1. Color, Trace Fossils, Weathering, and Soils Causes of Color Common Trace Fossils Weathering Processes - Physical Weathering - Chemical Weathering Weathering Products - Soils - Paleosols Text: Manual p. 15, 89; Boggs Ch.1, 114-122

2. Causes of Color yellowgoethite, jarositecement brownFe-oxidescement redFe-oxidescement, coatings purplehematite (coarse)cement pinkK-feldspar, hematitecement, framework whitekaolinite, gypsum, no organics cement, bleaching greenglauconite, chlorite, illitecement, framework blackorganics, oil, heavy minerals, pyrite, Mn-oxide cement, framework colormineraloccurrence

3. Color, Trace Fossils, Weathering, and Soils Causes of Color Common Trace Fossils Weathering Processes - Physical Weathering - Chemical Weathering Weathering Products - Soils - Paleosols Text: Manual p. 15, 89; Boggs Ch.1, 114-122

4. Trace Fossils Ichnofacies (Boggs, p. 118) Environment

5. Color, Trace Fossils, Weathering, and Soils Causes of Color Common Trace Fossils Weathering Processes - Physical Weathering - Chemical Weathering Weathering Products - Soils - Paleosols Text: Manual p. 15, 89; Boggs Ch.1, 114-122

6. Physical Weathering no change in mineral / chemical composition Physical Weathering: Break-down rock into smaller pieces

7. Physical Weathering 1. Granite 2. Partially-Weathered Granite 3. Granite Grus

8. roots / lichens freeze-thaw wet-dry hot-cold Physical Weathering

10. Exfoliation Enchanted Rock batholith http://www.governor.state.tx.us/

11. Physical Weathering Spheroidal Weathering Costa Rica

12. Physical Weathering Painted Desert, Utah Gullying

13. Bryce Canyon Physical Weathering

14. Chemical Weathering alter chemical and mineral composition disrupt fabrics Chemical Weathering: Dissolution and/or crystallization of new minerals

15. Chemical Weathering Feldspar + H + + H 2 O  kaolinite + silicic acid + K + or Na 2+ Hydrolysis: H + breaks down silicates

16. Chemical Weathering pyrite Oxidation / Reduction: O alters Fe silicates and S minerals http://web.wt.net/~daba/Mineral/index.htm pyrite pyrite  hematite silicate mineral  Fe-oxide

17. Chemical Weathering Fe-oxide Stains (E. McBride) Bastrop, TX

18. Chemical Weathering Solution: dissolve in water pyrite http://www2.nature.nps.gov/ (E McBride) Limestone Karen Rills calcite / dolomite gypsum halite

19. Physical/Chemical Weathering bench slope cliff Differential Weathering Grand Canyon

20. Physical/Chemical Weathering Differential Weathering “Toadstools” Utah

21. Physical/Chemical Weathering Differential Weathering burrows

22. Color, Trace Fossils, Weathering, and Soils Causes of Color Common Trace Fossils Weathering Processes - Physical Weathering - Chemical Weathering Weathering Products - Soils - Paleosols Text: Manual p. 15, 89; Boggs Ch.1, 114-122

23. clastic sediments residues (source rock) secondary minerals ions in solution Weathering Products Soils and Sed. Rocks

24. Weathering Products Terrigenous Clastic Sediments

25. Weathering Products Evaporites Death Valley, CA www.geol.binghamton.edu/faculty/lowenstein/dv/deathvalley.html Chemical Sediments courtesy Matt Campbell Cements (M. Campbell)

26. Soils mineral residues rock fragments organics Horizons Soil Profile http://www.cjnetworks.com/

27. Soils Horizons Soil Profile http://www.cjnetworks.com/ O - organic matter A - topmost mineral horizon E - (eluvial) leaching B - (illuvial) accumulation C - weathered bedrock R - bedrock

28. Soils bedrock time climate topography

29. Pedocal Soils Pedalfer Soils 30 inches of rain per year http://www.mhhe.com/earthsci/geology/mcconnell/wss/soil.htm Soils

30. color texture structure consistency contacts

31. Soils Texture

32. FIGURE 3-26FIGURE 3-26 FIGURE 3-28FIGURE 3-28 FIGURE 3-30FIGURE 3-30 FIGURE 3-29FIGURE 3-29 columnar crumb platy blocky Soils Structure

33. ClassesDescription Non-plastic A roll 4 cm long and 6 mm thick that supports its own weight held on end cannot be formed. Slightly plastic A roll 4 cm long and 6 mm thick can be formed and, if held on end, will support its own weight. A roll 4 mm thick will not support its own weight. Moderately plastic A roll 4 cm long and 4 mm thick can be formed and will support its own weight, but a roll 2 mm thick will not support its own weight. Very plastic A roll 4 cm long and 2 mm thick can be formed and will support its own weight. Consistency: Plasticity Soils

34. Standard USDA Soil Description Form Soils

35. Color, Trace Fossils, Weathering, and Soils Causes of Color Common Trace Fossils Weathering Processes - Physical Weathering - Chemical Weathering Weathering Products - Soils - Paleosols Text: Manual p. 15, 89; Boggs Ch.1, 114-122

36. Paleosols

37. colors (red, green, purple) root casts caliche vertical streaks mottled bedding

38. Paleosols Paleosols Painted Desert, AZ

39. Root Casts Paleosol, near Hunt, TX Paleosols

40. vertical streaks (bleaching) (E. McBride) Paleosol Bastrop, TX

41. Paleosols (E. McBride) “terra rossa” fill

42. Reference Soil Survey Manual, 1993, Soil Conservation Service, USDA Handbook 18.