Environmental Geology
Prof. Steven Dutch
Office: LS 463
Phone: 465-2246
Email: dutchs@uwgb.edu
Home Page: www.uwgb.edu/dutchs
Minerals
• Toxins
– Hg, Cd, As, etc.
• Carcinogens
– Asbestos, Silica Sand
• Radiological hazards
– Uranium and Thorium decay series (U, Th, Ra, Rn,
Po)
• Hazards arise from:
– Bulk Chemistry
– Trace impurities
– Physical State
Igneous Rocks and Volcanoes
• Direct volcanic hazards
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Lava Flows
Ash falls
Pyroclastic flows
Mudflows
Landslides and cone collapse
Floods
Gases
• Climatic effects
– Stratospheric ash
– Sulfur aerosols
• Super-Volcanoes
– Magma chamber collapse
– Flood basalts
Surface Water
• Lack of potable water is the single greatest hazard to human health
– Women in arid developing regions spend up to 1/3 of their time
gathering water
– Diarrhea from contaminated water is the single greatest cause of infant
mortality.
– Aid workers have to fight to convince mothers that diarrhea is not a
normal childhood disease
• Problems with surface water
– Disease organisms
– Contamination by pollutants and sewage
• Overuse of Surface Water
– "Whiskey's for drinking, water's for fighting over."
– Owens Valley, California
– Aral Sea
Ground Water
• Mechanics of ground
water
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Recharge zone
Aquifers
Aquitards
Springs, wetlands and
lakes
– Artesian systems
– Wells
– Karst
• Human impacts on
ground water
– Cone of depression
– Migration of salt water
and contaminants
– Contamination of
aquifers
– Land subsidence
– Impact on surface
water
Soils
• No soil, no food. It's that
simple.
• Soils are complex
entities, resulting from the
interaction of:
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Time
Climate
Vegetation
Drainage
• Types of Soils
• Soil Erosion
– Poor plowing practices
– Overgrazing
– Deforestation
• Other Soil Degradation
– Climatically inappropriate
farming
– Urbanization
• Soil preservation
approaches
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Contour plowing
Strip cropping
No-till agriculture
Reforestation
Weathering and Erosion
• Floods
– River floods
– Coastal floods
– Dam Failure (Natural or Artificial)
• Mass Wasting
– Soil Creep
– Mudflows
– Avalanches
– Slumps
Deserts and Wind Erosion
• Desertification
– Expansion of deserts at the margins due to overgrazing and
deforestation
– "The Bedouin is not the son of the desert, but its father."
– North Africa was forested in pre-Roman times
– Sub-Saharan Africa
• Wind Erosion
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Loess soils feed the world
Present-day wind erosion strips topsoil
Burial of vegetation or exposure of roots
Respiratory hazards
Cost of clearing wind-blown sediment from roads
Coastal Processes
• Storm Surges
– Galveston, 1900
– Bangladesh, 1971
– New Orleans, 2005
• Subsidence
– Louisiana
• Erosion
– Effects on property values
– Attempts to control
Earthquakes
• Causes
– Plate boundaries
– Intraplate
• Hazards
– “Earthquakes don’t kill
people, Buildings kill
people”
– Tsunami
– Landslide
– Fire
• Hazard Mitigation
– Construction
– Zoning
• Prediction?
– Short Term
(Precursors)
– Long Term (Seismic
Gaps,
Paleoseismology)
Resources
• Mineral Resources
– Metallic versus non-metallic
– Extraction methods
– Environmental Impacts
• Non-Petroleum energy
resources
– Coal
– Uranium
– Geothermal
• Petroleum and Natural Gas
– Geopolitical and Geological
realities
– Petroleum production
• Non-conventional energy
sources
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Methane hydrates
Tar sands
Oil shales
Oil mining
Hot dry rock geothermal
Deep Earth gas hypothesis
Extraterrestrial Hazards
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Can we predict impacts?
The Torino Scale of Impact
Hazard
– Named for the city in Italy, not a
person
– Assesses both probability of event
and potential effects of impact
– Therefore not completely
consistent.
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Likely impact scenarios
– Atmospheric impact and air burst
(Tunguska, 1908)
– Surface impact causing local
damage
– Surface impact with 100 km
damage radius
– Surface impact with 1000 km
damage radius
– Surface impact with global effects
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What happens during impact
Environmental Effects
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Radiant heat and flash burns
Blast wave
Seismic waves
Tsunami
Ejecta
Stratospheric dust
Liberated volatiles (carbon
dioxide, sulfur, methane)
– Impact volcanism - a myth
Military Impacts on the
Environment
• Clausewitz: "War is policy carried on by other
means."
– All war is inherently political
– The last general who was utterly unconstrained was
Napoleon
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Incidental (collateral) damage
Modifications to facilitate own operations
Modifications to impede enemy
Strategic Modifications
Environmental Terrorism
Exponential Growth
• Invest one cent at 1% interest per year,
compounded annually, in the year 1 AD
• By now it would be worth $.01 x (1.01)2011 =
$4,900,000.00
• At 2%: $1,895,592,883,959,335.15 or 30 times
the total GDP of the earth
• At $1000 per ounce = 58,952,939 tons of gold.
• Total amount of gold ever mined is around
150,000 tons. You could not be paid in gold.
Exponential Growth
• Doubling time = 72 years / % annual growth rate
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4% = 18 years
3% = 24 years
2% = 36 years
1% = 72 years
• Implications for Earth
– All exponential growth, no matter how low the rate,
eventually becomes huge.
– You can't get an infinite amount of anything (like
people) into a finite space
– You can't get an infinite amount of anything (like
resources) out of a finite space
– Nothing can grow forever
Exponential Growth
• At 2% per year, global population will be:
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12 billion in 2041
24 billion in 2077
48 billion in 2113
One person per square meter (land and sea) in 2594
Equal to the mass of the earth in 3596
• What will limit growth?
– Natural methods (famine, disease and war)
– Imposed by society (China's one-child policy)
– Personal preference (Demographic Transition)
• No amount of environmental awareness will
matter unless population growth stops
Exponential Growth
• Impacts on Earth
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Diversion of primary capacity to feed humans (now at least 25%)
Destruction and fragmentation of habitat
Direct consumption of animals and plants for food and fuel
Increased degradation of land by erosion
Increased hazard to humans as populations in dangerous terrain
increase
• Prognosis
– Humans will probably always operate in crisis management
mode (not dealing with a problem always offers immediate
returns)
– Sooner or later we will miscalculate our ability to avert disaster
One Last Demographic Effect of
Population Growth
Population
Equals
Regulation