1. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Glaciation
Earth once covered with glaciers
Last glaciation ended around 10,000 years ago

2. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Glaciers
Rivers of ice that move slowly
Move downslope under the influence of gravity and the pressure of own weight
Form where rate of accumulation of snow and ice is greater than rate of melting
Largest reservoir of fresh water on Earth

3. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Types of glaciers
Valley glaciers: form in mountainous locations and move down valleys
Continental ice sheets/glaciers: enormous areas of glacial ice and snow

4. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Causes of an ice age
Change in the Earth’s orbit around the sun
Change in the angle of the Earth’s axis

6. 2 processes of erosion

7. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Processes of glacial erosion
Glaciers erode the landscape they travel over in two ways:
Plucking
Abrasion

8. Chapter 13: Glacial Processes, Patterns and Associated Landforms
1. Plucking
Bottom of glaciers scrape along valley floors – creates friction causing melting around the base of the glacier
Meltwater refreezes
Freezes around the rocks on the valley floor and these become part of the glacier
Glacier moves
Newly trapped rock is plucked out of the valley floor
New material is then used in process of abrasion

9. Chapter 13: Glacial Processes, Patterns and Associated Landforms
2. Abrasion
bedrock beneath the glacier is eroded by the debris/material embedded in the sides and bottom of the glacier
‘Sandpaper effect’ – scrapes the rock over which it is travelling and leaves scratches or grooves in the rock
Striations – show the direction of the ice flow

11. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Factors affecting the rate of glacial erosion
Thickness of ice
Topography
Geology
Gradient
Accumulation and ablation

12. Features of erosion

13. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial erosion (Features of erosion)
Cirque
Birthplace of a glacier
Three steep sides
Also called a corrie or coom
Arête
Narrow ridge
Formed when two cirques formed side-by-side or back-to-back

14. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial erosion (continued)
3. Pyramidal peak
Peak at top of mountain
three or more cirques are eroded back-to-back around the sides of a mountain…leaving a peak

15. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial erosion (continued)
4. U-shaped valley
Glacier moves through this valley, changing the shape from a V-shape to a U-shape
Valleys have steep sides and flat floors
Glacier cuts off interlocking spurs of the V-shaped valley leaving truncated spurs

16. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial erosion (continued)
5. Ribbon lakes
Long, narrow lakes found in glaciated U-shaped valleys
meltwater and rainwater accumulates forming a ribbon lake
6. Fjords
Drowned U-shaped valleys
Result of melting glaciers

18. Features of
erosion
Ribbon lake
Cirque/lake
U-shaped valley
Hanging valley
Pyramidal peak
Arete

19. Features of deposition

20. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Glacial deposition
Dropping or laying down of sediment that was once transported by a glacier
Occurs in lowland areas
Deposited material is called glacial drift
Material deposited directly by ice is called till or boulder clay
Material deposited by glacial meltwater is known as fluvio-glacial deposits

21. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Examples of landforms of glacial deposition
Moraines
Drumlins
Erratics

22. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Examples of landforms of fluvio-glacial deposition
Eskers
Outwash plains
Kames and kettleholes

23. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
Moraine
Deposited debris
Various sizes ranging from large boulders to fine rock flour
Material may be angular or rounded in shape

24. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Five types of moraine
Lateral moraine
Medial moraine
End/terminal moraine
Ground moraine
Englacial moraine

25. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
2. Drumlins
Oval-shaped hills consisting of boulder clay
Show direction of glacier movement
Occur in swarms or cluster
‘Basket of eggs’ topography
‘Drowned drumlins’ – as the ice melted sea levels rose and the drumlins appear as islands in the sea

26. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
3. Erratics
Material transported by the glacier and are said to be ‘out of place’ when deposited
Esker – long winding ridges of stratified sand and gravel that wind its way across lowland areas

27. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
4. Outwash plains
Glaciers melt
Release vast amounts of water
Spreads outwards beyond the end/terminal moraine
Carries large volumes of rock and gravels and sands

28. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
5. Kames
Piles of sediment consisting of gravels and sand
Deposited along the front of a retreating glacier

29. Chapter 13: Glacial Processes, Patterns and Associated Landforms
Landforms of glacial deposition
6. Kettle holes
Blocks of ice separate from the main glacier
Buried partly in meltwater sediments
Blocks of ice melt leaving depressions or holes
Fill with water – form kettle hole lakes

31. Glacial deposition