Chapter 12: Climate and Glaciation
• Lonnie Thompson trekks to Himalaya, the Andes, and beyond to study ice.
Essential Earth 1e © 2008 by W. H. Freeman and Company
•Jordan,
Do The
you
know why ? What is he studying ?
Chapter 10: Climate and Glaciation
• No scientist has taken
bigger risks above 18000
ft, risking blood clots,
temporary blindness,
frostbite, and hurricaneforce winds.
• Risks to gather
measurements and help
us understand current
climate trends.
• Lonnie Thompson reconstructed a meticulous calendar of
temperatures and dates from isotope measurements in ice.
• He found that the Earth's frozen ice stores a history of climate
changes as far back as 750,000 yrs.
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The Earth's Climate
• What is climate ?
Climate is described by the average weather conditions at a point
on the Earth's surface daily, yearly or longer.
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The Earth's Climate
• The climate includes many components of the Earth's system and
interactions between them.
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The Earth's Climate
• The atmosphere is layered with different temperature values in each
• Temperatures in other Earth systems such as ocean water,
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biosphere,
lithosphere, & crysophere all contribute to an average
Glaciers
• The cryosphere comprises all of the ice on the Earth.
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Glaciers
• Most of the Earth's ice is found in Antarctic continental glacier.
• Where are some other continental glaciers ?
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Glaciers
• Greenland is the second largest
glacier on Earth and with Antarctica
cover 10% of the Earth's land mass.
• These glaciers store 75% of the
world's fresh water.
• While Greenland has 2.6 mill cubic
km of ice, it is dwarfed by Antarctica
which has 30 mill cubic km (90%) of
the Earth's cryosphere.
• Antarctica's ice is ~4000 m thick!
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Glaciers
• Snow melt is the
source of much of the
fresh water in the
hydrosphere.
• Snowfall is 60-70% of
all annual precipitation
which melts in spring
into rivers and streams.
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Glaciers
• The cryosphere
includes sea ice which
grows in volume in the
winter and shrinks in the
summer.
• This satellite picture
(left) shows sea ice
flowing through the
Bering Strait in May
2002.
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Heat flowing out of Earth’s
deep interior is only 0.06 W/m2.
Solar energy input to
Earth’s surface is
342 W/m2.
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Therefore, heat
radiating from Earth
must balance solar
input.
Heat and Radiation from the Sun
• The Earth reflects radiation not absorbed by the atmosphere & surface
• Strong greenhouse gases reflect this radiation back to the Earth and
prevent it from leaving the atmosphere.
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
The Balance of Heat Flow into/out of the Earth
• Water vapor gives positive feedback, that is, it is a greenhouse gas
and its presence prevents escape of the Earth's excess radiation.
• Albedo gives positive feedback. Albedo measures the Sun's
reflected energy from the cryosphere. As the Earths' temp rises, and
glaciers melt, the albedo decreases. This process reduces reflected
radiation escape.
• Radiation damping can give negative feedback. Infrared energy
escape is increased if temperatures rise. This process slows large
temperature fluxuations and keeps the oceans from freezing or
boiling off.
• Plant growth gives negative feedback. Conversion of CO2 into
organic matter reduces greenhouse gasses in the atmosphere and
allows for more escape of radiative energy.
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
What Would our Planet be like Without Greenhouse Gases ?
• The Earth rotates (1 day)
much faster than the Moon (30
days) which evens out its
temperature
• The Moon's temp changes
from 130 C in the day to -170 C
at night! This would be very
uncomfortable!
• The Earth's glaciers increases its albedo to 31% where the Moon's
albedo is only 7%.
• However without any greenhouse gases, the Earth's surface temp
would be very cold, -19 C (-2 F) and would freeze all our oceans.
• Some greenhouse gases are necessary to moderate strong
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fluctuations
in surface temperature from Solar radiation
Local Climate Variations
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Antarctic Ice Sheet
• Today many scientists work to study ice cores in Anarctica
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• Russian scientists at Vostok
station carefully remove an ice core
at 3500m altitude (T is about -55C
!)
• Below inspection of the core is
done in a cold lab.
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Past Glaciation
from Ice Cores
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Climate has been
relatively warm and
stable during the last
10,000 years.
High
Key:
Temperature
CO2
Methane
Thousands of years before present
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Relative carbon dioxide and
methane concentrations
Temperature relative to present climate (°C)
There is a decline in both
temperature and greenhouse
gas concentrations during
glacial periods…
…and a rapid
rise during
deglaciation.
Low
Glacial and Temperature Cycles
• White shows evidence indicating the extent of the Wisconsin
glacier in the Great Lakes during it's maximum about 18000 yrs ago
and was ~3 km thick.
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Human activities release
a total of 7.1 Gt of carbon
into the atmosphere each
year.
New plant growth and
air-sea gas exchange
remove 3.8 Gt/yr,…
ATMOSPHERE
Fossilfuel
burning
(5.3 Gt/yr)
Land-use
change:
deforestation,
agriculture
(1.7 Gt/yr)
Land uptake
By new plant
growth
(1.9 Gt/yr)
Terrestrial biosphere
LAND
Cement production (0.1 Gt/yr)
Fossil
Rock
organic
carbonates
carbon
GEOLOGIC RESERVOIRS
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Ocean uptake
by air-sea gas
exchange
(1.9 Gt/yr)
OCEAN
…yielding a net
atmospheric
increase of
3.3 Gt/yr.
Temperature
CO2
concentration
Years
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CO2 concentration (ppm)
Global temperature anomaly (°C)
A recent warming trend correlates
with the increase in CO2.
CO2 concentration (ppm)
Northern Hemisphere temperature
anomaly (°C)
The 20th-century is clearly
anomalous when compared
with the last millennium.
Temperature
CO2 concentration
Years
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Arctic sea ice 1995-2007
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(National Snow and Ice Data Center, Boulder)
Arctic sea ice 2005-2007
4.3
4.3million
millionsq
sqkm
km
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(National Snow and Ice Data Center, Boulder)
Receding Glacier
South Cascade Glacier, Washington
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Meteorites found in Arctic Glaciers
• The easiest place to locate dark, rocky meteorites is in Antarctic Ice
Sheet
• A small number of meteorites appear to have come from the Moon
and Mars
• Several of these appear to have come from Mars
martian meteorite
lunar
meteorite
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Global Warming
• Global warming is a physical
measurement that the Earth's
surface temperatures are rising
beyond normal fluctuations.
• Global warming can have many
effects on our environment:
- increase atmospheric temperature
- melt glacial ice
- prevent escape of the Sun's excess radiation
- harm habitat environments like polar bears
- create drastic changes in our climate (extreme hot and cold seasons)
- and remove our only evidence of past climate history !
What can we do about this at home ?
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
The Global Energy Challenge
Roel Snieder
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Photo: USFWS/Susanne Miller
Developing countries
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
… and our energy use
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How do Geologist Find Old Glaciers Boundaries ?
Glaciers leave clues ...
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• Glacial striations on a
rock from stones grinding at
the base of a heavy ice sheet
leave these shiny linear
marks on the bedrock below.
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Glacial Characteristics
• Glaciers flow downhill as a solid mass that creates channels, and
walls made of ground up rock debris known as a merraine.
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Erosional Landscapes
• Erosional landforms produced by
valley glaciers include:
– U-shaped valleys
– Hanging valleys
• Smaller tributary glacial valleys
left stranded above more
quickly eroded central valleys
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Erosional Landscapes
U-shaped valleys
Hanging valleys
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Glacial Deposits
• Sediment-laden streams emerging
from ends of glaciers have braided
channel drainage patterns
• Outwash landforms include
drumlins, eskers, kettles and kames
• Drumlins give can tell us what
direction a glacier moved.
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
The History of Energy Consumption
in the US over past 150 yrs
How much oil is available in the world for our use ?
Is it infinite ?
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Peak oil
N.B. based on USGS estimates, these are among the most optimistic
(Energy Information administration)
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Declining production (1)
Production
resource
depleted
Time
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Declining production (2)
Production
production gap!
Time
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Oil Peak, Oil Panic ?
(Study by Amos Nur - Stanford)
U.S., Canada, Japan, Germany, France, Italy, UK, are the bigges
consumers
of© 2008
oilbyreserves
worldwide.
Jordan,
The Essential Earth 1e
W. H. Freeman and Company
Oil Consumption
World wide by country
The US uses more oil than
all other countries combined
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Countries with highest per capita income seeking oil from countri
Jordan, The Essential
Earth oil
1e © 2008
by W. H. Freeman and Company (Saudi Arabia, Iraq, Venezuala).
holding
the
wells/reservoirs
New find in Gulf of Mexico
(Jack No. 2 test well)
• up to 3-15 billion barrels of oil
• US consumption 20 million barrels/day
• 5 months - 2 years
• reservoir is 8 km under sea level
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Non-convenional reserves
(excluding gas and coal)
Produced (gone)
Proved Reserves
Undiscovered(?)
Conventional
(“easy”)
0
EOR
25
1
2
Shale Oil
Unconventional petroleum resources:
(more difficult & dirty, and therefore expen$ive)
50
Years Supply at
2005 Production
0
Extra Heavy Oil
& Tar Sands
3
4
5
6
Trillions of Barrels Recoverable
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
(Courtesy of Joe Stefani)
7
8
9
10
Non-conventional oil
2 tons of tar sands produce 1 barrel of bitumen (~asphalt)
Tar Sand
Heavy
Oil
from National Geographic, June 2004
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Oil
shale
Other Energy Resources
• The metal uranium is used to power nuclear power
generators
– Found with organic matter in sedimentary rocks
– Accounts for 10% of U.S. energy production
– Leaves radioactive waste as by-product
• Hydroelectric power provides about 4%
of U.S. energy needs
– Renewable and non-polluting
• Geothermal power provides about 0.2%
of U.S. energy needs
• Other renewable, non-polluting energy sources are
wave/current power, solar power, wind power, and
hydrogen fuel cells
– As fossil fuel supplies dwindle, these sources become more important
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Other Energy Resources
• The metal uranium is used to power nuclear power
generators
– Found with organic matter in sedimentary rocks
– Accounts for 10% of U.S. energy production
– Leaves radioactive waste as by-product
• Hydroelectric power provides about 4%
of U.S. energy needs
– Renewable and non-polluting
• Geothermal power provides about 0.2%
of U.S. energy needs
• Other renewable, non-polluting energy sources are
wave/current power, solar power, wind power, and
hydrogen fuel cells
– As fossil fuel supplies dwindle, these sources become more important
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
First solar 2 MW array
Ft. Carson, CO
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Research: efficient solar cells
1 mm
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http://gcep.stanford.edu/research/solar.html
Alternative Energy Sources: Wind power
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What can I do as consumer?
Lighting
Transportation
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Appliances
What can I do as citizen?
• Ask: what is our energy
plan?
• Start a discussion in
your community.
• Demand that the United
States becomes a
world-leader in
responsible use of
energy.
z
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
“That
which we are, we shall teach, not voluntarily but involuntarily.” [Emerson]
What can I do as citizen?
• Ask: what is our energy
plan?
• Start a discussion in
your community.
• Demand that the United
States becomes a
world-leader in
responsible use of
energy.
z
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
“That
which we are, we shall teach, not voluntarily but involuntarily.” [Emerson]
Geologic Structures
Chapter 15
San Andreas Fault - Palmdale
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Geologic Structures
Geologic structures tell us about:
- Plate/crust strength and deformation
- Oil and gas reservoirs
- Engineering decisions
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
How Rocks Deform
• Rocks behave as elastic, ductile or brittle materials
depending on:
– rate of stress application
– type of rock
– temperature and pressure
Elastic Deformation:
• If deformed materials return to original
shape after stress removal, they are behaving
elastically
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Ductile Deformation:
• Once the stress exceeds the
elastic limit of a rock,
it deforms permanently
– ductile deformation involves
bending plastically
Brittle Deformation:
– brittle deformation involves fracturing or breaking
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Applied Stress
Stress is force per unit
area
The three basic types of stress are
- compressive
Produces shortening
or flattening
- tensional
Produces stretching
or extension of material
- shear
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Shear Stress
Shear stress: stress that acts parallel to a plane
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Material Strain
• Strain is a change in size
or shape in response to stress
– Geologic structures are
indicative of the type of stress
and its rate of application, as
well the physical properties
of the rocks or sediments
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Structures and Geologic Maps
• Rock structures are determined
on the ground by geologists
observing rock outcrops
– Outcrops are places where bedrock is
exposed at the surface
• Geologic maps use
standardized symbols and
patterns to represent rock
types and geologic structures,
such as tilted beds, joints,
faults and folds
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Orientation of
Geologic Structures
• Geologic structures are most
obvious in deformed sedimentary
rocks
• Tilted beds, joints, and faults are
planar features whose orientation is
described by their strike and dip
– Strike is the compass direction of a line
formed by the intersection of an inclined
plane with a horizontal plane
– Dip is the direction and angle from
horizontal in which a plane is oriented
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Strike and Dip on a Map
Map View
strike
dip
Cross-Section
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Depth
Types of Geologic Structures
• Folds are wavelike bends in
layered rock
– Represent rock strained in a ductile
manner, usually under compression
• The axial plane divides a fold into
its two limbs
– The surface trace of an axial plane is
called the hinge line (or axis) of the fold
• Anticlines are upward-arching
folds, and synclines are
downward-arching folds
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Folding and Age of Layers
Anticlines eroded horizontally
at the surface show oldest ages
in the center line.
Synclines eroded horizontally
at the surface show youngest ages
in the center line (bedding ages
are symmetrically older going
away from center)
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Structural Domes
and Basins
• Domes are structures in
which the beds dip away
from a central point
– Sometimes called doubly
plunging anticlines
• Basins are structures in
which the beds dip
toward a central point
– Sometimes called doubly
plunging synclines
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Fractures in Rock
• Joints - fractures bedrock
along which no movement has
occurred
– Multiple parallel joints are called joint sets
• Faults - fractures in bedrock
along which movement has
occurred
– Considered “active” if movement has occurred
along them within the last 11,000 years
– Categorized by type of movement as dip-slip,
strike-slip, or oblique-slip
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Types of Faults
• Dip-slip faults have movement
parallel to the dip of the fault
plane
– In normal faults, the hanging-wall
block has moved down relative to the
footwall block
– In thrust faults, the hanging-wall block
has moved up relative to the footwall
block
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company
Types of Faults
• Strike-slip faults have movement that
is predominantly horizontal and
parallel to the strike of the fault plane
– A viewer looking across to the other side of a
right-lateral strike-slip fault would observe it
to be offset to their right
– A viewer looking across to the other side of a
left-lateral strike-slip fault would observe it
to be offset to their left
• Oblique-slip faults have movement
with both vertical and horizontal
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Right-lateral San Andreas Fault
Stream Displacement at Wallace Cree
Right lateral or left lateral slip ?
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Geologic Structures
Geologic structures tell us about:
- Plate/crust strength and deformation
- Oil and gas reservoirs
- Engineering decisions
Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company