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