Geology: Processes, Hazards, and Soils G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 10 G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 10 Dr. Richard Clements Chattanooga State Technical Community College 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 p. 204

Features of the Crust Fig p. 205

Internal Earth Processes  Plate tectonics  Divergent boundary  Convergent boundary  Subduction zone  Transform fault  Ring of Fire Refer to Fig p. 207 Fig p. 208

External Earth Processes  Erosion  Mechanical weathering  Frost wedging  Chemical weathering Refer to Fig p. 209

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

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

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

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

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

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

Soil Properties  Infiltration  Leaching  Porosity/permeability  Texture  Structure  pH 100%clay Increasing percentage silt Increasing percentage clay %sand %silt Increasing percentage sand Fig p. 216 Fig p. 216 Water High permeabilityLow permeability Fig p. 217

Table 10-1 p. 216 TextureNutrientInfiltrationWater-HoldingAerationTilthCapacity ClayGoodPoorGoodPoorPoor SiltMediumMediumMediumMediumMedium SandPoorGoodPoorGoodGood Loam MediumMediumMediumMediumMedium Refer to Fig p. 215

Soils: Erosion  Sheet erosion  Rill erosion  Gully erosion See Fig p. 217

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

Soils: Degradation  Desertification  Salinization  Waterlogging Evaporation Transpiration Evaporation Waterlogging Less permeable clay layer Fig p. 221

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. Desertification

Solutions: Soil Conservation  Conventional-tillage  All topsoil is turned under and exposed to erosion and the elements.  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.  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 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