1. What is a Glacier? REVIEW = An accumulation of compacted snow & ice
that moves slowly under the force of gravity
2 types of glaciers:
Valley glacier = wedge-shaped stream of ice in a valley
Continental glacier = sheet of ice over all/part of a continent
(Ice caps are small ice sheets)

2. Valley Glacier

3. Valley Glacier

4. Continental Glacier

5. It is snow “on the way” to becoming glacial ice.
Firn/ Neve
= snow compressed from being buried, which has taken on a rough, granular ice form. It is in a state between snow and ice.
It is snow “on the way” to becoming glacial ice.

6. Firn / Neve

7. = the lowest level that permanent snow reaches in the summer
Snow line
= the lowest level that permanent snow reaches in the summer
Lowest snow line near poles
Highest snow line near equator
Banff Snowline

8. Glacial Movement & Erosion
Movement of glaciers:
Glaciers move due to their great weight under the force of gravity
fastest movement at the surface and
in the centre
glaciers melt at lower elevations where it’s
warmer
The melting end of a glacier is called the ice front or terminus

9. crevasse = large fissure/crack in ice
Glacier movement can cause crevasses to form
crevasse = large fissure/crack in ice

10. icebergs = chunks of glacier broken off into water
Calving = when the ice front meets a sea, and chunks of glaciers break off into the water
icebergs = chunks of glacier broken off into water

11. 2) Weathering and Erosion from glaciers:
As glaciers move, they pick up and move rock
Rock of all sizes is moved, from powder to house-sized boulders
Glaciers move rock in different ways:
rock drops on top of a glacier
rock is incorporated into a glacier
rock is dragged at the bottom of a glacier
Plucking = a glacier “freezes around” a large rock, picking it out of the ground and carrying it away

12. Glaciers can leave striations ( = parallel scratches on bedrock) because the rock material being dragged at the bottom of the glacier scratches the rock beneath it
Striations show the direction a glacier moved

13. Rock flour = fine sediment formed by the crushing of rock beneath a glacier

14. 3) Landforms caused by glacial erosion:
U-shaped Valley = a valley with a U-shape
Hanging Valley = where a shallow U-shaped valley (caused by a small glacier) is intersected by a deep U-shaped valley (caused by a large glacier)
Cirque = a semicircular basin formed at the head of a glacial valley
Arete = a sharp divide between 2 cirques
Horn = a peak formed from 3 or more cirques

15. 3) Landforms caused by glacial erosion:
U-shaped Valley = a valley with a U-shape
Hanging Valley = where a shallow U-shaped valley (caused by a small glaceir) is intersected by a deep U-shaped valley (caused by a large glacier)
Cirque = a semicircular basin formed at the head of a glacial valley
Arete = a sharp divide between 2 cirques
Horn = a peak formed from 3 or more cirques

16. 3) Landforms caused by glacial erosion:
Cirque = a semicircular basin formed at the head of a glacier

17. 3) Landforms caused by glacial erosion:
Arete = a sharp divide between 2 cirques

18. 3) Landforms caused by glacial erosion:
Horn = a peak formed from 3 or more cirques

19. *Assignment 1: Draw a “before glacier erosion” and “after glacier erosion” picture of mountains, using the diagrams on p.325 to help you.
*Assignment 2: Do 1 – 5 (Pg 325)

20. 3) Deposition by glaciers:
When glacial ice melts (e.g., at the bottom or sides of a glacier), the rock it carries gets deposited
Glacial deposits are called till
Till is unsorted (rock of all sizes is jumbled together)
Moraine = a long pile of glacial till, formed at the end or sides of a glacier
End moraine (end)
Lateral moraine (sides)
Cirque = a semicircular basin formed at the head of a glacial valley
Arete = a divide between 2 cirques
Horn = a peak formed from 3 or more cirques
Task 1 : Do 1 – 5 (Pg 325)

21. 15.3 : Glacial Deposits
Glaciers carry & deposit drift ( = foreign rock material – eg: boulders, bedrock)
There are 2 types of drift:
Till = unsorted, unstratified rock deposited directly by ice
Ex: Moraines are rock deposits of till when the glacier retreats
Ex: Drumlins are canoe-shaped hills made of till found in swarms when advancing glaciers ran over a moraine
Outwash = sorted, stratified rock deposited by streams of glacial melt-water
Ex: Eskers are winding ridges formed when sand & gravel fill melt-water tunnels beneath a glacier.

22. Drift

23. Till

24. Outwash

25. Moraines = accumulations of glacial till
Rock flour = mixture of sand & silt formed by crushing rock under a glacier
Glacial milk = milky, white melt-water due to suspended rock flour.
Kames = cone-shaped hills of stratified sand/gravel
Kettles = circular hollows formed on moraines & outwash plains
There are 3 types of lake formed from glaciation:
Cirque lakes
Kettle lakes
Moraine dammed lakes
Task : Do 1 – 5 (Pg 328)

26. Moraine

27. Glacial Milk

28. Kames

29. Kettle

30. 15.4 : Ice Ages Evidence of ice ages:
It began 2 million years ago + 4 advances of ice
Interglacial periods between advances
Many ice ages in the past
Advances + retreats occurred at the same time in both hemisphere
Hypothesis of causes of ice ages:
Change in the sun energy
Volcanic dust in the atmosphere
Continents blocking ocean mixing
Changes in earth axis & orbits   
Task : Do 1 – 5 (Pg 333)

31. Ice Age

32. Ice Age