OCG123, Spring 2001
Final exam, Tuesday 8 May 2001
Chapters 1–11
Definitions (2 points each; 20
points total)
1. Primary producer.
2. Impact degassing.
3. Hydrothermal vents.
4. Stratosphere.
5. Logistic growth.
6. K-T boundary.
7. Positive feedback.
8. Troposphere.
9. Moraine.
10. Perihelion.
Short answers (3 points each; 30
points total)
1. What happens to the 18O/16O
ratio in seawater during glacial periods, and why?
2. Give three general geological
indicators of Pleistocene glaciation.
3. What is the most likely cause of the
rise of oxygen in the atmosphere 2.2 billion years ago?
4. How could the building blocks of life
on earth have been formed in outer space and transported here?
5. What happened to the earth when the K-T
meteorite hit?
6. What is the inverse square law, and why
is it so important? How can you derive it very simply?
7. Why are O2 and N2
not greenhouse gases?
8. How is excess heat from the tropics
transported to the polar regions?
9. What is the Ekman spiral?
10. What drives plate tectonics?
Longer answers (5 points each;
30 points total)
1. Explain how CO2 weathers
crustal rock.
2. Explain the thermohaline “conveyor
belt” of three dimensional circulation in the ocean and the forces that make
it go. Use a diagram if necessary.
3. Explain how the northeast trade winds
are formed as part of the three-celled hemispheric circulation pattern of the
atmosphere. Use a diagram if necessary.
4. Explain how banded iron formations are
deposited and how this process can help us determine the time when atmospheric
oxygen rose.
5. How has the pattern of mass extinctions
on earth (intensity and frequency) varied over time, and why?
6. Explain how the comings and goings of
ice ages can be recorded in carbonate sediments of the North Atlantic. What do
these records tell us of glaciations over the past 2–3 million years?
Problems
and discussion questions (10 points each; 20 points total)
1. Explain the earth’s three major
orbital parameters, how they vary with time, and what their characteristics
periods are. Use diagrams if you wish. Which of these is amplified to become the
dominant period (cycling time) in the recent ice ages? Use a diagram to show by
how much it is amplified relative to the other cycles. What is the accepted
mechanism for amplifying this period?
2. Explain the basic forces that have
controlled global change on the earth, what the nature of those changes were and
are, and the ways that the forces and the changes may be currently affected by
humankind. How does your answer to this question differ from the way you would
have answered it before you took this class?
Optional extra credit (10
points)
What about this class did you find: (a)
most valuable, (b) least valuable; (c) hardest; and (d) easiest? Are there any
ways in which you would adjust it to make it more valuable to next year’s
students?