1. Mass Movements, Wind and Glaciers
Chapter 8 Notes

2. Mass Movement….
What factors determine how fast you go down a waterslide?

3. Mass Movement: Changing the Landscape
Definition: Movement of soil and rock downslope due to gravity
All mass movements occur on slopes (i.e. almost everywhere)
Can be subtle (creep) or catastrophic (landslide) and everything in between
Range in size from small sediment to large boulders

4. Factors that influence mass movement
Climate
Composition of the earth material
Weight of the material
Friction
Triggers (an earthquake, for example)
Water/rainfall: increases weight and decreases friction

5. Types of Mass Movements
Creep
Solifluction (permafrost)
Flows
Slides
Slumps
Falls

6. Examples of Mass Movement
Creep
Slump
Note the curved crescent shape at the top of the slump.

7. Examples of Mass Movement
Flows
Slides
lahar

8. Examples of Mass Movement
Avalanche
Falls

9. Wind Erosion Moving air can transport sediment
Suspension
Saltation (bouncing motion of sand particles)
Precipitation limits wind erosion:
Precipitation promotes plant growth that anchors sediment
Moist soil is not carried as easily by wind

10. Dust Bowl: Great Plains 1930s

11. Wind Erosion and Transport
Abrasion
Deflation
Desert pavement

12. Wind Deposition When wind velocity decreases, particles are deposited.
Dunes: piles of windblown sand
Windward side is not as steep as the leeward side
Wind causes dunes to move (“migrate”)
Loess: Thick windblown silt deposits.
Loess soils are very fertile due to abundant nutrients and minerals.

13. Wind Deposition
Loess
Dunes

14. Glaciers Large moving masses of ice
Currently, 10% of Earth’s surface is covered by glaciers
Can be
Valley glaciers (alpine glaciers)
Continental glaciers

15. Valley Glaciers
Turns V-shaped river valleys into U-shaped glacial valleys

16. Glacial Erosion
U-shaped valley with hanging stream
Horn

17. Glacial Erosion
Cirque
Arête

18. Formation of a Cirque

19. Glacial Deposition

20. Glacial Deposition
Drumlin

21. Glaciers in Indiana