1. Glacial Erosion
Chapter 4.2

2. Key Questions
How do glaciers form and move? How do glaciers cause erosion and deposition?

3. Glacier
Any large mass of ice that moves slowly over land.

4. Glaciers can form only in an area where more snow falls than melts.
How do glaciers form?
Glaciers can form only in an area where more snow falls than melts.

5. What makes Glaciers look blue? Refer to page 128
Glacial ice is denser than snow and it does not absorb the shorter blue light rays.

6. A glacier that covers much of a continent or large island.
Continental glacier
A glacier that covers much of a continent or large island.
Continental glaciers can flow
in all directions as they move.

7. Continental Glaciers today
Presently Continental Glaciers cover 10% of Earth’s land.
They cover Antarctica and most of Greenland.

8. Ice Ages
Times in Earth’s history during which glaciers covered large parts of the surface. About 1 million years ago they covered about 1/3 of the earth. Most recently retreated about 10,000 years ago.

9. Valley glacier
A long, narrow glacier that forms when snow and ice build up high in a mountain valley.

10. How do glaciers move?
Continental glaciers can flow in all directions as they move.

11. How do glaciers move? Gravity constantly pulls a glacier downhill.
Once the layer of snow and ice is about 30 meters deep- glacier begins to move.(About how many feet deep?)
30 Meters is about 100 Feet Deep
Valley glaciers flow at a rate of a few centimeters to a few meters per day.

12. Glacial Erosion What did the glaciers do to the area?

13. How do glaciers cause erosion?
The two processes by which glaciers erode the land are plucking and abrasion.

14. Plucking
The process by which a glacier picks up rocks as it flows over the land. Many of the “plucked” rocks remain on the bottom and are dragged – gouging the bedrock. This is called abrasion.
Plucking 

15. How do glaciers cause deposition?
When a glacier melts, it deposits the sediment it eroded from the land, creating various landforms.

16. Till
The mixture of sediments deposited directly on the surface by a glacier. Till is made up of many different sizes from clay  silt  sand  gravel boulders.

17. A ridge formed by the till deposited at the edge of a glacier.
Moraine
A ridge formed by the till deposited at the edge of a glacier.

18. Kettle
A small depression that forms when a chunk of ice is left in glacial till.

19. Kettle Lakes

20. Glacial Landforms

21. Enhancement Glacial Overview:
8_s

22. Glacier National Park
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Glacier Bay National Park Map
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