1. WEATHERING

2. I. Introduction

3. II. Types of Weathering A. Mechanical/Physical B. Chemical

4. Mechanical/Physical 1. Thermal Expansion and Contraction

5. 2. Ice Wedging/Frost Action
Water expands 9% when it freezes
30,000 psi

6. 3. Exfoliation

8. 6/19/2018

9. 4. Action of Organisms

10. Biological “Critters”
Burrowing animals
Humans

11. II B. Chemical Weathering
1. Factors:
A. Type of Rock or Mineral

13. B. Amount of Surface Area

14. C. Presence of Moisture

15. D. Effects of Organisms

16. E. Air and Water Pollution
Sulfur = acid rain

17. II B. Chemical Weathering
2. Mechanisms of Chemical Weathering

18. A. Solution“the dissolving of a rock”
CO H2O = H2CO3
Carbon Carbonic Acid
Dioxide

19. A. Solution“the dissolving of a rock”
 CO H2O = H2CO3
Carbon Carbonic Acid
Dioxide
H2CO CaCO3 = Ca+ + 2HCO3-
Carbonic Limestone Bicarbonate
Acid

20. A. Solution“the dissolving of a rock”
More recently…..
2SO H2O + O2 = H2SO4

21. A. Solution“the dissolving of a rock”
More recently…..
2SO H2O + O2 = H2SO4
Sulfur Sulfuric
Dioxide Acid

22. B. Hydration “chemically adding water to a rock”
CaSO H2O = CaSO4 * 2 H20
Anhydrite Gypsum

23. C. Hydrolysis “converting a silicate mineral into a clay via water”
2KAlSi3O H2CO H20 =
Orthoclase Carbonic Acid Water
Al2Si2O5(OH)4 + 2K+ + 2HCO SiO2
Kaolinite Bicarbonate Quartz

24. D. Oxidation: “process of rusting; the taking away of electrons”
Fe2+ >>>> Fe3+
Ferrous Ferric
(dark) (red)

25. D. Oxidation: “process of rusting; the taking away of electrons”
Fe2+ >>>> Fe3+
Ferrous Ferric
(dark) (red)
4Fe O2 = 2Fe2O3
iron hematite
ore

26. III. Rates of Weathering
A. Climate

27. III. Rates of Weathering
A. Climate
B. Rock Structure, Size, Composition