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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 Erosion.

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Glaciers

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  1. Glaciers

  2. 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.

  3. Factors Affecting Glacier Erosion • The rock fragments or abrasives that their base that are used to scrape the underlying bedrock. Larger rocks are better abrasives.

  4. Factors Affecting Glacier Erosion • 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.

  5. Factors Affecting Glacier Erosion • The downward force of the abrasives on the bedrock.

  6. 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.

  7. 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.

  8. Types of Glaciers • Continental Glaciers • Huge glaciers that cover a large area (polar regions). • Thickest at the centre. • Movement is in all directions away from the centre.

  9. Types of Glaciers • Valley Glaciers • Glaciers that form in mountainous regions. • Snow accumulates at the highest point and then flows down the mountain due to gravity.

  10. Geological Feature Created by Glaciers • Kettle Lake A 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

  11. Kettle Lakes in Ontario – Puslinch Lake

  12. Geological Feature Created by Glaciers • 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.

  13. Results of Glacial Erosion • 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.

  14. Results of Glacial Erosion 4. 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.

  15. Results of Glacial Erosion • 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.

  16. Mountain Features created by Glacial Erosion • Cirques • Deep depressions in the mountains that have been hollowed out by glaciers.

  17. Mountain Features created by Glacial Erosion 7. Aretes • A sharp-edged ridge of rock formed between adjacent cirques.

  18. Mountain Features created by Glacial Erosion 8. Horn • A high mountain peak that forms when the walls of three or more glacial cirques meet. • The Matter Horn

  19. Mountain Features created by Glacial Erosion 9. Tarn • A small lake that fills the central depression of a cirque. • Lake Louise in Banff

  20. Alpine Glacier Erosion 10. Glacial Valley • Glacial valleys have a u-shape cross section. They are step sided valleys cut by fast moving, warm ice.

  21. Ireland Country Side

  22. Homework • p. 203 #1-5 • P. 206 – the four questions.

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