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GLACIERS
GLACIERS
Glacier Erosion A glacier is a large, moving mass of ice
that are found in either high elevations or near the poles.
A very large portion of Canada’s landforms and sediments are primarily glacial in origin.
Factors Affecting Glacier Erosion1. The rock fragments or abrasives that their
base that are used to scrape the underlying bedrock. Larger rocks are better abrasives.
Factors Affecting Glacier Erosion1. The amount of water under the ice sheet.
Water acts as a lubricant that increases the speed of the ice sheet. The faster it moves, the more erosion occurs.
Factors Affecting Glacier Erosion1. The downward force of the abrasives on
the bedrock.
Warm Ice versus Cold Ice Warm Ice – Ice that is around the
freezing point. Mountain glaciers contain this type of ice. It contains liquid water, moves quickly and is very erosive.
Warm Ice versus Cold Ice Cold Ice – Ice that is well below the
freezing point. It does not contain liquid water and accumulates snow very slowly. This ice is found near the poles.
Types of Glaciers1. Continental Glaciers
Huge glaciers that cover a large area (polar regions).
Thickest at the centre. Movement is in all directions away from the
centre.
Types of Glaciers2. Valley Glaciers
Glaciers that form in mountainous regions. Snow accumulates at the highest point and
then flows down the mountain due to gravity.
Geological Feature Created by Glaciers1. Kettle LakeA shaped depression
formed when a large block of glacial ice breaks away from the main glacier and is buried beneath glacial till, then melts. If the depression fills with water, it is known as a kettle lake
Geological Feature Created by Glaciers2. Erratics
These are rock fragments carried by ice from their place of origin and left in an area where there is a different type of bedrock.
These are important for scientists because they help chart the movement of ancient ice sheets.
Results of Glacial Erosion3. Moraines These are ridges or
mounds of glacial material deposited at, or close to, the ice margins.
Horseshoe Valley is a moraine.
They tell scientist how far an ice sheet reached.
Results of Glacial Erosion4. Drumlins A oval shaped hills
that are formed from glacial till. They are 15 to 40 m in height and have a length to width ratio of 1:2.
Results of Glacial Erosion5. Fjords or Sounds A glacial valley that
has been invaded by water from a large body of water like a lake or ocean.
Sounds (Like Owen Sound) are bigger than Fjords.
Mountain Features created by Glacial Erosion6. Cirques Deep depressions
in the mountains that have been hollowed out by glaciers.
Mountain Features created by Glacial Erosion7. Aretes A sharp-edged
ridge of rock formed between adjacent cirques.
Mountain Features created by Glacial Erosion8. Horn A high
mountain peak that forms when the walls of three or more glacial cirques meet.
The Matter Horn
Mountain Features created by Glacial Erosion9. Tarn A small lake that
fills the central depression of a cirque.
Lake Louise in Banff
Alpine Glacier Erosion10. Glacial Valley Glacial valleys
have a u-shape cross section. They are step sided valleys cut by fast moving, warm ice.
Ireland Country Side
Homework p. 203 #1-5 P. 206 – the four
questions.
