1. Weathering & Erosion Chapter 14

2. Weathering Natural process by which atmospheric and environmental agents change, disintegrate, and decompose rocks Wind, rain, temperature changes

3. Mechanical Weathering Weathering by physical means Does not change rock composition, only makes it smaller Ice, plants, animals, gravity, running water, and wind Exfoliation – peeling off of layers of rock

4. Exfoliation

5. Mechanical Weathering Ice wedging –Freeze-thaw cycles break off rock pieces Abrasion –Gravity, running water, and wind Organic activity –Root growth, burrowing animals

6. Chemical Weathering Rock breaks down by means of chemical reactions Oxidation –Rocks with iron will rust (Georgia red clay) Hydrolysis –Rock reacts with water

7. Chemical Weathering Carbonation –Carbonic acid reacts with rocks to form carbonates (Acid rain) Organic Acids –Acids produced by living organisms –Lichens, mosses

8. Chemical Weathering Acid precipitation –Burning fossil fuels –NO x + H 2 O  HNO x –SO x + H 2 O  H 2 SO x

9. Surface Area

10. Rates of Weathering Differential Weathering –Softer rock weathers faster than harder rock Rock composition –In general, sedimentary weathers fastest Exposure –Surface area, fractures, joints

11. Rates of Weathering Climate –Alternating hot and cold climates --- fastest weathering –Warm, humid climates --- fairly fast –Hot, dry climates --- slowest Topography / Elevation –Elevation and slope increases weathering

12. Rates of Weathering Human Activities –Mining, construction, rec activities can increase rates

13. Rates of Weathering Plant and Animal Activity –Roots and burrowing can weaken rock –Bigger animals bring smaller animals that can burrow into rock

14. Erosion Materials loosened, dissolved, or worn away and transported from one place to another by a natural agent Natural agents are wind, water, ice, or gravity

15. Sheet Erosion Layers of topsoil being stripped away

16. Soil Conservation Methods Contour Plowing Strip Cropping Terracing Crop Rotation

17. Gravity & Erosion Mass Movement –Rockfalls –Landslides –Mudflows –Slumps –Solifluction –Creep

18. Landslides

19. Landforms Mountains Plains – flat & at sea level Plateaus – flat & at high elevation

20. Mountains Tetons – uplift & erosion Appalachians – only erosion

21. Buttes & Mesas Buttes Mesas