Geology: Processes, Hazards, and Soils

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Geology Processes, Hazards, and Soils
Brian Kaestner Saint Marys Hall
Thanks to Miller and Clements
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Geologic Processes

• Structure ofthe Earth

Fig. 10.2, p. 212
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Composition of Earths Crust
Fig. 10.4, p. 213
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Features of the Crust
Fig. 10.3, p. 213
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Reykjanes Ridge
EURASIAN PLATE
EURASIAN PLATE
Mid- Atlantic Ocean Ridge
ANATOLIAN PLATE
JUAN DE FUCA PLATE
NORTH AMERICAN PLATE
CARIBBEAN PLATE
CHINA SUBPLATE
Transform fault
ARABIAN PLATE
PHILIPINE PLATE
PACIFIC PLATE
AFRICAN PLATE
COCOS PLATE
Mid- Indian Ocean Ridge
SOUTH AMERICAN PLATE
Transform fault
Carlsberg Ridge
East Pacific Rise
AFRICAN PLATE
INDIAN-AUSTRLIAN PLATE
Southeast Indian Ocean Ridge
Transform fault
Southwest Indian Ocean Ridge
ANTARCTIC PLATE
Plate motion at convergent plate boundaries
Plate motion at divergent plate boundaries
Convergent plate boundaries
Fig. 10.5b, p. 214
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Internal EarthProcesses

• Plate tectonics

• Divergent boundary

• Convergent boundary

• Subduction zone

• Transform fault

• Ring of Fire

• Fig. 10.6, p. 215
• Refer to Fig. 10-5 p. 214

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Lithosphere
Asthenosphere
Oceanic ridge at a divergent plate boundary
Fig. 10.6a, p. 215
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Trench
Volcanic island arc
Lithosphere
Rising magma
Asthenosphere
Subduction zone
Trench and volcanic island arc at a
convergent plate boundary
Fig. 10.6b, p. 215
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Fracture zone
Transform fault
Lithosphere
Asthenosphere
Transform fault connecting two divergent plate
boundaries
Fig. 10.6c, p. 215
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Lake
Tidal flat
Glacier
Spits
Shallow marine environment
Stream
Barrier islands
Lagoon
Dunes
Delta
Dunes
Beach
Shallow marine environment
Volcanic island
Coral reef
Continental shelf
Continental slope
Abyssal plain
Deep-sea fan
Continental rise
Fig. 10.7, p. 216
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External Earth Processes

• Erosion

• Mechanical weathering

• Frost wedging

• Chemical weathering

Refer to Fig. 10-7 p. 216
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Minerals and Rocks

• Mineral (diamond, bauxite)

Rock Types

• Igneous (granite, lava)

• Sedimentary (limestone, sandstone)

• Metamorphic (marble, slate)

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The Rock Cycle
Sedimentary Rock Shale, Sandstone, Limestone
Heat, Pressure
External Processes Internal Processes
Metamorphic Rock Slate, Quartzite, Marble
Heat, Pressure
Igneous Rock Granite, Pumice, Basalt
Magma (Molten Rock)
Fig. 10.8, p. 217
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Natural Hazards Earthquakes

• Features

• Magnitude

• Aftershocks

• Primary effects

• Secondary effects

Fig. 10.9, p. 217
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Expected Earthquake Damage
Fig. 10.10, p. 218
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Natural Hazards Volcanic Eruptions
Fig. 10.11, p. 218 See Spotlight p. 219
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Volcanoes
Earthquakes
Fig. 10.5a, p. 214
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Soils Formation

• Soil horizons

• Soil profile

• Humus

Fig. 10.12, p. 220
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Rove beetle
Pseudoscorpion
Flatworm
Centipede
Ant
Ground beetle
Mite
Roundworms
Adult fly
Fly larvae
Beetle
Springtail
Mites
Protozoa
Millipede
Bacteria
Sowbug
Slug
Fungi
Actinomycetes
Snail
Mite
Earthworms
Organic debris
Fig. 10.13, p. 221
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Soil Properties

• Infiltration

• Leaching

• Porosity/permeability

• Texture

• Structure

• pH

Fig. 10.16, p. 224
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Water
Water
High permeability
Low permeability
Fig. 10.17, p. 224
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Fig. 10.16, p. 224
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Table 10-1 p. 225
Texture Nutrient Infiltration Water-Holding Aerati
on Tilth Capacity 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
Fig. 10.15b, p. 223
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Mosaic of closely packed pebbles, boulders
Alkaline, dark, and rich in humus
Weak humus- mineral mixture
Dry, brown to reddish-brown with
variable accumulations of clay,
calcium carbonate, and soluble salts
Clay, calcium compounds
Desert Soil (hot, dry climate)
Grassland Soil (semiarid climate)
Fig. 10.15a, p. 223
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Forest litter leaf mold
Acid litter and humus
Acidic light- colored humus
Humus-mineral mixture
Light-colored and acidic
Light, grayish- brown, silt loam
Iron and aluminum compounds mixed with clay
Dark brown Firm clay
Humus and iron and aluminum compounds
Tropical Rain Forest Soil (humid, tropical
climate)
Deciduous Forest Soil (humid, mild climate)
Coniferous Forest Soil (humid, cold climate)
Fig. 10.15b, p. 223
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Global Soil Erosion
Fig. 10.19, p. 226
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Kansas
Colorado
Dust Bowl
Oklahoma
New Mexico
Texas
MEXICO
Fig. 10.20, p. 227
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Soils Degradation

• Desertification

• Salinization

• Waterlogging

Fig. 10.22, p. 229
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desertification
Fig. 10.21, p. 228
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Fig. 10.23, p. 229
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Solutions Soil Conservation

• Conventional-tillage

• Conservation tillage

• Cropping methods

• Windbreaks

Refer to Fig. 10-24 p. 230

• Land Classification

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Windbreaks
Fig. 10.24d, p. 230
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Alley cropping
Fig. 10.24c, p. 230
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Control planting and strip cropping
Fig. 10.24b, p. 230
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Soil Restoration

• Organic fertilizer

• Animal manure

• Green manure

• Compost

• Crop rotation

• Commercial inorganic fertilizer