout

            • Supraglacial debris

            • Englacial debris

            • Subglacial debris

            • Frost Shattering

            • Abrasion

            • Plucking

            • Bergschrund

            • Rotational Movement

We will be using a lot of new terms throughout the course of this lesson, above are just a few to get started. Define the terms above using the useful link below.


Useful Link

Activity One - Glacial Movement

During the previous lesson we began to look at how glaciers are actually rivers of ice, we now need to look at how they actually move. The movement of the ice is essential for creating a number of the impressive landforms. Answer the following questions:


      1. Define the word internal deformation.

      2. Define the word basal sliding.

      3. Write a definition of subglacial deformation.

      4. What is a glacial surge?

Useful Resources


Cliffsnotes - Glacial Movement (you may need to search for glacial movement)

National Park Service - Why do they move?

'Glaciation and Periglaciation' Advanced Topic Master by Jane Knight pages 18-27

Activity Two - Processes

Before we look at the specific erosional landforms you need to understand the processes behind the formation them. We will start with the basics and look at the differences between weathering and erosion. Watch the youtube clip below and write down the difference between weathering and erosion.

Now we can look at the specific forms of weathering and erosion that occur within a glacial environment. With the aid of diagrams explain how the following processes work (the first one is weathering and the others are forms of erosion):


                1. Frost shattering (or freeze-thaw weathering)

                2. Abrasion - What factors impact the rate of abrasion? What evidence is there on rocks to suggest that abrasion has taken place in an area?

                3. Plucking

                4. Rotational movement

                5. What is regolith?

Useful Resources

Activity Three - Erosional Landforms

We are now going to look at a number of landforms that can be found in a predominately Alpine glacial environment. If you have skied, snowboarded, snow shoed of cross country skied you have seen these features without really knowing what they are.


  1. Copy and complete the table below. Remember you need to be able to draw and annotate how landforms are created as it is a geographical skill they may ask you to do in the exam.


Erosional Glacial Landform Guide

Useful Resources

Taken From: https://cdn.shopify.com/s/files/1/1975/4441/products/bed31aa0-27fa-45d8-bda8-2490fa23e524.png?v=1501766254

Our Planet's Extreme Environments by Codrington

Pages 41-45

Taken From: https://images-na.ssl-images-amazon.com/images/I/51iEP8gWFJL._SX353_BO1,204,203,200_.jpg

Glaciation and Periglaciation by Knight

Pages 33-42

Great Videos on cirques, aretes, pyramidal peaks and U-shaped Valleys

Activity Four - Depositional Landforms

You are now going to look at landforms that are created by glacial deposition. These are not always as easy to see as the erosional processes but they are there if you look closely.


      1. What is deposition?

      2. Remind yourselves what supra, en and subglacial transportation is.

      3. Why do glaciers deposit their material?

      4. How does material get into the middle of glaciers?

      5. Copy and complete the table below. Remember to annotate your diagrams.

Depositional Landform Guide

Useful Resources

Taken From: https://cdn.shopify.com/s/files/1/1975/4441/products/bed31aa0-27fa-45d8-bda8-2490fa23e524.png?v=1501766254

Our Planet's Extreme Environments by Codrington

Pages 45-46

Taken From: https://images-na.ssl-images-amazon.com/images/I/51iEP8gWFJL._SX353_BO1,204,203,200_.jpg

Glaciation and Periglaciation by Knight

Pages 42-54

Exam style Question

Examine the relative importance of glacial (ice) erosion and deposition for the development of pyramidal peaks and terminal moraines. [10 marks]