1. Weathering and Erosion

2. Weathering Breakdown of rock at or near the earth’s surface 2 types of weathering – –Mechanical – –Chemical

3. Mechanical Weathering: no change in chemical composition--just disintegration into smaller pieces

4. Mechanical Weathering Types of Mechanical weatheringTypes of Mechanical weathering –Frost heaving and Frost wedging –Plant roots

5. Frost Wedging: water freezes in a crack and breaks it apart (MOST COMMON TYPES OF MECHANICAL)

8. Frost Heaving

10. Plant Roots

12. Chemical Weathering: changes or alters as a result of chemical reactions CaCO 3 +CO 2 +H 2 O ---> Ca 2+ + 2HCO 3-

13. Chemical Weathering The agents of chemical weatheringThe agents of chemical weathering –Water –Acid Rain

14. Water

15. Acid Rain Compounds from burning coal, oil and gas react with water forming acids.Compounds from burning coal, oil and gas react with water forming acids.

16. 1908 1969 Acid rain has eaten away this limestone statue.

17. Erosion The movement of weathered materials by water, wind, or glaciers

18. Water Erosion forms the largest canyons and the deepest valleys

21. Wind Erosion Picks up small particles. Usually in areas of little water or little vegetation

22. Wind Erosion

26. Erosion by Glaciers that were formed over many years as ice and snow are compressed

27. Glaciers can create lakes as they melt