Transcript Geology and Earth Resources

Geology and Earth Resources
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Outline
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Tectonic Processes
Rocks and Minerals
 Rock Cycle
Economic Geology and Mineralogy
Environmental Effects of Resource Extraction
 Mining
- Reclamation
Conserving Geologic Resources
Geologic Hazards
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Review Questions
1. Describe the layered structure of the earth.
(draw a diagram)
2. What are tectonic plates and why are they
important to us?
3. Why are there so many volcanoes,
earthquakes, and tsunamis along the “ring
of fire” that rims the Pacific Ocean?
4. Define mineral and rock.
5. Describe the rock cycle and name the three
main rock types that it produces.
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Review Questions continued
6. Figure 14.11 maps sources of some of the
most important metals. What are they, and
where do they come from?
7. Give some examples of nonmetal mineral
resources and describe how they are used.
8. Describe some ways metals and other
mineral resources can be recycled.
9. What are some environmental hazards
associated with mineral extraction?
10. Describe some of the leading geologic
hazards and their effects.
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A DYNAMIC PLANET
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Tectonic Plates
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Tectonic Plate Movement
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Pangea
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Continental Shift
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ROCKS AND MINERALS
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Rock Types
Rock Cycle
 Igneous
 Sedimentary
 Metamorphic
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Rock Cycle
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Igneous Rocks
Basalt
Granite
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Weathering and Sedimentation
Types of Weathering
 Mechanical
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Chemical
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Sedimentary Rock
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Shale
Sandstone
Tuff
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Metamorphic Rock
Marble (from limestone)
Quartzite (from sandstone)
Slate (from mudstone & shale)
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ECONOMIC GEOLOGY AND MINERALOGY
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Metals
 Metals consumed in greatest quantity by
world industry (metric tons annually):
- Iron
(740 million)
- Aluminum
(40 million)
- Manganese
(22.4 million)
- Copper and Chromium (8 million ea)
- Nickel
(0.7 million)
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Non-Metal Mineral Resources
Gemstones and Precious Metals
Sand and Gravel
Limestone
Evaporites
Sulfur
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Environmental Effects of Resource Extraction
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Placer Mining
Mining
Underground Mining:
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Strip-Mining or Open Pit Mining
- Large scars on land surface.
- Mountain top removal
- Tailings
- Toxic runoff
"Overburden Mountain", the
newest of the High Peaks.
This is a huge tailings pile in
the middle of the mine site.
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Restoration
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Surface Mining Control and Reclamation Act
(1977) requires better restoration of stripmined lands, especially if land classed as
prime farmland.
 Difficult and expensive.
- Complete reclamation often costs more
than $10,000 / hectare.
 50% of U.S. coal is strip mined.
- Mine executives are beginning to
recognize that keeping mines cleaner
from the start will make good economic
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sense.
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Processing
Metals are extracted from ores by heating or
treatment with chemical solvents.
 Smelting - Roasting ore to release metals.
- Major source of air pollution.- Ducktown,
TN release clouds of sulfur dioxide
resulting in a barren moonscape.
 Heap-Leach Extraction - Crushed ore piled
in large heaps and sprayed with a dilute
alkaline cyanide solution which percolates
through the pile to dissolve the gold.
- Effluent left behind in ponds. Summitville
Mine in Colorado.
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CONSERVING GEOLOGIC RESOURCES
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Recycling
 Aluminum must be extracted from bauxite by
electrolysis. (expensive & energy-intensive)
- Recycling waste aluminum consumes onetwentieth the energy of extraction from raw
ore.
 Nearly two-thirds of all aluminum beverage
cans in U.S. are recycled. 15% 20 yrs ago.
 Other metals commonly recycled:
- Platinum, gold, copper, lead, iron, steel.
 Look at Table 14.3
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Substituting New Materials For Old
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Reduce metal consumption by using new
materials or new technologies.
 Plastic pipes in place of metal pipes.
 Fiber-optics in place of metal wires.
 Metal alloys in place of traditional steel for
cars.
 Ceramic engine parts provide heat
insulation around pistons, bearings, &
cylinders, keeping the engine cool.
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GEOLOGIC HAZARDS
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Diseases kill more people than any other
cause.
Drought-caused famines are the second
biggest killers, including El Nino, bad
weather, and bad governance.
Floods are the natural disasters that take the
largest number of lives.
Wind storms cause the greatest property
damage.
Look at Table 14.4
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Earthquakes
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Sudden movements of the earth’s crust that
occur along faults where one rock mass
slides past another.
 Gradual movement - creep.
- When friction prevents creep, stress
builds up until eventually released with a
sudden jerk.
 Frequently occur along subduction
zones.
 Tsunami - Seismic sea swells.
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New Madrid Fault
Information will be provided on Tuesday
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Volcanoes and undersea magma
vents are the sources of most of
the earth’s crust.
• Many of world’s fertile soils are
weathered volcanic material.
 Human / Environmental
Dangers
- Volcanic Ash
- Mudslides
- Sulfur Emissions
Volcanoes
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Mass Wasting
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Materials are
moved
downslope from
one place to
another.
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Summary
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Tectonic Processes
Rocks and Minerals
Economic Geology and Mineralogy
 Strategic Resources
Environmental Effects of Resource Extraction
 Mining
- Reclamation
Conserving Geologic Resources
Geologic Hazards
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