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Chp

VIEWS: 3 PAGES: 46

									        Chapter 12
Mineral and Soil Resources
     Copper Basin, Tennessee
   19th century
   Copper mining
   Open-air smelters
   Trees cut to provide
    wood for smelters
   Sulfur dioxide formed -
     acid precipitation
   Ecological ruin
    Copper Basin, Tennessee
 1970s: replanting techniques
 Plants had to be reestablished: why?

 Area improving

 Return of forest

  will take decades
              Basic Geology
   Lithosphere
     Earth’s outermost
      layer
     Seven large plates

     Floats on
      asthenosphere
   The plates move:
    plate tectonics
            Plate Tectonics
   Plate boundary
      Where two plates meet

      Intense geologic activity

      Earthquakes, volcanoes

   Formation of mountains
   Atlantic Ocean growing: separating plates
Plates & Boundaries
  Plate
Boundaries
                Volcanoes
   Movement of tectonic plates on hot
    soft rock
   Heat melts rock  magma
   Lava: magma
    at surface
   Environmental
    impacts of
    eruptions?
              Earthquakes
   Rocks in lithosphere shift or break
   Energy released as seismic waves
   Usually along fault
   Focus: where quake begins
   Epicenter: directly above focus
   More than 1 million quakes per year
   Measure using Richter scale
    Side Effects of Earthquakes
   Landslides
   Tsunamis
     Giant sea waves

     Indian Ocean 2004

     Waves over 30 m

     More than 225,000
      died
                Rock Cycle

   Aggregates of one
    or more minerals
   Based on rock
    formation
      Igneous rock

      Metamorphic
       rock
      Sedimentary rock
           Important Minerals
   Sulfides: contain sulfur
   Oxides: contain oxygen
   Metals
      Malleable, lustrous, conductors

      Iron, aluminum, copper

   Nonmetallic minerals
   Ore
      Rock with valuable mineral
Minerals & Their Uses
         Extracting Minerals

   Locate deposit
   Analyze mineral composition
   Mine for minerals: many different ways
   Process mineral
   Make product
           Surface Mining
   Near the surface
   Less expensive
   Overburden removed
   Open-pit
     Dig quarry

     Iron, copper,
      gravel
            Surface Mining
   Strip mining
      Dig trench to extract mineral

      Dig parallel trench

      Cover old trench with new overburden

      Spoil bank
          Subsurface Mining
   Minerals deep in ground
   Less land disturbance
   More expensive
   More hazardous
   Shaft mine
      Direct

       vertical shaft
      Coal
          Subsurface Mining
   Slope mine
      Slanting passage

      Ore hauled in cars
          Processing Minerals

   Smelting
      Melt ore to separate
       impurities from
       desired mineral
      Blast furnace

      Slag disposed of
     Mining & The Environment
   Disturbs land
   Land prone to erosion  further damage
   Uses a lot of water
   Contaminated streams
   Acid-mine drainage
         Impacts of Refining

   About 80% of mined ore made of
    impurities
   Tailings
      Waste left

       behind
      Left in piles

      Toxic
          Impacts of Refining
   Smelting emits pollutants
   Acid precipitation
   Hazardous solid and liquid wastes
   A lot of energy required
    Restoration of Mining Lands
   When mine no longer profitable
   Prevents further degradation
   Filling in and grading the area
   Planting vegetation
   Surface Mining Control
    & Reclamation Act of
    1977
   Lands mined for coal
            Soil: What Is It?

   More than just dirt!
   Uppermost layer of
    Earth’s crust
   Mineral and organic
    matter
   Living organisms
   We depend on it: how?
            Soil Formation
   Formed from parent
    material
   Biological, chemical
    and physical
    weathering processes
   Continuous process
   Topography plays a
    role: how?
   Takes a long time
            Soil Composition
   Four main parts
   Mineral particles
      Main component

      From parent material

      Provides anchorage and minerals

   Organic matter
      Living or formerly living matter

      Humus

   Air
   Water
                 Soil Profile
   Look at horizons: layers
   O horizon: surface layer
   A horizon: topsoil
     Deep in grassland soils

     Thinner in forest, tropical soils

   B horizon: subsoil
   C horizon: parent material
   Materials leach through the layers
Soil Profile
             Soil Organisms

   Soil is alive!
   Plant roots, insects, earthworms, moles,
    etc…
   Bacteria most numerous
   Fungi, algae, protozoa
   Provide ecosystem services: examples?
Soil Organisms
Decomposition
   Nutrient cycling
   Pathway of nutrient
    minerals or elements
   Sign of balanced
    ecosystem
              Soil Problems

   Our activities cause many problems
      Soil erosion

      Mineral depletion

      Soil pollution

   Sustainable soil use
      Wise use of soil resources

      Keep soil productive for the future
               Soil Erosion
   Movement of soil
   Natural process
   Accelerated today
   Water, wind
   Major effects
     Loss of soil

      fertility
     Soil cannot retain as much water

     Runoff into bodies of water
              Soil Erosion
   Poor soil management
   Agriculture, road
    building, logging
   Plant cover limits
    erosion
              Soil Pollution
   Physical or chemical change in soil
   Adversely affects health of organisms
   Some from fertilizers, pesticides
   Salinization
      Result of irrigation

      Can render soil

       useless
           Soil Conservation
   Only 11% world’s soil suitable for
    agriculture
   Much already degraded
         Conservation Tillage
   Residues from previous
    crops left in soil
   Reduces erosion up to
    70%
   More than 1/3 U.S.
    cropland
   Soil has more organic
    material
   Drawbacks?
              Crop Rotation

   Planting a series crops in the same field
    over a period of years
   Decreases insect damage
   Reduces erosion
   Rotated crops depend
    on where you farm
               Terracing
   Used on very
    steep slopes
   Like stairs
   Very
    expensive!
             Other Methods
   Contour plowing
      Farm with the natural contours of the
       land
   Strip cropping
      Strips of differing crops
            Soil Reclamation
   Badly eroded land
     Prevent further erosion

        Seed bare ground

        Plant shelterbelts

     Restore soil fertility

        Soil must recover
         first
        Restrict farming?
    U.S. Soil Conservation Policies

   Food Security Act of 1985
      Farm Bill

      Conservation compliance

         Highly erodible land

         Must have 5 year conservation plan

         Lose federal subsidies
    U.S. Soil Conservation Policies
   Food Security Act of 1985
      Conservation Reserve Program (CRP)

         Voluntary program

         Take land out of production for 10–15
          years
         Receive subsidy

         Reduced soil erosion

         Wildlife habitat
       Case Study: Industrial
           Ecosystems
   Industrial ecology
      Efficient use of resources

      “Wastes” are potential products

   Mimic natural ecosystems
   Kalundborg, Denmark
      Link different industries
Kalundborg, Denmark
       Case Study: Industrial
           Ecosystems
   Takes many years to develop
   Economy and environment benefit: how?

								
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