Environmental Geology,

1
Chapter 12

• Environmental Geology,
• Processes, Minerals Soils

2
Geology

• Geology is the study of the Earths dynamic
  process with respect to its interior and surface
  structure and features. Rocks, minerals,
  chemicals, earthquakes, and volcanoes are studied
  to reveal information about our planet.
• Review the handout from Chapter 6 on the
  geosphere.

3
Geosphere

• Core central, innermost part of the Earth with
  a solid part surrounded by hot, liquid molten
  material
• Mantle thick solid region that surrounds the
  core and has zones of molten rock that flows
  (asthenosphere)
• Crust thin, outermost region of the geosphere
• Note that the lithosphere is composed of the
  upper mantle and the crust!

4
Plate Tectonics

• Tectonic plates constant movement of the rigid
  plates due to heat (energy) flow of materials
• Plate tectonics is the theory that explains the
  movement of the plates and the processes that
  occur at their boundaries
• Plate motion has produced mountains, ocean
  ridges, trenches and other features
• Plate movement provides many minerals we use as
  resources
• Continental drift helps to explain migration and
  evolutionary patterns

5
Global Geological Information

• Internal process that occur under the Earths
  surface
• See figure 12-3 (a) for a map of earthquakes and
  volcanoes along bands on the earth
• See figure 12-3 (b) for a map of plate boundaries

6
Plate Boundaries

• Divergent plate boundaries plates move in
  opposite directions
• Convergent plate boundaries plates move toward
  each other
• Transform faults plates that slide past each
  other

7
Erosion Weathering

• External process that happen on the Earths
  surface
• Erosion is the process where matter is dissolved,
  loosened or worn away from one place to another
  (ex. streams)
• Weathering is the mechanical or chemical process
  that provides change to the surface matter
• Mechanical physical changes (ex. frost wedging)
• Chemical decompose by reaction (ex. acid rain)

8
Rocks

• Minerals elements inorganic compounds that
  occur naturally (ex. gold)
• Rocks large continuous part of the earths crust
  many consist of 2 or more minerals
• Rock types 3 broad classifications are
• Igneous formed from molten rock (ex. lava)
• Sedimentary impaction of sediment (ex. shale)
• Metamorphic rock that has been subjected to
  high temperature, high pressure, chemical
  activity or a combination of these (ex. marble)

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Rock Cycle

• The rock cycle is the interaction of processes
  that continuously change rocks over time
• Recycles materials over millions of years
• Slowest of all Earths cycling processes
• Concentrates the Earths non-renewable resources

10
Mineral Resources

• Non-renewable resources mineral resources that
  take millions to billions of years to occur
• Ore is mineral resources mined for profit
• Metallic mineral ex. iron copper
• Nonmetallic mineral ex. salt clay
• Energy resources ex. coal oil

11
USGS Mineral Catagories

• The USGS has 4 classifications for non-renewable
  mineral resources
• Identified resources known location, quantity
  and quality
• Undiscovered resources assumed to exist with
  unknown data
• Reserves identified resource that can be
  extracted and sold for a price
• Other reserves undiscovered and identified
  resources that are not classified as reserves

12
Detection Methods

• Several methods are used to detect minerals
• Aerial photos satellite images - outcrops
• Radiation-measuring equipment detect deposits
• Magnetometer record changes in the Earths
  magnetic field
• Gravimeter measures differences in gravity due
  to density differences in various ore deposits
• Underground methods deep well drilling core
  samples
• Seismic surveys analyzing shock waves by
  detonation
• Chemical analysis leaching into water plants

13
Mining

• Surface mining equipment strips away the
  surrounding and unwanted material called the
  overburden (as waste it is called spoil)
• open-pit mining equipment digs a hole
  extracts ore
• Dredging draglines scrape up underwater
  minerals
• Area strip mining terrain flattened prior to
  digging
• Contour mining cuts terraces into the terrain
• Mountain-top removal explosives powerful
  shovels expose ore
• Sub-surface mining deep vertical shafts,
  explosives, heavy equipment used for extraction

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Environmental Impacts of Mining

• Scarring disruption of terrain
• Collapse of land above mines
• Toxin laced mining waste air pollution
• Acid mine drainage
• Overall effects on the health of humans and
  wildlife can be devastating

15
Mineral Supply

• Economic depletion cost is more to find and
  process than its worth on the open market
• Recycle or reuse
• Waste less
• Use less
• Find a substitute
• Do without
• Depletion time depletion /time
• Should we continue to mine?

16
General Mining Law of 1872

• 500 payment 100/20acres
• Management of timber minerals
• Opens land for mineral development
• Sell off mineral rich public land
• Turn management over to state local governments

17
Mining Lower Grade Materials

• Achieved with current technologies
• Can be limited by
• Increase cost of mining large quantities of ore
• Availability of fresh water
• Environmental impact of increased waste
  pollution
• Environmental impact of disrupting the ecosystem
  surrounding the mine

18
Microbes in Mining

• Bio-mining or in-situ mining is done by
  inoculating an ore vein with microbes that act on
  a specific ore
• Microbe loosens the ore and provides a means to
  extract it by flooding the mine
• Flood water is filtered for the desired ore and
  recycled back to the mine
• Ex. Copper ore is digested by thiobaccillus
  ferroxidans
• Bio-mining is a slow process

19
Natural Hazards

• An ecosystem can be disrupted by natural hazards
• Volcanic eruption
• Hurricanes
• Tornadoes
• Earthquakes
• Floods
• Do the Natural Hazards Lab
• Prepare a poster or Power Point presentation
  that compares contrasts 2 natural hazards

20
Soil Resources

• Complex mixture of
• Eroded rock
• Mineral nutrients
• Decayed organic matter
• Water
• Air
• Organisms (decomposers)
• Renewable resource

21
Mature Soil Soil Zones

• Soil Profile cross section view of the
  horizontal zones in the soil O Surface covered
  with leaves
• A Top soil is composed of a porous mixture of
  decomposed matter and minerals
• B Sub-soil composed of rocks and other
  inorganic matter
• C Parent mineral which lies above the bedrock

22
Soil Types

• Infiltration water percolates (seeps) into the
  zones of soil
• Leaching water picks up minerals as it
  infiltrates and carries them to lower zones
• Soil types in different locations
• Desert
• Grassland
• Tropical rainforest
• Deciduous forest
• Coniferous forest

23
Soil Permeability Porosity

• Soil permeability the rate at which water
  infiltrates the soil
• Soil porosity - of pores/volume of soil
• Loams is best for growing crops contain equal
  parts of
• Clay holds water
• Sand drains easily
• Salt - minerals
• Humus organic matter

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Soil pH and Nutrient Concentration

• Acidity (acidic) pH is between 1-6.5
• If too acidic, neutralize with lime fertilize
• Neutral pH is around 7
• Alkalinity (basic) pH is between 7.5 14
• If too basic, add sulfur
• Perform the soil lab

25
Soil Erosion

• Movement of soil from place to place
• Loss of fertile land
• Build up of soils on land and in water
• Erosion is occurring faster than soil can form
• Globally -15 erosion total and 40 of the
  agricultural property has eroded
• US - 1/3 of the prime soil in the US has eroded
• USDA states the soil is eroding 16x faster than
  it forms
• USDA states conservation efforts are working

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Desertification

• Desertification is the process of turning fertile
  land into desert
• Drought long periods without precipitation
• Unsustainable human activity lack of
  conservation efforts and respect for our land
• Overgrazing
• Deforestation
• Surface mining
• Erosion
• Salination
• Soil compaction

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Salination

• Salination occurs with a concentration of salts
  in the soil
• Irrigation containing salts in the water
• Evaporation and transpiration processes leave
  salts behind
• Salts build up to a critical level

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Waterlogging

• Waterlogging occurs when there is too much water
  remaining on land
• Precipitation irrigation percolates downward
• Water table (underground water levels) rise

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Little Sodus Bay (LSB)
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Drumlin on LSB Lake Ontario
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Drumlin Erosion East of LSB
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Soil Conservation

• 1985 Farm Act strategy to reduce soil erosion
  in the US
• Reduce erosion restore fertile land
• Conservation tilling disturb soil as little as
  possible
• Terracing reduce erosion on slopes
• Contour farming plant along contours of gentle
  slopes
• Strip cropping planting alternate strips of
  crops
• Alley cropping planting between shrubs and
  trees
• Wind breaks
• Gully reclamation fast growing vines and shrubs

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Restoring Soils

• Organic material
• Animal dung, adds nitrogen to the soil and
  stimulates bacterial fungial action
• Green manure green vegetation tilled into the
  soil
• Compost rich organic matter produced by
  bacteria from decomposed organic matter in the
  presence of oxygen

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Important Nutrients

• Commercial fertilizers contain
• Nitrogen (N) important for protein production
  in plants
• Potassium (K) - potash primary agricultural
  nutrient for food crops
• Phosphorous (P) phosphates - essential nutrient
  from rocks

Soil Lab