Geology and Nonrenewable Minerals

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Geology and Nonrenewable Minerals

• AP Environmental Science

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14-1. What Are The Earths Major Geological
Processes and Hazards?

• Gigantic plates in the Earths crust move very
  slowly atop the planets mantle, and wind and
  water move matter from place to place across the
  Earths surface.
• Natural geological hazards such as earthquakes,
  tsunamis, volcanoes, and landslides can cause
  considerable damage.

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Earth The Dynamic Planet

• Earth is divided into three main zones
• Crust Hard, cracked outer shell(Crust Solid
  Mantle Lithosphere)
• Mantle Softer rock, liquid to hard(Softer
  layer of mantle Asthenosphere)
• Core
• Inner Hottest under greatest pressure - solid
• Outer Extremely hot, but liquid

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Natural Processes Shape Earth

• Internal Processes
• Usually build up the Earths surface
• External Processes
• Usually wear down the Earths surface
• Physical weathering Wind, rain, freezing, etc.
• Chemical weathering Water, acids, gases, etc.
• Biological weathering Living things break up
  parent material

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How We Go Places Plate Tectonics

• The crust is cracked into large slabs called
  tectonic plates and float on magma
• Convection currents move plates around
• Collisions between plates cause EQ!

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Earths Major Plates
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Types of Plate Boundaries

• Where plates meet plate boundaries
• Convergent
• Plates come together, usually one dives under
  another (subduction)
• Divergent
• Plates move apart, magma bubbles up (ridges)
• Transform
• Plates move side to side

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Plate Boundaries
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Effects of Plate Tectonics

• Volcanoes
• Large hill/mountain formed due to magma reaching
  the surface
• Earthquakes
• Sudden release of stored up energy from plates
  rubbing together

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Earthquake Terms

• Focus The true location of an EQ
• Epicenter Location of EQ on surface
• Richter Scale Used to quantify EQs energy
• Amplitude Size of EQ wave on seismograph
• Aftershocks Smaller shakings after EQ
• P-Wave Primary wave
• S-Wave Secondary wave

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Tsunami!

• Series of waves generated by EQ
• No Day After Tomorrow surfer waves
• Can cause widespreaddevastation

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Tsunami Before After
Banda Aceh Shore, IndonesiaTsunami of December
28, 2004
Before
After
168,000 people died
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14.2 How Are The Earths Rocks Recycled?

• The three major types of rocks found in the
  Earths crust sedimentary, igneous, and
  metamorphic are recycled very slowly by the
  processes of erosion, melting, and metamorphism.

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The Three Types of Rocks

• Sedimentary
• Small particles pressed together
• Igneous
• Rock that forms below surface, wells up and cools
  off
• Metamorphic
• Igneous or sedimentary rock is exposed to heat,
  pressure, and chemical changes

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How Sedimentary Rock is Formed

• Parent is weathered into small pieces (sediment)
• Sediments are deposited (usually layer after
  layer)
• Pressure compacts and cements sediment into rock
• Erosion can turn rock back into sediment

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How Igneous Rock is Formed

• Igneous rock starts as magma
• As it surfaces, it cools and solidifies
  depending on how it happens, different results
• Extrusive cooling above ground, quick, only
  small crystals form
• Intrusive cooling below ground, slow, larger
  crystals form

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Examples of Igneous Rock
Diorite intrusive (notice the large
crystals/grains)
Obsidian extrusive (notice lack of
crystals/grains)
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How Metamorphic Rock is Formed

• Hardest to identify
• Igneous and sedimentary rock can be turned into
  metamorphic rock through the use of heat and
  pressure
• Heat and pressure causes a literal
  metamorphosis to occur as rocks are rearranged

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Examples of Metamorphic Rock
Gneiss(nice)
Marble
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The Rock Cycle(You need to KNOW this!)
A SLOW series of chemical orphysical processes
that canchange one type of rock intoanother
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14.3 What Are Mineral Resources and What Are The
Environmental Effects of Using Them?

• Some naturally occurring materials in the Earths
  crust can be extracted and made into useful
  products in processes that provide economic
  benefits and jobs.
• Extracting and using mineral resources can
  disturb the land, erode soils, produce large
  amounts of solid waste, and pollute the air,
  water, and soil.

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Minerals

• Mineral Resource Naturally occurring,
  inorganic, material from crust
• Ore Rock that contains a large concentration of
  a mineral
• High Grade Ore Large amount of mineral
• Low Grade Ore Smaller amount of mineral

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Ore Examples

• If you cant grow it, you have to MINE it!

Element Ore
Silicon Quartz
Aluminum Bauxite
Iron Magnetite or Hematite
Calcium Gypsum or Calcite
Sodium Halite
Magnesium Magnesite or Dolomite
Potassium Sylvite
Copper Chalcopyrite
Tin Cassiterite
Lead Galena
Zinc Sphalerite
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Estimating Mineral Resources

• Key terms used by USGS
• Identified location, quantity, and quality known
  based on direct measurements.
• Undiscovered potential supplies assumed to
  exist.
• Reserves identified resources that can be
  extracted profitably.

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Effects of Mineral Use

• No matter the mineral, all steps use large
  amounts of energy and creates pollution.
• High grade less energy needed
• Low grade more energy needed

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Harmful Effects
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Extracting Minerals from Deposits

• Surface Mining
• Remove overburden (discarded as spoils) to get to
  mineral deposits
• Types
• Open-Pit
• Strip
• Contour Strip
• Mountain-Top Removal

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Open Pit Mining

• Machines dig large holes in ground, remove ores
• Toxic water can collect at bottom of pit

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Strip Mining

• Similar to open-pit, but only useful when
  deposits are horizontal and near surface

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Contour Strip Mining

• Used in hilly or mountain areas
• Cut terraces
• Remove overburden and use to make new terrace

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Mountain-Top Removal

• Literally remove the top of mountains (!!!)

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Mountain-Top Removal Example
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Removing Metals from Ores

• Negative consequences
• Scarring/disruption of land surface
• Large amount of spoils
• Large amounts of solid waste
• Toxic or acidification of water (H2SO4, etc.)
• Gangue (gang)
• Air pollution

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14.4 How Long Will Supplies of Nonrenewable
Mineral Resources Last?

• All nonrenewable mineral resources exist in
  finite amounts, and as we get closer to depleting
  any mineral resource, the environmental impacts
  of extracting it generally become more harmful.
• An increase in the price of a scarce mineral
  resource can lead to increased supplies and more
  efficient use of the mineral, but there are
  limits to this effect.

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Depletion of Resources

• Future supply depends on two factors
• Actual supply
• Rate of use
• Depletion time
• Use up 80 of resource
• After depletion
• Recycle, waste less, use less, find a substitute,
  do without

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Economic Depletion

• As known resources are depleted, it becomes more
  expensive and difficult to get to new supplies
• We might still have resources left, but it will
  be TOO COSTLY to utilize them on a wide-scale

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U.S. General Mining Law of 1872

• To encourage mining of hard rock minerals
• How it works
• File claim that you believe land contains
  valuable minerals
• Promise to spend 500 to improve it
• Purchase public land for 2.50 to 5.00 an acre
  (!!!)
• Pay 120 a year for each 20-acre parcel of land
• Law frozen in 1995 by that time, estimated 285
  billion of public land given away at 1872
  prices
• Since clean up requirements only came in 1992,
  there are an estimated 500,000 sites that will
  cost taxpayers 32-72 billion to clean up!

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Example of 1872 Law Give Away

• In 2004, a mining company purchased 155 acres of
  public land near Crested Butte for 875
• Land could be worth 155 million
• Each year, companies remove 4 billion worth of
  minerals each year and only pay 2.3 of the value
  in tax (compared to 13.2 for oil or 14 for
  grazing rights)

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14.5 How Can We Use Mineral Resources More
Sustainably?

• We can try to find substitutes for scarce
  resources, reduce resource waste, and recycle and
  reuse minerals.

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Reclamation

• The good news Mining now requires reclamation
• Reclamation Returning the land as close as
  possible to original state.

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Industrial Ecosystems

• Design industrial process to mimic nature