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Environmental Geology and Earth
ResourcesChapter 11
ECONOMIC GEOLOGY AND
MINERALOGY• 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)
Strategic Metals and Minerals
• Durable, highly valuable, and easily portable, gemstones and precious
metals have been a way to store and transport wealth.
– These valuable materials have bankrolled despots, criminal gangs, and
terrorism in many countries.
– Much of the illegal trade ends up in the $100 billion per year global
jewelry trade, two-thirds of which sells in the U.S.
ENVIRONMENTAL EFFECTS
OF RESOURCE EXTRACTION• Mining
– Placer Mining - Hydraulically washing out metals deposited in streambed gravel.• Destroys streambeds and fills water with suspended solids.
– Strip-Mining or Open-Pit Mining• Large scars on land surface.
• Tailings– Toxic runoff
– Underground Mining• Very Dangerous
– Gas
– Inhaling Particulate Matter
– Tunnel Collapse
• Environmental Dangers…
http://geology.cr.usgs.gov/pub/open-file-reports/ofr-95-0023/summit.htm
Polluted waters over 70 km
downstream
After making $98 Million in gold,
declared bankruptcy in 1992
EPA Superfund site- over $120
million to clean it up
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Restoration
• Surface Mining Control and Reclamation
Act (1977) requires better restoration of
strip-mined lands, especially if land classed
as prime farmland.
– Difficult and expensive.
• Often more than $10,000.00 per hectare.
– 50% of U.S. coal is strip-mined.
CONSERVING GEOLOGIC
RESOURCES• Recycling
– Aluminum must be extracted from bauxite by electrolysis.
• Recycling waste aluminum consumes 1/20 the energy of extraction from raw ore.
– Nearly two-thirds of all aluminum beverage cans in U.S. are recycled.
– Other metals commonly recycled:
• Platinum, gold, copper, lead, iron, steel.
• 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.
Tectonic Processes
Tectonic Processes GEOLOGIC HAZARDS
• Earthquakes
– Tsunami - Seismic sea swells.
• Volcanoes
– “Ring of fire”
• Floods
– 70% of population lives along coast, ~20% in flood-
prone areas.
• Landslides
Review all in the text.
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Recent earthquakes
http://earthquake.usgs.gov/
‘Tidal’ Waves…Tsunami
“harbor wave”
Tidal wave Dec 26th, 2004- Indonesia
Deaths: 321,000; Injured: 125,000
Missing: 45,752; Displaced: 1.69 million
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“Ring of Fire” Volcanoes
• 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
Floods
• Excess water that overflows stream/lake banks and
covers adjacent land.
– Biggest economic loss is usually contamination, not
direct property losses.
• Carpet, furniture, drywall, etc.
– Many human activities increase both severity and
frequency of floods.
• Soil compaction, habitat loss
• Floodplains often help mitigate flooding.
– Usually flat, fertile, and easily farmed.
New Orleans, Sept 2005
80% of was flooded
Erosion• Landslides
– A general term for rapid down-slope movement of soil or rock.
• Many human activities such as forest clearing and building homes on steep,
unstable slopes increase both frequency and damage done by landslides.
http://landslides.usgs.gov/recent/images/laconchita/LaConchita0105_sm.mov
http://landslides.usgs.gov
Nara Prefecture (Japan), August 2004.
