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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.