1. Weathering

2. Weathering is the breaking down of rocks.

3. Mechanical weathering is the break down of rocks by physical means.

4. Examples of mechanical weathering
Ice wedging
Abrasion – grinding & wearing away of rock by mechanical means
water
2) wind
3) gravity
Repeated freezing & thawing of water that cracks rocks
Plants & animals
Pg 280

6. Chemical weathering is the break down of rocks by chemical reactions.

7. Examples of chemical weathering (p. 281)
water
Acid precipitation
Air (oxidation)

9. What about climate? How does it affect weathering?
Turn to page 286.
The more humid the climate, the faster weathering will take place.

10. Erosion

11. Erosion is the movement of sediments from one place to another.

12. Let’s take a look at an erosion video!

13. There are 4 agents of erosion

14. WATER
Moving water (waves, river, and streams) can carry sediments from one place to another.
Faster moving water carries larger sediments while slow moving water carries small ones.

16. WIND Wind carries sediment from one place to another.
Like water, faster moving wind can carry large sediments.
Wind can carry sediments far distances.

18. GLACIERS
Glaciers can carry lots of sediments because they are so large.
They move very slow and travel over land.

20. Gravity pulls sediments and materials down slope.
This is called mass movement. The steeper the slope, the faster it will move.

21. The following pictures are of fast mass movements

22. rockfall

23. rockfall

24. When a piece of land becomes detached and slides downhill.
slump
When a piece of land becomes detached and slides downhill.

25. mudflow& Lahar

26. The following picture is of slow mass movement

27. Slow downhill movement of weathered rock
creep
Slow downhill movement of weathered rock

28. Deposition

29. Deposition is the dropping of sediments.

30. All agents of erosion (water, wind, glaciers, gravity) can also be agents of deposition.

31. When water loses energy, it drops its load. This can form deltas.

32. WIND When wind loses energy, it drops its load.
These sediments begin to pile up.
They can form loess deposits or dunes.

33. When glaciers begin to melt, they drop their load.

34. GRAVITY
Gravity pulls sediments to the bottom of slopes and they begin to pile up.