1. WEATHERING EROSION SOIL FORMATION
EARTH SCIENCE CHAPTER 7
WEATHERING
EROSION
SOIL FORMATION

2. Appalachians Today

3. Appalachians 400 mya

5. 7.1 Weathering
What is it?
2 types

6. Cleopatra's Needle
before
after

7. Mechanical (physical)—rocks are broken down into smaller pieces
Gravity—
Temperature—
Ex: frost wedging
Pressure--
Ex: exfoliation

9. Why do bridges have expansions joints?

10. Potholes!

11. Exfoliation of
granite

12. Gravity = rockslide

13. Old Man in the
Mountain
Before…..

14. ….after

15. Review Definitions:
Weathering—rocks at Earth’s surface are broken down and changed
Erosion—
Deposition—
SO? All of these processes have been going on since Earth began!

16. Why is the Statue
Of Liberty
Green?

17. Chemical weathering— Hydrolysis— Oxidation— Carbonic acid—
EX: decomposition of silicates
Oxidation—
EX: rust
Carbonic acid—
Karst Topography

20. Acid rain—pH of rain < 5.6
acidic
neutral
basic

21. Acid rain

24. What can affect rates of weathering?
Climate—
Chemical—
Mechanical—
Type of rock—
Surface area—
Topography—erosion in areas of high relief (steep) w/ deposition in areas of low relief (flat)

25. Physical weathering in cool
Dry climate

26. Chemical weathering
In warm and wet
climate

27. How does surface area
Affect weathering?

28. 7.2 Erosion and Deposition

29. Agents of erosion Gravity— Running water— Glaciers— Wind—
Rivers, streams, water falls
Glaciers—
Wind—
Plants and animals (biological)—

30. GRAVITY EROSION

31. RUNNING WATER EROSION

32. GLACIAL EROSION
WIND EROSION
PLANT EROSION

33. Biological erosion

34. Rill
Erosion

35. Gully
erosion

36. 1930’S DUST BOWL CAUSED BY EROSION
OF TOPSOIL DUE TO EXTENSIVE
OVERFARMING AND DROUGHT

37. A word about beaches….
Ocean waves are constantly rebuilding and shaping coastlines
Sandbars can become barrier islands but they are not permanent!
Barrier islands threatened by hurricanes and beach erosion and rising sea levels

38. Barrier
islands

39. Hurricane Sandy before and after

40. Soil formation What is soil? Loose
Formed by chemical, mechanical and biological activity over very long periods of time
Humus—

41. SO? The texture of a soil affects its capacity to
Soil Texture:
Sand—
Silt—
Clay—
SO? The texture of a soil affects its capacity to

45. Soil profile A vertical sequence of soil layers Residual soil—
Transported soil—

47. VA soil profiles