Transcript CH 10
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 Key Concepts Internal geologic processes External geologic processes Minerals, rocks, and the rock cycle Earthquakes and volcanoes Soil structure and formation Soil conservation Geologic Processes Structure of the Earth Fig. 10-2 p. 204 Features of the Crust Fig. 10-3 p. 205 Internal Earth Processes 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 External Earth Processes Erosion Mechanical weathering Frost wedging Chemical weathering Refer to Fig. 10-7 p. 209 Minerals and Rocks Mineral (diamond, bauxite) Rock Types Igneous (granite, lava) Sedimentary (limestone, sandstone) Metamorphic (marble, slate) The Rock Cycle Deposition Transport Sedimentary Rock Shale, Sandstone, Limestone Erosion Heat, Pressure Weathering External Processes Internal Processes Igneous Rock Granite, Pumice, Basalt Heat, Metamorphic Rock Pressure Slate, Quartzite, Marble Magma (Molten Rock) Refer to Fig. 10-8 p. 210 Natural Hazards: Earthquakes Features Magnitude Aftershocks Primary effects-s Shaking, ground displacement Secondary effects- rock slides, sink holes, tsunamis Fig. 10-9 p. 210 Expected Earthquake Damage No damage expected Minimal damage Canada Moderate damage Severe damage Fig. 10-10 p. 211 United States Natural Hazards: Volcanic Eruptions extinct volcanoes central vent magma conduit Fig. 10-11 p. 211 magma reservoir Solid lithosphere Upwelling magma See Introductory Essay p. 203 Partially molten asthenosphere Soils: Formation Soil horizons Soil profile Humus Immature soil O horizon Leaf litter A horizon Topsoil Regolith Bedrock B horizon Subsoil C horizon Young soil Parent material Fig. 10-12 p. 212 Mature soil Soil Properties Fig. 10-17 p. 217 Water Water Infiltration Leaching High permeability Low permeability Porosity/permeability Fig. 10-16 p. 216 100%clay Texture Structure pH 0 80 Increasing percentage clay 60 40 20 20 Increasing percentage silt 40 60 80 0 100%sand 80 60 40 20 100%silt Increasing percentage sand Table 10-1 p. 216 Texture Nutrient Capacity Infiltration Water-Holding Aeration Capacity 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 Tilth Soils: Erosion Sheet erosion Rill erosion Gully erosion See Fig. 10-18 p. 217 Global Soil Erosion Areas of serious concern Fig. 10-19 p. 218 Areas of some concern Stable or nonvegetative areas Soils: Degradation Desertification Evaporation Evaporation Transpiration Salinization Waterlogging Waterlogging Less permeable clay layer Fig. 10-22 p. 221 Desertification Shortage of farmland China now has more than 2.62 million square kilometres of land under desertification, twice the amount of the total available farmland in China. Sattelite pictures show that desertification is on the increase in the provinces of Inner Mongolia, Shanxi, and Qinghai, and the autonomous regions of Xinjiang Uygur and Ningxia. 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 Solutions Cont.d •Cropping methods •Strip •Contour •Terrace •Windbreaks •Land Classification Soil Restoration Organic fertilizer Animal manure Green manure-plowing vegetation under to increase organic matter Compost Crop rotation Commercial inorganic fertilizer