Term
Flooding
Reaccurance Interval
Flood Erosion |
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Definition
-Natural process on all rivers
Recurrence interval: average time between floods of a given size.
Flood erosion: high velocity and large volume transport on floodplains. |
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Term
| What are some ways that humans increase flooding? |
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Definition
• Paved areas and storm
sewers: increase runoff by
inhibiting infiltration
• Bridges, docks, builidngs on
floodplains: restrict water
flow, increase velocity and
erosion
• Increases peak discharge
and hastens occurrence of
flood |
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Term
| What methods of flood control are commonly used? |
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Definition
1. Upstream dams:
release flood water
gradually
But…Erosion and
ecosystem destruction
below dam.
2. Artificial levees
• Restrain water within channel
3. Bypasses
• Reduce main
channel
discharge |
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Term
| •What is the history of flooding and flood control of the Hocking River in Athens and Ohio University? |
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Definition
East Green -Flood of 1964
Flood of 1968
$8.9 million in damage to Athens County and $750,000 to Ohio University.
1969-1971: $11 million Hocking River relocation project
U.S. Army Corps of Engineers estimates >$48 million in flood
damage has been averted since completion. |
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Term
|
Definition
Water filling pores in sediments and
sedimentary rocks and fractures in other
rock types
• Resupplied by slow
infiltration
of precipitation
• ~15% of rainfall
ends up as GW |
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Term
| •What is the relationship between groundwater and bedrock? |
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Definition
Different rocks hold different amounts of
water |
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Term
| Porosity and Permeability |
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Definition
Porosity: percentage of rock of sediment that
consists of voids
• Permeability: interconnectiveness of pores or
fractures, capacity for a rock to transmit fluids |
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Term
|
Definition
– Sandstone: High porosity and permeability
– Shale: Very poor porosity and permeability |
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Term
|
Definition
Aquifer - Saturated rock
or sediment through which water moves easily.
Aquitard – Precludes movement of GW due to low porosity and/or permeability. |
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Term
| •Which rocks make good aquifers? |
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Definition
– Sandstone
– Fractured rocks
– Sand and gravel |
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Term
|
Definition
– Shale, clay, unfractured
crystalline rocks |
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Term
| •What is are the vadose zone and saturated zone? |
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Definition
• Vadose zone: both air and water in pore spaces
• Saturated Zone: all pores filled with water |
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Term
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Definition
Water Table: upper
surface of zone of saturation |
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Term
| What is a perched water table; what do these produce? |
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Definition
Perched water table: top of
water table separated from main
water table by vadose region
– Produce springs |
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Term
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Definition
Deep hole used to obtain water from an
aquifer.
Recharge- Rate that water is replace to aquifer. |
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Term
|
Definition
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Term
| • What happens when more water is withdrawn from a well than is replenished via recharge? |
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Definition
If Rate of pumping > recharge, water table
will drop and cone of depression forms
– Ex. Lowered 30 m in W. TX |
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Term
|
Definition
Dropping water table can lead to ground subsidence
– Cracks foundations, roads and pipelines
– Central Valley, CA: 7
meters
• From agricultural pumping |
|
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Term
| • What are some ways groundwater can be contaminated? |
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Definition
• Pesticides, herbicides, fertilizers
• Rain leached pollutants from
landfills
• Septic tanks, sewers, etc.
• Acid mine drainage
• Industrial waste
• Radioactive waste |
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Term
| How does contaminated groundwater move away from the source (does it stay confines or does it fan out). |
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Definition
– Form plume, size increases with distance from
source
– Some rock types act as natural purifiers.
• Behavior of contaminants:
– Pumping increases flow of
contaminants
• Contaminated ground water
can be extremely difficult and
expensive to clean up!!! |
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Term
| Cool things groundwater does |
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Definition
• Caves and karst
• Petrified wood, geodes
• Hot springs, geysers |
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Term
|
Definition
• Caves - naturallyformed
underground
chambers
– Acidic ground water
dissolves limestone
along joints and
bedding planes
– Mammoth Cave, KY |
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Term
|
Definition
Speleothems – formations
when calcite ppts out of groundwater |
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Term
Sinkholes
Karst Topography |
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Definition
• Sinkholes: form from
cave collapse
• Karst topography:
rolling hills, disappearing streams, and
sinkholes |
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Term
|
Definition
• Wells tap steam that turns a turbine to
create energy
• Clean energy source: No CO2 or acid rain
are produced
– Some toxic gases given off (e.g., sulfur
compounds), lead
and mercury at
surface
– Non-renewable |
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Term
|
Definition
| A region with < 25 cm annual rainfall |
|
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Term
| • Why do deserts form (1) 10 to 15º wide belt centered on 30º N and 30º S. |
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Definition
1) 10 to 15º wide belt centered
on 30º N and 30º S
– due to Hadley cell circulation
– Ex. Sahara, W. Australia |
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Term
| (2) landward of mountain belts |
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Definition
2) Rain shadow
– Air cools and drops ppt
over mtn ranges, dry
air flows over mtns
– Ex. SW USA |
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Term
| (3) very far from the ocean |
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Definition
3) Very far from ocean
– Most rainfall is evaporated from seawater
– Ex. Northern China |
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Term
| (4) next to cold ocean currents? |
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Definition
4) Cold ocean currents
– Cool air warms over continents and causes
drying
– Ex. W coast S. Am. |
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Term
| • What are the characteristics of desert? |
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Definition
• Lack of through-flowing
streams
• Internal drainage
• Flash floods
• Angular topography |
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Term
| • On the Colorado Plateau, explain the difference in a mesa and butte? |
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Definition
Colorado Plateau: flat-lying
sedimentary and
extrusive rocks
• Plateau: broad, elevated, flat topped areas
– Mesa: isolated plateau, wider than tall
– Butte: taller than wide |
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Term
| What are basic features of the Basin and Range desert? |
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Definition
Features of the desert Southwest
Basin and Range: fault
block mtns, many
parallel mtn range
=> lots of rain
shadow |
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Term
| • What is the role of wind in the desert? |
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Definition
• Key agent of erosion, transportation, and
deposition
– Requires loose, dry particles
– Moves clay, silt, & fine sand only
– Higher velocity can move more sediment |
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Term
|
Definition
• Loess: Wind deposited layers of silt and clay-sized sediment
– 1930’s Dust Bowl: from
eroding loess during extended drought |
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Term
| • What are glaciers? What are the two types? |
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Definition
• Large, long-lasting mass of ice
formed on land that moves
downhill under its own weight
–Form where snow accumulates faster
than it melts
• Two types of glaciated terrain
–Alpine glaciation
–Continental glaciation |
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Term
| • How much of the Earth is presently covered with glaciers—how are these distributed (percentage) between Antarctica, Greenland, mountain glaciers? |
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Definition
• 10% of Earth’s surface is covered by
glaciers
• 10% in Greenland
• 85% in Antarctica
• Last 5% occur at high elevation
– Even present close to equator at high
elevations in South America and Africa.
• 75% of world’s supply of freshwater
is in glaciers |
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Term
| If these all melted, how high would sea level rise? |
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Definition
• Enough water to raise sea level by
70 m (230 ft) |
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Term
| • How does snow turn into glaciers? |
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Definition
• Snow falls as
powder
• Compaction
destroys points
• As buried, air
expelled, crystals
interlock. |
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Term
| • What are the primary characteristics of valley glaciers and continental ice sheets? |
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Definition
1. Valley Glacier: confined to a
valley
– Characterizes alpine glaciation
– Flows from higher to lower
elevation
– Can have tributaries
2. Continental Ice Sheet: mass of ice covering a large area of land (over 50,000 km2)
– Associated with continental
glaciation
– Only Greenland
& Antarctica today
– Flows outward from a central high |
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Term
Zone of Accumulation
Zone of Ablation |
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Definition
• Zone of accumulation: perennial snow cover
• Zone of ablation: where ice is lost or ablated
– Positive budgets: advancing glaciers
– Negative budgets: retreating glaciers |
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Term
| • Be able to explain glacial movement—in terms of zone of ablation, zone of accumulation, why glaciers flow downhill. |
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Definition
• Move downslope under the force of gravity
– Rate few mm to 15 m/day
• Base moves by sliding, then layer of plastic
flow, then upper rigid layer
• Moves faster:
–Warmer climate
– Steeper gradient
– In center (away from friction) |
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Term
|
Definition
• Crevasses: tensional
fissures due to
cracking of rigid layer
– Occur in steep
portion or around corners |
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Term
| • How do glaciers erode bedrock? |
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Definition
• Plucking of rock fragments and
abrasion as they are dragged along
– Grooves, striations, polish on rock surface |
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Term
| What are U-shaped valleys, hanging glaciers, and horns? |
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Definition
U-shaped valleys- In geology, a valley or dale is a depression with predominant extent in one direction.
Hanging glaciers- a valley or dale is a depression with predominant extent in one direction.
• Horns – Sharp peaks remaining after
glaciers cut back into 3+ sides |
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Term
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Definition
• Erratics: ice-transported
boulders
• Moraine: body of
unsorted, unlayered sediment left after glacier recedes |
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Term
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Definition
| • Outwash deposits: material deposited by debris laden meltwater |
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Term
| • What types of glaciers occur in Antarctica? How do continental glaciers flow? |
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Definition
• Ice flows away from central high toward edges
• Antarctica = 2 ice sheets
– Ablation from calving
or evaporation
– Thickest part: 4.8 km
(2.87 mi)
• Move by basal sliding
of on thin film of liquid water |
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Term
| • What is the evidence of the Pleistocene glaciations noted by Louis Agassiz? |
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Definition
Theory of glacial ages
– During colder climates in the past much more of the land surface was glaciated than today
– Principle of uniformitarianism to explain landforms in Europe and N. Am |
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Term
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Definition
Wisconsian Glaciation
– Peak ~18,000 years ago,
ended 10,000 ya
– Well preserved, not much
eroded |
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Term
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Definition
Wisconsian Glaciation
– Peak ~18,000 years ago,
ended 10,000 ya
– Well preserved, not much
eroded |
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Term
| What were the direct effects of the Pleistocene glaciations? What is an indirect effect? |
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Definition
Direct effects of past
glaciations
• Scouring of Canadian shield
• Gouging of lake basins
• Loess deposits across
midwest
• Moraines, erratics
• Enhanced alpine glaciation.
• Change in river drainage patterns.
Indirect effects of past glaciations
• Isostatic rebound |
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Term
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Definition
• So…if it’s already getting warmer from natural
causes, what’s the big deal?
Anthropogenically caused
warming!!!! |
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Term
| • What are some of the direct changes that have been observed in the Earth system related to climate change? |
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Definition
Warming of the climate is unequivocal
Numerous long-term changes in climate
observed at continental, regional, and
ocean basin scales
Some aspects of climate have not been
observed to change.
Gobal mean
temperature
Global average
sea level
Northern hemisphere
Snow cove |
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Term
| What is going on (in general terms) with global mean temperature, ocean temperature, troposphere (atmosphere). |
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Definition
1. Warming everywhere at surface except Eastern
Pacific, Southern Ocean, and parts of Antarctica.
2 L d i i ifi tl f t th t 20
Annual Trend 1979 to 2005
2. Land warming significantly faster than oceans over past years.
3. Mid-troposphere warming consistent with that of surface. |
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Term
| global circulation patterns, and precipitation patterns? |
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Definition
• Climate change is affecting
storm tracks,winds and temperature patterns.
Precipitation (rain & snow) is variable—
but there is evidence for systematic change.
Precip has increased in eastern N and S America, N Europe, N
and Central Asia—and decreased in Sahel, Mediterranean, S. Africa, parts of S. Asia.
Proportion of heavy rainfalls: increasing in most land areas.
Drought is increasing most places
Mainly decrease in rain
over land in tropics and
subtropics, but enhanced
by increased atmospheric
demand with warming. |
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Term
| • What is happening to snow cover, sea ice, glaciers, and ice sheets globally? |
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Definition
Snow cover and Arctic sea ice are
decreasing.
Changes in ice sheets
• Greenland ice sheet shrunk from 1993-2003 (99%
confidence)
• Antarctic ice sheet also lost mass, but larger uncertainties
Spring snow cover
shows 5% stepwise
drop during 1980s
Arctic sea ice
area decreased by
2.7% per decade
(Summer:-7.4%/decade)
Glaciers and frozen ground are receding
Glaciers and frozen ground are receding
Area of seasonally frozen
Increased ground in NH has decreased
by 7% from 1901 to 2002
Glacier retreat
since the early 1990s. |
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Term
| • What percent of the increased heat is being taken up by the oceans? |
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Definition
| • Oceans absorbed >80% of heat added |
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Term
Some aspects of climate have not
been observed to change: |
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Definition
•Tornadoes
•Dust-storms
•Hail
•Lightning
•Antarctic sea ice |
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Term
| • Is the present climate unusual for the past 1300 years? |
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Definition
Warmth of the last half century is unusual in at least the previous 1300 years
Last time the polar regions were
significantly warmer than present for an
extended period (about 125,000 years
ago), reductions in polar ice volume led
to 4 to 6 meters of sea level rise. |
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Term
| • What are the primary greenhouse gases of concern? How does the greenhouse effect work? Has the amount of these gases been this high in the past 650,000 years? Can the amount of greenhouse gases in the atmosphere be explained by natural causes? |
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Definition
CO CH d N O C t ti
Change
CO2, CH4 and N2O Concentrations
- far exceed pre-industrial values
- increased markedly since 1750
due to human activities
Relatively little variation before
the industrial era.
The atmospheric concentration of CO2 and CH4 in 2005
exceeds by far the natural range of the last 650,000 years. |
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Term
| • What has been the net effect of humans on the climate system? |
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Definition
• Net effect of human activities is now
quantified and known to cause a warming at the Earth’s surface (~ +1.6° since 1750) |
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Term
| • Which areas of the globe are likely to experience stronger warming? Why? Which areas are likely to experience less warming, why? |
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Definition
Projected warming
century
Climate in 21st expected to be greatest over land and at most high northern latitudes and least over the Southern Ocean and parts of the North Atlantic Ocean. |
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Term
| • Which areas are likely to experience greater/less precipitation? |
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Definition
Precipitation increases very likely (>90% prob) in high
latitudes
Decreases likely in most subtropical land regions |
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Term
| • What are some ways you can help reduce your personal contribution to climate change? |
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Definition
• Reduce your personal carbon footprint
– Recycle
– Conserve water
– Conserve electricity: Raise/lower your
thermostat; compact flourescent light bubls
– Compost
– Carpool or ride a bike |
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Term
| • What are some key outreach and education methods available to you? |
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Definition
• Education and Outreach
– Ask your friends and family to conserve resources
– Let others know it’s not a political issue, it’s a
scientific problem
– Write to your elected officials
– Elect environmentally conscientious politicians |
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Term
| • What are the 3 main types of geologic resources? |
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Definition
Energy
Metals
Non-Metallic Resources |
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Term
| • Explain the difference between resources and reserves. |
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Definition
• Resources - the total amount of geologic resources
in ALL deposits, discovered and undiscovered
– Is a static amount (ex. lifetime income)
• Reserves – amount of a resource that can be
extracted economically
under present conditions
– Amount changes
frequently (ex. Savings
account) |
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Term
| • Where does most US energy come from? Where does most of your energy in Athens come from? |
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Definition
• USA energy sources in 2001:
– 41% oil
– 25% natural gas
– 23% coal
– 12% nuclear and hydroelectic (combined)
=88% from fossil fuels!
Athens=Coal |
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Term
|
Definition
• Result from organic rich, shallow marine or
deltaic deposits
– Nutrient traps
• Requires specific combination of
geologic events to form
– Heating of sediments, microbial action,
burial
– Petroleum window: Burial
from 2,300 to 4,600 m
(7,500-15,000 ft)
– Deeper: petroleum breaks
down into natural gas |
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Term
| What is a source rock vs. reservoir rock? |
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Definition
• Occur in underground pools
Requires:
1. A source rock: rich in organic matter
2. A reservoir rock: in which it can be stored and
transmitted
– High porosity and permeability
– Sandstone or limestone |
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Term
| • What is a structural trap and why is it important? Be able to use this concept to predict where oil may occur. |
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Definition
3. A structural trap: place where impermeable rock prevents upward percolation.
• Anticlines
• Faults
• Seals:
– Clay
– Shale
– Salt dome |
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Term
| • How is petroleum recovered, and what are some negative side effects of petroleum? |
|
Definition
• Drill down
• Pump out oil
– Increase water pressure or steam
• Refine petroleum from crude oil
– Separate into natural gas, gasoline,
kerosene, etc.
• Form petrochemicals
– Dyes, fertilizer, medicine, synthetic
fiber, plastics, etc.
• Environmental effects:
– Salty brine: surface wells pollute water
– Oil spills from broken pipelines
– Tanker spillage at sea
– Oil slicks from offshore platforms
– Subsidence of land surface
– Air pollution from refining and burning |
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Term
| • What is the status of our petroleum reserves? |
|
Definition
• Reserves: ~1,000 billion barrels
– Current usage: 24 bbl/year
=> Only 30-40 years of reserves left!
• More oil exists underground, but only 30-40%
can be extracted
• IN THE USA, annual consumption is 6.3 bbl
– 29% of world consumption by 6% of its pop’n!
(Side note: ANWR only ~2 bbl = 3-4 months)
– Only 25 yrs of reserves and resources left in US
– Natural gas estimates ~30 years |
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Term
| • How does coal form? Why are there different types of coal, why does it matter? |
|
Definition
• Forms from shallow burial
and compaction of peat
– Incompletely decayed plant
material.
• 23% of US energy (90% in
1900)
– 88% of coal used for electricity
generation.
Types of Coal
• Lignite (brown coal)
– 30% Carbon
– Soft and crumbly
• Sub-bituminous and Bituminous
coal (soft coal)
– 40-80% Carbon
– Black and dusty, burns with smoky
flame
– Commonly strip-mined
• Anthracite (hard coal)
– 85-98% carbon
– Shiny and dust-free, burns with
smokeless flame
– Low-level metamorphic rock |
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Term
| • How is coal recovered, and what are some negative side effects of coal? |
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Definition
• Deep mining: 60% recovery
• Strip mining: 80-90%
recovery
• Environmental issues:
– Lower water table
– Acid-mine drainage
– Destroy entire landscapes
– Health concerns for miners!
– Air pollution (VERY BAD) |
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|
Term
| • How is uranium useful for fuel? What European country uses a lot of it? What Middle Eastern country claims they want to develop it too? |
|
Definition
• Used to power nuclear
reactions
– Accounts for 9% of U.S.
energy production
– 75% in France
• Mined from sandstone in
NM, UT, CO, WY
• Create radioactive
waste as by-product
– Incredible storage
problem!
• 70 years of reserves. |
|
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Term
| • What is the status of our coal reserves? |
|
Definition
• USA (~25% of world’s coal supply)
– Resources 1,700 billion tons
– Reserves 265 tons (13% of resources)
• Mine about 1 billion tons/yr
– Use 0.9, export 0.1
• At CURRENT USAGE RATES, could last 250
years
– Likely much less than that! |
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Term
| • What are some renewable energy resources? |
|
Definition
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