Geology: Processes, Hazards, and Soils

1. Geology: Processes, Hazards, and Soils G. Tyler Miller’s Living in the Environment 13th Edition Chapter 10 Dr. Richard Clements Chattanooga State Technical Community College

2. Key Concepts • Internal geologic processes • External geologic processes • Minerals, rocks, and the rock cycle • Earthquakes and volcanoes • Soil structure and formation • Soil conservation

3. Geologic Processes • Structure ofthe Earth Fig. 10-2 p. 204

4. Features of the Crust Fig. 10-3 p. 205

5. Internal EarthProcesses • Plate tectonics • Divergent boundary • Convergent boundary • Subduction zone • Transform fault • Ring of Fire Refer to Fig. 10-5 p. 207 Fig. 10-6 p. 208

6. External Earth Processes • Erosion • Mechanical weathering • Frost wedging • Chemical weathering Refer to Fig. 10-7 p. 209

7. Minerals and Rocks • Mineral (diamond, bauxite) Rock Types • Igneous (granite, lava) • Sedimentary (limestone, sandstone) • Metamorphic (marble, slate)

8. The Rock Cycle Deposition Transport Erosion Sedimentary Rock Shale, Sandstone, Limestone Weathering Metamorphic Rock Slate, Quartzite, Marble Heat, Pressure External Processes Internal Processes Heat, Pressure Igneous Rock Granite, Pumice, Basalt Magma (Molten Rock) Refer to Fig. 10-8 p. 210

9. Natural Hazards: Earthquakes • Features • Magnitude • Aftershocks • Primary effects-s • Shaking, ground displacement • Secondary effects- rock slides, sink holes, tsunamis Fig. 10-9 p. 210

10. Expected Earthquake Damage No damage expected Minimal damage Canada Moderate damage Severe damage United States Fig. 10-10 p. 211

11. Natural Hazards: Volcanic Eruptions extinct volcanoes central vent magma conduit magma reservoir Solid lithosphere Partially molten asthenosphere Upwelling magma Fig. 10-11 p. 211 See Introductory Essay p. 203

12. Soils: Formation Immature soil O horizon Leaf litter A horizon Topsoil Regolith B horizon Subsoil Bedrock C horizon Parent material Young soil Mature soil • Soil profile • Humus • Soil horizons Fig. 10-12 p. 212

13. Soil Properties Fig. 10-17 p. 217 Water Water Fig. 10-16 p. 216 100%clay High permeability Low permeability 0 80 20 Increasing percentage clay Increasing percentage silt 60 40 40 60 20 80 0 80 60 40 20 100%sand 100%silt Increasing percentage sand • Infiltration • Leaching • Porosity/permeability • Texture • Structure • pH

14. Table 10-1 p. 216 Texture Nutrient Infiltration Water-Holding Aeration Tilth CapacityCapacity Clay Good Poor Good Poor Poor Silt Medium Medium Medium Medium Medium Sand Poor Good Poor Good Good Loam Medium Medium Medium Medium Medium Refer to Fig. 10-15 p. 215

15. Soils: Erosion • Sheet erosion • Rill erosion • Gully erosion See Fig. 10-18 p. 217

16. Global Soil Erosion Areas of serious concern Areas of some concern Stable or nonvegetative areas Fig. 10-19 p. 218

17. Soils: Degradation Evaporation Evaporation Transpiration Waterlogging Less permeable clay layer • Desertification • Salinization • Waterlogging Fig. 10-22 p. 221

19. Desertification

20. Solutions: Soil Conservation • Conventional-tillage • All topsoil is turned under and exposed • to erosion and the elements. • Conservation tillage • Minimum or no-till –either loosely break • the surface or use special planting equipment • to put seeds into earth without exposing • topsoil. Refer to Fig. 10-26 p. 224

21. Solutions Cont.d • Cropping methods • Strip • Contour • Terrace

22. Windbreaks • Land Classification

23. Soil Restoration • Organic fertilizer • Animal manure • Green manure-plowing vegetation under to increase organic matter • Compost • Crop rotation • Commercial inorganic fertilizer