Figure 91 Page 173

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Figure 9-1Page 173
CHAPTER 9 ENVIRONMENTAL GEOLOGY PROCESSES,
MINERALS AND SOILS
COMPARE THIS TO WHAT HAPPENED IN EASTERN
WASHINGTON WITH OVERGRAZING AND GRASSES. EASTERN
WASHINGTON EVEN TODAY HAS SERIOUS PROBLEMS WITH
WATER EROSION AND WIND LOSS OF OUR MOST
PRODUCTIVE LOESS PRAIRIE SOIL UPON WHICH WE GROW
LOTS OF WHEAT
Kansas
Colorado
Dust Bowl
Oklahoma
New Mexico
Texas
MEXICO
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Figure 9-2Page 174
PROFILE OF EARTHS CRUST AND UPPER MANTLE WITH
SUBDUCTION OF OCEANIC PLATE.
Abyssal hills
Folded mountain belt
Abyssal floor
Oceanic ridge
Trench
Abyssal floor
Craton
Volcanoes
Continental rise
Oceanic crust (lithosphere)
Continental slope
Abyssal plain
Continental shelf
Abyssal plain
Continental crust (lithosphere)
Mantle (lithosphere)
Mantle (lithosphere)
Mantle (asthenosphere)
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Figure 9-3 (1)Page 176
PLATE BOUNDARIES ARE DELIMITED BY EARTHQUAKES AND
VOLCANOES
Volcanoes
Earthquakes
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Figure 9-3 (2)Page 176
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
PHILIPPINE PLATE
PACIFIC PLATE
AFRICAN PLATE
COCOS PLATE
Mid- Indian Ocean Ridge
SOUTH AMERICAN PLATE
Transform fault
Carlsberg Ridge
East Pacific Rise
SOMALIAN SUBPLATE
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
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Figure 9-5Page 178
Sedimentary Rock Shale, sandstone, limestone
Deposition
Transportation
Erosion
Heat, pressure, stress
Weathering
EXTERNAL PROCESSES
INTERNAL PROCESSES
Igneous Rock Granite, pumice, basalt
Metamorphic Rock Slate, marble, quartzite
Heat, pressure
Cooling
Melting
Magma (molten rock)
ROCK TYPES ARE FORMED AS PART OF TECTONIC PLATE
MOVEMENT
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• MINERAL natural element or inorganic compound.
  It is a solid. Can be pure element, but usually
  inorganic compounds.
• Mineral Resource is material of earths crust
  that can be extracted and processed into useful
  materials in a profitable manner. Some are
  metallic (Fe, Cu and Al), some non-metallic
  (salt, clay, sand, phosphates and soil).
• Energy Resources are also from earths crust and
  include coal, oil, natural gas and uranium.
• Igneous rock from molten magma or lava (granite)
• Sedimentary rock from smaller (weathered and
  eroded) fragments that are deposited in a body of
  surface water (sandstone, shale and limestone)
• Metamorphic high temp. and pressure partially
  melt pre-existing rock and/or subject it to
  chemically active fluids (anthracite coal, slate
  and marble)

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Figure 9-7 (1)Page 179
THE SERIES OF SLIDES THAT FOLLOW ARE WAYS OF
EXTRACTING MINERAL DEPOSITS
Open Pit Mine
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Figure 9-7 (2)Page 179
Dredging
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Figure 9-7 (3)Page 179
Area Strip Mining
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Figure 9-7 (4)Page 179
Contour Strip Mining
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Figure 9-8 (1)Page 181
Underground Coal Mine
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Figure 9-10Page 182
Subsurface Mine Opening
Surface Mine
Runoff of sediment
Acid drainage from reaction of mineral or ore
with water
Spoil banks
Percolation to groundwater
Leaching of toxic metals and other compounds from
mine spoil
Leaching may carry acids into soil
and groundwater supplies
SOME ENVIRONMENTAL IMPACTS OF MINING EXTRACTION
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Figure 9-11Page 183
STEPS IN THE PROCESSING OF A METAL RESOURCE
SMELTING CAUSES BAD AIR POLLUTION
Smelting
Separation of ore from gangue
Melting metal
Conversion to product
Metal ore
Recycling
Discarding of product
Surface mining
Scattered in environment
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NATURAL HAZARDS

• VOLCANOES
• EARTHQUAKES
• FLOODS

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Figure 9-13Page 186
Two adjoining plates move laterally along the
fault line
Liquefaction of recent sediments causes
buildings of sink
Earth movements cause flooding in low-lying areas
Landslides may occur on hilly ground
Shock waves
Epicenter
Focus
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Figure 9-14Page 187
WHERE EARTHQUAKE DAMAGE CAN BE EXPECTED
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Soil Is A Valuable Renewable Resource

• Soil - a complex, living resource
• We depend on soil for life, yet tend to take it
  for granted.
• U.S. - at least 20,000 different soil types
• Building good soil is a slow process
• About 30-50 of the worlds croplands are losing
  topsoil faster than it can be replaced.

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Soil Profile
SOILS CONSIST OF LIVING AND NON-LIVING COMPONENTS
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Figure 9-17Page 190
Rove beetle
Pseudoscorpion
Flatworm
Centipede
Ant
Ground beetle
Mite
Roundworms
Adult fly
Fly larvae
Beetle
Springtail
Mite
Protozoa
Millipede
Bacteria
Sowbug
Slug
Fungi
Actinomycetes
Snail
Mite
Earthworm
Organic debris
LIVING ORGANISMS ARE PART OF SOIL HEALTH
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Figure 9-18 (1)Page 191
CLIMATE INFLUENCES SOIL DEVELOPMENT
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)
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Figure 9-18 (2)Page 191
VEGETATION INFLUENCES SOIL TYPE
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Figure 9-19Page 192
DRAINAGE IS A FUNCTION OF PARTICLE SIZE (SAND,
SILT AND CLAY)
Water
Water
High permeability
Low permeability
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Land Resources
GENERAL ASPECTS OF LAND RESOURCES

• Cropland per person averages only 0.7 acres
  worldwide. By 2025, this could decline to 0.42
  acres.
• In developed countries, 95 of recent
  agricultural growth has come from improved crop
  varieties or increased fertilization, irrigation,
  etc.
• Land conversion - ecological trade-offs

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Worldwide Soil Degradation
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Mechanisms of Erosion

• Most soil erosion on agricultural land is rill
  erosion
• Some of the highest erosion rates in the world
  occur in the U.S. and Canada - row crops leave
  soil exposed

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Erosion The Nature of the Problem

• Erosion - natural process, but a disaster when it
  occurs in the wrong place at the wrong time
• Rill erosion
• Gully erosion

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Figure 9-22Page 195
DESERTIFICATION AND SEMIARID LANDS
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Ways We Use and Abuse Soil
Much potential cropland suffers from constraints.
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Figure 9-23Page 195
CAUSES OF DESERTIFICATION AND WHY IT IS BAD
Consequences
Causes
Worsening drought Famine Economic losses Lower
living standards Environmental refugees
Overgrazing Deforestation Surface
mining Erosion Salinization Soil compaction
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Figure 9-24Page 196
Transpiration
Evaporation
Evaporation
Evaporation
Waterlogging
Less permeable clay layer
PROBLEMS WITH IRRIGATION
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Figure 9-25Page 196
Prevention
Cleanup
Reduce irrigation Switch to salt- tolerant
crops (such as barley, cotton, sugar beet)
Flushing soil (expensive and wastes water) Not
growing crops for 2-5 years Installing under-
ground drainage systems (expensive)
WAYS TO PREVENT or LIMIT SALINIZATION
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Figure 9-26Page 197
Advantages
Disadvantages
Reduces erosion Saves fuel Cuts costs Holds
more soil water Reduces soil compaction Allows
several crops per season Does not reduce crop
yields
Can increase herbicide use for some
crops Leaves stalks that can harbor crop pests
and fungal diseases and increase pesticide
use Requires investment in expensive equipment
CONSERVATION TILLAGE CAN BE MINIMUM OR NO TILL
FARMING
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WAYS OF IMPROVING AGRICULTURAL PRACTICES INCLUDE

• TERRACING
• CONTOUR PLANTING
• STRIP CROPPING
• ALLEY CROPPING
• WINDBREAKS

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Managing Topography

• Contour Plowing
• Strip-farming
• Terracing
• Planting perennial species

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Reduced Tillage

• Minimum till
• Conserv-till
• No-till

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Figure 9-28Page 200
Inorganic Commercial Fertilizers
Advantages
Disadvantages
Easy to transport Easy to store Easy to
apply Inexpensive to produce Help feed one
of every three people in the world Without
commercial inorganic fertilizers world food
output could drop by 40
Do not add humus to soil Reduce organic matter
in soil Reduce ability of soils to hold
water Lower oxygen content of soil Supply only
2 or 3 of 20 or so nutrients needed by
plants Require large amounts of energy to
produce, transport, and apply Release the
greenhouse gas nitrous oxide (N20) Runoff can
over- fertilize nearby bodies
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THIS IS THE END OF CHAPTER 9 BUT HOPEFULLY A
BEGINNING TO YOUR UNDERSTANDING THAT MOST OF THE
WORLD'S ENVIORNMENTAL PROBLEMS, ALTHOUGH
INTIMIDIATING IN SIZE AND COMPLEXITY, ARE SOLVABLE