Post on 22-Aug-2020
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Chapter 15
Geology and Nonrenewable Mineral
Resources
Core Case Study: The Nanotechnology Revolution
Nanotechnology uses science and engineering to create materials out of atoms and molecules at the scale of less than 100 nanometers. Little environmental harm:
• Does not use renewable resources.
Potential biological concerns.• Can move through cell membranes:
Figure 15-1
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 earth’s 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 earth’s crust and upper mantle.
Figure 15-2
Fig. 15-2, p. 336
Volcanoes
Folded mountain belt
Abyssal floor
Oceanic ridge
Abyssal floor TrenchAbyssal hills
Craton
Abyssal plain
Oceanic crust (lithosphere)
Continental shelf
Continental slope
Continental rise
Continental crust (lithosphere)
Mantle (lithosphere)
Fig. 15-3, p. 337
Spreading center Ocean
trench
Subduction zone
Oceanic crust
Continental crust
Continental crust
Material cools as it reaches
the outer mantle
Cold dense material falls back through
mantleHot
material rising
through the
mantle
Mantle convection
cell
Two plates move towards each other. One is subducted back into the mantle on a falling convection current.
Mantle
Hot outer core Inner
core
Collision between two continents
Oceanic crust
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GEOLOGIC PROCESSES
Huge volumes of heated and molten rack moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface. Tectonic plates: huge rigid plates that are
moved with convection cells or currents by floating on magma or molten rock.
The Earth’s Major Tectonic Plates
Figure 15-4
Animation: Geological Forces
PLAYANIMATION
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The Earth’s 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
Fig. 15-4, p. 338
Fig. 15-4a, p. 338
EURASIAN PLATENORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
CARIBBEAN PLATE
PHILIPPINE PLATE
ARABIAN PLATEAFRICAN
PLATEPACIFIC PLATE SOUTH
AMERICAN PLATENAZCA
PLATEINDIA-
AUSTRALIAN PLATE
SOMALIAN SUBPLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
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Fig. 15-4b, p. 338
Trench Volcanic island arc Craton
Transform fault
Lithosphere
Lithosphere Lithosphere
Asthenosphere Asthenosphere Asthenosphere
Divergent plate boundaries Convergent plate boundaries Transform faults
Rising magma
GEOLOGIC PROCESSES
The San Andreas Fault is an example of a transform fault.
Figure 15-5
Wearing Down and Building Up the Earth’s Surface
Weathering is an external process that wears the earth’s surface down.
Figure 15-6
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Fig. 15-6, p. 340
Parent material (rock)
Biological weathering (tree roots and lichens)
Chemical weathering (water, acids, and gases)
Physical weathering (wind, rain, thermal expansion and contraction, water freezing)
Particles of parent material
MINERALS, ROCKS, AND THE ROCK CYCLE
The earth’s crust consists of solid inorganic elements and compounds called minerals that can sometimes be used as resources. Mineral resource: is a concentration of
naturally occurring material in or on the earth’s crust that can be extracted and processed into useful materials at an affordable cost.
General Classification of Nonrenewable Mineral Resources
The U.S. Geological Survey classifies mineral resources into four major categories: Identified: known location, quantity, and quality
or existence known based on direct evidence and measurements.
Undiscovered: potential supplies that are assumed to exist.
Reserves: identified resources that can be extracted profitably.
Other: undiscovered or identified resources not classified as reserves
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General Classification of Nonrenewable Mineral Resources
Examples are fossil fuels (coal, oil), metallic minerals (copper, iron), and nonmetallic minerals (sand, gravel).
Figure 15-7
Fig. 15-7, p. 341
Undiscovered Identified
Reserves
Eco
no
mic
al
Other resources
Dec
reas
ing
co
st o
f ex
trac
tio
n
No
t ec
on
om
ical
Decreasing certainty Known
Existence
GEOLOGIC PROCESSES
Deposits of nonrenewable mineral resources in the earth’s crust vary in their abundance and distribution.
A very slow chemical cycle recycles three types of rock found in the earth’s crust: Sedimentary rock (sandstone, limestone).
Metamorphic rock (slate, marble, quartzite).
Igneous rock (granite, pumice, basalt).
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Rock Cycle
Figure 15-8
Fig. 15-8, p. 343
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
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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Fig. 15-9, p. 344
Surface mining
Metal ore Separation of ore from gangue
Smelting Melting metal
Conversion to product
Discarding of product (scattered in environment)
Recycling
Fig. 15-10, p. 344
Natural Capital Degradation
Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources
Steps Environmental effects
Mining Disturbed land; mining accidents; health hazards, mine waste dumping, oil spills and blowouts; noise; ugliness; heat
Exploration, extraction
Processing
Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat
Transportation, purification, manufacturing
Use
Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat
Transportation or transmission to individual user, eventual use, and discarding
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
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
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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Fig. 15-13, p. 346
Undisturbed land
Overburden
PitBench
Spoil banks
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
Mining Impacts
Metal ores are smelted or treated with (potentially toxic) chemicals to extract the desired metal.
Figure 15-15
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SUPPLIES OF MINERAL RESOURCES
The future supply of a resource depends on its affordable supply and how rapidly that supply is used.
A rising price for a scarce mineral resource can increase supplies and encourage more efficient use.
SUPPLIES OF MINERAL RESOURCES
Depletion curves for a renewable resource using three sets of assumptions. Dashed vertical
lines represent times when 80% depletion occurs.
Figure 15-16
Fig. 15-16, p. 348
A Mine, use, throw away; no new discoveries; rising prices
Recycle; increase reserves by improved mining technology, higher prices, and new discoveriesB
Pro
du
ctio
n
Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveriesC
Present Depletion time A
Depletion time B
Depletion time C
Time
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SUPPLIES OF MINERAL RESOURCES
New technologies can increase the mining of low-grade ores at affordable prices, but harmful environmental effects can limit this approach.
Most minerals in seawater and on the deep ocean floor cost too much to extract, and there are squabbles over who owns them.
Getting More Minerals from the Ocean
Hydrothermal deposits form when mineral-rich superheated water shoots out of vents in solidified magma on the ocean floor.
Figure 15-17
Fig. 15-17, p. 350
Black smoker
White smoker
Sulfide deposits
Magma
White clamWhite crab Tube
worms
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USING MINERAL RESOURCES MORE SUSTAINABLY
Scientists and engineers are developing new types of materials as substitutes for many metals.
Recycling valuable and scarce metals saves money and has a lower environmental impact then mining and extracting them from their ores.
Fig. 15-18, p. 351
Solutions
Sustainable Use of Nonrenewable Minerals
• Do not waste mineral resources.
• Recycle and reuse 60–80% of mineral resources.
• Include the harmful environmental costs of mining and processing minerals in the prices of items (full-cost pricing).
• Reduce subsidies for mining mineral resources.
• Increase subsidies for recycling, reuse, and finding less environmentally harmful substitutes.
• Redesign manufacturing processes to use less mineral resources and to produce less pollution and waste.
• Have the mineral-based wastes of one manufacturing process become the raw materials for other processes.
• Sell services instead of things.
• Slow population growth.
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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Case Study: The Ecoindustrial Revolution
Figure 15-19
Fig. 15-19, p. 352
Sludge
Pharmaceutical plant Local farmers
SludgeGreenhouses Waste
heat
Waste heat Fish farming
Oil refinery Surplus natural gas
Electric power plant
Surplus sulfur
Waste calcium sulfate
Cement manufacturer
Sulfuric acid producer
Wallboard factory Area homes