1. Chapter 8 page 180 Mass Movements, Wind and Glaciers

2. Section 8.1 Mass Movements at Earth’s surface
Mass movement: The down slope movement of loose sediments and weathered rock caused by gravity.
Erosion is transport of sediments and is the step that follows weathering.

3. Section 8.1 Mass Movements at Earth’s surface
Weathering is the break down of materials and erosion is the transport of these materials.
Climate determines how much material is available for mass movement.

4. Variables that influence mass movement:
The materials own weight
2. Viscosity: The materials resistance to sliding or flowing.

5. Variables that influence mass movement:
Trigger: Something to shake up the ground like an earthquake.

6. 4. Water: Not enough, sediments do not stick
4. Water: Not enough, sediments do not stick together --> Mass movement
Too much, saturates the soil making it very heavy --> Mass movement

7. Type of mass movements
Creep: Slow mass movement (a few cm per year)
Look for tilted signs or fence posts as a clue.

9. Flows: Mass movement where earth materials flow as if it were a liquid.
23,000 people died in this city and had no warning that it was coming. Recently 39 people in Brazil died the same way.

10. Land slides Before After

11. This is an example of slump
This is an example of slump. Notice the crescent shaped feature on the slope as a result.

12. This is an Avalanche. Some are set off on purpose with explosives
This is an Avalanche. Some are set off on purpose with explosives. Why is this?

14. This is a typical rock fall. There are rock fall signs in Elizaville
This is a typical rock fall. There are rock fall signs in Elizaville. This is caused by gravity and a trigger such as an earth quake, or in our case frost action.

15. Luckily no one was driving here at the time of the fall.

17. Some things that can be done to help prevent soil erosion and rock falls are erosion barriers.

18. Section 8.2 Wind
Wind can erode (carry and move) particles in one of three ways.
1. Rolling : Along the ground
2. Suspension: Carried in the air for long distances
3. Saltation: Bounces along the ground (the most common for sand grains)

19. Here is large scale saltation. A city is being swallowed by
advancing sand dunes.

20. Deflation: The lowering of the land surface that results from the removal of surface particles due to the wind.

21. Abrasion: When particles of sand rub against the surface of rocks or other materials.
Ventifacts: Rocks shaped by wind blown sediments, such as those shown below.

22. Dune: Book by Frank Hurbert
Dune: A pile of sand created by the wind.
The shape of the dune depends on the area of formation.

23. Barchan Dunes - are crescent-shaped dunes with the points of the crescents pointing in the
downwind direction, and a curved slip face on the downwind side of the dune. They form in areas
where there is a hard ground surface, a moderate supply of sand, and a constant wind direction.

24. Transverse Dunes - are large fields of dunes that resemble sand ripples on a large scale. They
consist of ridges of sand with a steep face in the downwind side, and form in areas where there is
abundant supply of sand and a constant wind direction. Barchan dunes merge into transverse
dunes if the supply of sand increases.

25. Parabolic (also called blowout) Dunes - are "U" shaped dunes with an open end facing upwind. They
are usually stabilized by vegetation, and occur where there is abundant vegetation, a constant wind
direction, and an abundant sand supply. They are common in coastal areas.

26. Longitudinal Dunes - are long straight dunes that form in areas with a limited sand supply and converging
wind directions.

27. Loess: Thick wind blown silt deposits.

28. Glacier: A large moving mass of ice.
Section 8.3 Glaciers
Glacier: A large moving mass of ice.
-They currently cover 10% of Earth’s surface
-They reside at high latitudes (Antarctica + Greenland)
-Last ice age ended 10,000 years ago
-The last ice age was responsible for creating most of the lakes in NY

29. There are two types of glaciers
1. Valley (alpine)
2. Continental (ice sheet)
Valley glacier: Form in high mountainous areas. When they advance, they carve u shape valleys.

30. Continental Glacier: Ice mass that covers a broad, continent sized area.

31. Products of Glacial erosion (page 201 in text)

32. Cirques: A deep depression carved out by a valley glacier.
Arete: the ridge formed when two cirques are side by side.
Horn: The steep pyramid shaped peak
Moraine: The unsorted deposit of a glacier after it begins to melt and retreat.

33. Outwash plain: The area at the leading edge of the glacier, where the melt water streams flow and deposit outwash.
Drumlins: The elongated landforms that are created when a glacier moves over older moraines.
Esker: Long winding ridges of layered (sorted) sediments that are deposited by the streams flowing under a melting glacier.

34. Drumlins: The elongated landforms that are created when a glacier moves over older moraines.

35. Esker: Long winding ridges of layered (sorted) sediments that are deposited by the streams flowing under a melting glacier.

36. There are three types of lakes formed by glaciers.
1. Kettle lakes: When the ice scrapes out a small area and deposits ice. A kettle hole is formed and when the ice melts it becomes a lake.

37. 2. Cirque lake: When a cirque fills with water and becomes a lake.

38. Moraine damned lake: When a terminal moraine blocks off a valley and the valley fills with water.