1. Section 15.2 Glacial Movements and Erosion

2. How do glaciers move? What are some reasons why glaciers move?
Heavy snow fall
Steep slopes
Temperature increase/summer
What slows glaciers down?
Friction

3. Slip and slide on a layer of water (friction)

4. 2 main types of glacial movement
1. Basal slip
2. Plastic flow

5. 1. Basal slip
Basal slip = immense weight of the glacier puts pressure on the bottom causing grains of ice to partially melt
creates a slushy layer
glacier “slips and slides” on the slush

6. 2. Plastic Flow Due to pressure (weight) of snow above
Grains of ice actually deform and flatten
Ice in the interior of the glacier moves forward like a plastic putty

8. As a glacier moves… Crevasses form
cracks in the glacier due to increased speed often associated with a steep incline

9. What happens at the end of a glacier?
If the glacier is below the snowline…
ice front -the ice starts to melt, signifying the end of the glacier

10. What happens at the end of a glacier?
If the snowline is at sea level…
calving -large pieces of glacier break off of the front (icebergs!)

11. How do glaciers cause erosion?
Till -breaking down boulders, rocks, pebbles, and small grains into smaller pieces
Moraine -the accumulation of till

12. The Ransom Moraine is a large moraine that cuts diagonally across Kendall County

13. Aftermath of glaciers
Striations -occur when the glacial load scratches parallel groves in the underlying bedrock
Roches mountonnees
a distinct pattern of rocks that are often exposed that bare a resemblance to a flock of sheep. “sheep rocks”