GEO 302C EXAM 2 Spring 2008
Name_____________________________________
UID______________________________________
You may not refer to any other materials during the exam. For each question (except otherwise
explicitly stated), select the best answer for that question. Read all choices before selecting an answer
and make sure your choice answers the question asked.
Match (one-to-one) the following (1–5) from the list (A–E) below.
C1. Obliquity
E2. Eccentricity
D3. Precession
B4. Aphelion
A5.
Solstices
A. The longest or shortest days of the year
B. The position farthest from the Sun (the “distant pass” position)
C. The tilt of Earth’s axis
D. The shift of the positions of the solstices and equinoxes
with respect to Earth’s eccentric orbit
E. The degree of departure from a perfectly circular orbit
Match (one-to-one) the following names (6–10) from the list (A–E) below.
D6. Laurentide ice sheet
E7.
B8.
Cordilleran ice sheet
Scandinavian ice sheet
A9. Equilibrium line
C10. Permafrost
A. The boundary between the upper area of positive ice mass balance
and the lower area of net loss of ice mass
B. The ice sheet in northern Europe
C. The deep frozen ground caused by the harsh winter cold and
sparse snow cover
D. The ice sheet centered on east-central Canada
E. The ice sheet over the Rockies in the American West
E11. The importance of understanding the past climate and climate change lies in the fact that
A. past variability can show climatic extremes not experienced during recorded history
B. in order to understand the effects of human activity on climate, we must establish what the planet’s
atmosphere and climate was like before human perturbations
C. what happened in the past will probably happen in the future
D. Both A and B
E. All A, B, and C
E12. Which of the following is true about proxy climate data?
a. They can tell us about what Earth’s climate was prior to the invention of instruments.
b. They include sediments, ice, corals, and trees.
c. They are as precise as the modern instruments in measuring climate.
d. All of the above.
e. a and b only.
A13. Tree rings
a. can reveal how climate varied over the last few tens, hundreds, or (in exceptional cases) thousands of
years.
b. are best developed in the tropics where it is pleasantly warm and wet.
c. can tell us about a wide range of past climate conditions including rainbow, salinity, wind direction,
and atmospheric pressure.
d. are a good indicator of how fast the ocean-floor is spreading.
e. are the most important source for pinpointing the past variations of atmospheric carbon dioxide.
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B14. Which of the following is true in describing ocean sediments?
a. Ocean sediments have the best resolution to describe how El Niño has evolved over tens of millions of
years.
b. Ocean sediments contain key indicators of past glaciations: ice-rafted debris, δ18O records, and δ13C
records.
c. Ocean sediments are available in the northern Atlantic Ocean only.
d. All of the above.
e. None of the above.
E15. Which of the following is true in describing ice cores?
a. Ice cores contain important greenhouse gases signals unavailable from other proxy sources.
b. Ice cores can resolve climate variability on a yearly basis.
c. Cores from present-day ice sheets date back tens to hundreds of thousands of years.
d. Ice core measurements of carbon dioxide and methane over the last few centuries merge very well
with instrumental measurements made since the late 20th century.
e. All of the above.
B16. In climate research, the direct measurement of air temperature is made by placing a
thermometer under sunlight.
A. True
B. False
E17. Which of the following is in the correct sequence from long to short term effects on climate?
A. eccentricity – plate tectonics – El Niño – seasonal changes in monsoon intensity
B. plate tectonics – Earth’s orbital parameters – El Niño – seasonal changes in insolation
C. plate tectonics – El Niño – precession – seasonal changes in insolation
D. eccentricity – obliquity – precession – El Niño
E. both B and D are correct
E18. The Milankovitch theory explains glacial and interglacial cycles during the current Icehouse era.
Which of the following is NOT true about these cycles?
a. In the northern hemisphere the ice sheet cycles respond to and lag the summer insolation cycles.
b. One part of the cycle is the change in the tilt of the Earth about every 41,000 years.
c. One part of the cycle is the change in the positions of solstices and equinoxes in relation to
Earth’s orbit over time scales of 23,000 years.
d. The cycles have been supported by the trends of atmospheric CO2 and CH4 as recorded in the
Antarctic ice core.
e. One part of the cycle is the wobbling of the spin axis about every 100,000 years.
B19. During the Last Glacial Maximum,
A. the atmospheric CO2 and CH4 values were higher than present
B. continental ice sheets existed in northern United States, Canada, and northern Europe
C. forests in Europe and Asia covered larger areas than today
D. the sea level was higher than present
E. all of the above
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D20. Which of the following statement is not true about the ice ages?
A. During ice ages it was globally windier as shown by the increased accumulation of dust in ocean
sediments.
B. Earth’s climate tends to drift slowly into ice ages which are rapidly terminated by sudden warming.
C. Each time the Earth was locked in ice, the level of the oceans dropped from their present levels by
more than 100 meters.
D. At the peak of ice ages, the forest-covered areas increased in size and the tundra biome was smaller
in area.
E. The size of ice sheets has a delayed response to summer insolation by thousands of years.
B21. Which of the following processes removes CO2 from the atmosphere?
a. fast seafloor spreading
b. chemical weathering
c. volcanic eruptions
d. continental collision
e. dinosaurs roaming
E22. The evidence that the world was warmer 100 Myr ago than today includes
a. fossils of broad-leafed evergreen trees that were found poleward of the Arctic and Antarctic
circles
b. fossils of warm-adapted animals (dinosaurs) that were found at high-latitudes
c. isotopes from ocean sediments
d. extension of coral reefs to higher latitudes
e. all of the above
D23. Which of the following is not correct in describing the world by 100 Myr ago
a. sea level was 100-200 meters higher than today because of no polar ice caps
b. temperatures were warmer than they are today at all latitudes, but especially in polar regions
c. the positions and sizes of land/oceans were different from today
d. atmospheric CO2 concentration was similar to today’s values
e. Texas was mostly under water
C24. The temperature trends in the last 55 Myr can be estimated from
a. the outline shapes of fossil leaves
b. measurement of δ18O in ocean sediments
c. both a and b
E25. The possible causes of Earth’s cooling in the last 55 Myr are
a. decrease in ocean-floor spreading rate
b. uplift weathering
c. ocean heat transport through gateways
d. ice-albedo feedbacks
e. all of the above
A26. What controls the size of ice sheets?
a. summer insolation
b. winter insolation
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E27. Oxygen isotopic ratios (δ18O) from ocean water recorded in foraminifera shells can tell us
a. the volume of continental ice sheets
b. the temperature of ocean water in which the shells form
c. wind directions
d. the ozone layer
e. both a and b
A28. The _____ isotope is most predominate of all the oxygen present.
a. 16O
b. 18O
C29. If you take samples today from the following places, which place has more negative δ18O (or
16
O-enriched)?
a. tropical surface ocean
b. tropical deep ocean
c. polar ice sheets
d. midlatitude rivers
A30. If measurements of δ18O from ocean sediments show a long-term trend toward more positive
values (or 16O-depleted), this tells us a long-term ______ trend.
a. cooling
b. warming
c. neutral
A31. The _____ isotope is most predominate of all the carbon present.
a. 12C
b. 13C
A32. During photosynthesis, the ______ isotope is incorporated in living tissues more easily.
a. 12C
b. 13C
A33. In today’s world, which of the following has more negative δ13C (or 12C-enriched)?
a. all land vegetation plants
b. all the ocean waters
C34. Which of the following has the most carbon?
a. the atmosphere
b. vegetation
c. the oceans
D35. Where did the carbon removed from the atmosphere go during glaciations?
a. vegetation
b. ice sheets
c. surface oceans
d. deep oceans
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A36. A major player in orbital-scale climate changes is changes in ________ rather than _______ ice
sheets.
A. Northern Hemisphere, Antarctic
B. Antarctic, Northern Hemisphere
B37. Earth has seasons primarily because of
A. latitude
B. tilt
C. longitude
D. ice sheets
E. oceans
A38. The delay in bedrock response to ice loading acts as _________ to ice volume.
A. a positive feedback
B. a negative feedback
C. nothing happens
A39. When is Earth closest to the Sun in its present-day orbit?
A. January 3
B. July 4
C. March 20
D. September 22
B40. Which latitudes are most affected by changes in the tilt of Earth’s axis?
a. tropics
b. higher midlatitudes
C41. What features of the ice core CH4 signal suggest a link to tropical monsoons?
a. cycles of 100,000 years
b. cycles of 41,000 years
c. cycles of 23,000 years
B42. The air bubbles in ice cores are ______ the ice in which they are sealed.
a. older than
b. younger than
c. as old as
B43. A higher count of pollen from prairie grasses and herbs in lake sediments indicates a _____
climate, while a higher count of pollen from trees suggests a _______ climate.
a. wetter, drier
b. drier, wetter
A44. A higher count of spruce pollen in lake sediments indicates a _____ climate, while a higher
count of oak pollen suggests a ______ climate.
a. colder, warmer
b. warmer, colder
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A45.
The glacial climate of the southwestern United States was _______ than the climate there
today.
a. wetter
b. drier
A46.
During the Last Glacial Maximum, summer insolation is not significantly different from that
today.
a. True
b. False
A47.
As the Earth’s tilt increases, polar regions receive _____ radiation in summer.
a. more
b. less
c. the same amount of
A48.
The cyclic changes in orbital insolation are important as the ultimate driver of changes in
monsoons, ice sheets, and greenhouse gases over the past 500,000 years.
a. True
b. False
A49.
The δ13C signal became more negative each time the δ18O signal became more positive.
a. True
b. False
E50.
My TA for this course is
a. Amanda Su
b. Kathy Austin
c. Anne Travis
d. Christie Liang
e. None of the above
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