Geology

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Chapter 14

• Geology

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

• Concept 14-1A Gigantic plates in the earths
  crust move very slowly atop the planets mantle,
  and wind and water move the matter from place to
  place across the earths surface.
• Concept 14-1B Natural geological hazards such as
  earthquakes, tsunamis, volcanoes, and landslides
  can cause considerable damage.

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GEOLOGIC PROCESSES

• The earth is made up of a core, mantle, and crust
  and is constantly changing as a result of
  processes taking place on and below its surface.
• The earths interior consists of
• Core innermost zone with solid inner core and
  molten outer core that is extremely hot.
• Mantle solid rock with a rigid outer part
  (asthenosphere) that is melted pliable rock.
• Crust Outermost zone which underlies the
  continents.

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GEOLOGIC PROCESSES

• Major features of the earths crust and upper
  mantle.

Figure 15-2
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Spreading center
Ocean trench
Collision between two continents
Oceanic tectonic plate
Oceanic tectonic plate
Plate movement
Plate movement
Tectonic plate
Oceanic crust
Oceanic crust
Subduction zone
Continental crust
Continental crust
Material cools as it reaches the outer mantle
Cold dense material falls back through mantle
Hot material rising through the mantle
Mantle convection cell
Mantle
Two plates move towards each other. One is
subducted back into the mantle on a falling
convection current.
Hot outer core
Inner core
Fig. 15-3, p. 337
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GEOLOGIC PROCESSES

• Huge volumes of heated and molten rock moving
  around the earths interior form massive solid
  plates that move extremely slowly across the
  earths surface.
• Tectonic plates huge rigid plates that are moved
  with convection cells or currents by floating on
  magma or molten rock.

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The Earths Major Tectonic Plates
Figure 15-4
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The Earths Major Tectonic Plates

• The extremely slow movements of these plates
  cause them to grind into one another at
  convergent plate boundaries, move apart at
  divergent plate boundaries and slide past at
  transform plate boundaries.

Figure 15-4
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GEOLOGIC PROCESSES

• The San Andreas Fault is an example of a
  transform fault.

Figure 15-5
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Earthquakes
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Alaska
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(No Transcript)
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Tsunami
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Eruptions
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Aa Aa

• Pahoehoe

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Tephra
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Mid Atlantic Ridge
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Shield Volcano
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Cinder Cone
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Stratovolcano or Composite Volcano
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Caldera
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Mt. St. Helens
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Hot Spots
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Pompeii
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Wearing Down and Building Up the Earths Surface

• Weathering is an external process that wears the
  earths surface down.

Figure 15-6
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Erosion
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Wind Erosion
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Chemical Weathering
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14-2 How Are the Earths Rocks Recycled?

• Concept 14-2 The three major types of rocks
  found in the earths crustsedimentary, igneous,
  and metamorphicare recycled very slowly by the
  process of erosion, melting, and metamorphism.

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Erosion
Transportation
Weathering
Deposition
Igneous rock Granite, pumice, basalt
Sedimentary rock Sandstone, limestone
Heat, pressure
Cooling
Heat, pressure, stress
Magma (molten rock)
Melting
Metamorphic rock Slate, marble, gneiss, quartzite
Fig. 15-8, p. 343
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14-3 What Are Mineral Resources, and what are
their Environmental Effects?

• Concept 14-3A Some naturally occurring materials
  in the earths crust can be extracted and made
  into useful products in processes that provide
  economic benefits and jobs.
• Concept 14-3B 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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ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

• The extraction, processing, and use of mineral
  resources has a large environmental impact.

Figure 15-9
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ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

• Minerals are removed through a variety of methods
  that vary widely in their costs, safety factors,
  and levels of environmental harm.
• A variety of methods are used based on mineral
  depth.
• Surface mining shallow deposits are removed.
• Subsurface mining deep deposits are removed.

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Open-pit Mining

• Machines dig holes and remove ores, sand, gravel,
  and stone.
• Toxic groundwater can accumulate at the bottom.

Figure 15-11
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Area Strip Mining

• Earth movers strips away overburden, and giant
  shovels removes mineral deposit.
• Often leaves highly erodible hills of rubble
  called spoil banks.

Figure 15-12
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Contour Strip Mining

• Used on hilly or mountainous terrain.
• Unless the land is restored, a wall of dirt is
  left in front of a highly erodible bank called a
  highwall.

Figure 15-13
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Mountaintop Removal

• Machinery removes the tops of mountains to expose
  coal.
• The resulting waste rock and dirt are dumped into
  the streams and valleys below.

Figure 15-14
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Case Study The Ecoindustrial Revolution

• Growing signs point to an ecoindustrial
  revolution taking place over the next 50 years.
• The goal is to redesign industrial manufacturing
  processes to mimic how nature deals with wastes.
• Industries can interact in complex resource
  exchange webs in which wastes from manufacturer
  become raw materials for another.

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14-4 How Long Will Supplies of Nonrenewable
Mineral Resources Last?

• Concept 14-4A 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.
• Concept 14-4B 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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COAL

• Coal reserves in the United States, Russia, and
  China could last hundreds to over a thousand
  years.
• The U.S. has 27 of the worlds proven coal
  reserves, followed by Russia (17), and China
  (13).
• In 2005, China and the U.S. accounted for 53 of
  the global coal consumption.

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14-5 How Can We Use Mineral Resources More
Sustainability?

• Concept 14-5 We can try to find substitutes for
  scarce resources, reduce resource waste, and
  recycle and reuse minerals.