Geology 141
Name
Fall, 2004
3:30 p.m.
17 December, 2004
GE141: Physical Processes
Of Planet Earth
Final Examination
INSTRUCTIONS: PLEASE read these instructions and questions CAREFULLY
and completely. If you do not understand a question as it appears on the exam,
PLEASE ASK FOR CLARIFICATION!! It is to YOUR benefit to do so. This
examination is worth 250 points, or 25% of your overall semester grade. Exams will
be graded as quickly as possible; your individual point total will be entered on the last
page to ensure that only you know how well you did on the exam, unless you choose to
divulge that information to others.
Please respond to each question in the most appropriate fashion. Please make your
responses concise and to the point, but thorough; use sketch diagrams any place you
believe that they may help explain your response. There should be ample space
provided for an adequate response to each question; PLEASE RESTRICT YOUR
RESPONSES TO THE SPACE PROVIDED. PLEASE ALSO write legibly; I
CANNOT give any credit for responses I can't read! The number of points for each
question is indicated in parentheses after the question.
PLEASE NOTE: After exams are graded, I will return your exam
ONLY to you. It will not be released to friends, roommates,
your lab partner, or anyone else. This is to ensure YOUR
security and confidentiality.
EXAMS MAY BE PICKED UP
DIRECTLY FROM ME ANY TIME DURING JANPLAN. If you'd like yours mailed
back to you, please enter your mailing address here:
"You must be the change you wish to see in the world."
- Mohandas Gandhi
Geology 141: Fall, 2004
Lecture Final Examination
... Page 2 ...
( PLEASE remember that, as promised on the syllabus, I WILL
deduct a point each time I see "volcanoe" or
"techtonic!" )
1. What are the four criteria that a substance must meet to be considered a mineral? (5
points: 2-1-1-1)
1.
2.
3.
4
2. What are the three major rock groups, and what defines each group? (10 points)
1.
2.
3.
3. Match each of the respective volcanic rocks with its corresponding plutonic igneous rock,
derived from the same magma type, by drawing a line between them (3 points)
basalt
granite
andesite
gabbro
rhyolite
diorite
Geology 141: Fall, 2004
Lecture Final Examination
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4. You have been hiking in eastern California and encountered a rhyolite that showed clear
evidence it had flowed in a very fluid fashion. However, you know that a rhyolitic lava
SHOULD be very viscous. Since there's no questioning the chemical composition of the
rock (you aced your GE141 lab final and know your rocks!), identify one of the two other
factors that could have changed, and how it changed, in order to have allowed the lava to
flow so readily. (2 points)
5. What are three lines of evidence other than the apparent fit of continental margins that
support the theory of plate tectonics and continental drift? HOW does each line of
evidence support this theory? (20 points)
A.
B.
C.
Geology 141: Fall, 2004
Lecture Final Examination
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6. Why are the Hawai'ian Islands NOT an island arc system? (10 points)
7. What are the five major factors that are critical to the development of soils?
(5 points)
1.
2.
3.
4.
5.
8. What is the critical difference between weathering and erosion ? ( 5 points)
Geology 141: Fall, 2004
Lecture Final Examination
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9. What geologic process yields all the plant nutrients to be found in the soils, except for
nitrogen? (5 points)
10. Identify three common cements that occur in sedimentary rocks.
(5 points: 2-2-1)
11. What is the source for these cements that hold sedimentary rocks together?
(5 points)
12. Two non-clastic sedimentary rocks are of particular importance and derived from the
remains of organisms, hence are fairly uniform in chemistry. What ARE these two
rocks, and what is one group of organisms whose remains can be recrystallized and/or
cemented together to form each of them? (5 points: 2-1-1-1)
rock
organism
Mostly SiO2
.
Mostly CaCO3
.
13. We discussed two major techniques of radiometric age determinations in class - the two
principal means by which geologists (and archeologists) can determine the age of
Geology 141: Fall, 2004
Lecture Final Examination
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materials, in years. What ARE those techniques, WHAT can be dated by each, and over
what time range are they applicable? (10 points)
A.
B.
14. Describe (don't just name them!) three metamorphic processes - three ways that
rocks can be metamorphosed into other rock types. (10 points)
1.
2.
3.
15. While driving cross-country through the easternmost Rockies in central
Geology 141: Fall, 2004
Lecture Final Examination
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Montana last summer, you saw the above section of rock exposed in a canyon wall. You
now can appreciate what must have happened, because you recognize and understand
the significance of what you saw. (A) What geologic structural feature is depicted here,
and (B) what kind of stress would have produced this deformation in the rocks? (10
points)
16. Identify ANYPLACE ELSE in the world where you would expect to see a similar feature.
(5 points)
17. What was the first major line of evidence earthquakes yielded that indicated that the
interior of the Earth was at least partially liquid? (5 points)
18. Of what material are the inner and outer core of the Earth comprised? (5 points: 3-2)
Geology 141: Fall, 2004
Lecture Final Examination
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Outer core:
Inner core:
19. What are seismic gaps and why are they important? (10 points)
20. What is surface creep as a mass-wasting phenomenon, how does it occur (i.e., what
are the processes that create it) on a hillside, and what would be a good indication that it
was indeed taking place on a slope? (10 points)
21. What are three ways that streams carry sediments, and what is typically carried in each
of these three parts of the total sediment load? (10 points)
A.
Geology 141: Fall, 2004
Lecture Final Examination
... Page 9 ...
B.
C.
22. What is the principal means by which sediment is introduced into streams?
(5 points)
23.
Based on the flood-frequency graph shown above, how often would you anticipate seeing
a flood on this particular river that would exceed 100,000 cubic feet per second in total
discharge? (5 points)
24. What are the two principal mechanisms by which glaciers actually move downhill? (5
points: 3-2)
(A)
Geology 141: Fall, 2004
Lecture Final Examination
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(B)
25. Glaciers exist because more snow falls in an area than melts, year after year. Identify
two contributing geologic factors that can help to initiate glaciation in any given area,
over any time scale. (5 points: 3-2)
1.
2.
26. Identify two INdirect effects that glaciers have on the environment (i.e., effects that
take place outside the area where the glaciers themselves exist). (5 points: 3-2)
1.
2.
27. When you drill or dig a well, you're tapping into groundwater. Where does this water
COME FROM? (5 points)
28. Explain how orographic ("rain shadow") deserts, such as that in the American West,
come into existence. ("Why isn't Nevada as lush and green as Virginia?") (10 points)
Geology 141: Fall, 2004
Lecture Final Examination
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29. How are waves created on the ocean or any large body of water? What are the three
major factors that are ultimately responsible for the formation of waves? (10 points)
Geology 141: Fall, 2004
Lecture Final Examination
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30. What is THE dominant geologic process active on cliffed coasts? (5 points)
31. What is longshore drift, and why is it of any significance? (5 points)
32. Why are most mining districts (for other than coal or iron ore) in the world found in
areas that are now, or once were, plate margins? What aspect of major ore formation
concentrates many mineral resources in these kinds of geologic environments? (10
points)
33. What specific geologic resource is, in total dollar value production on an annual basis,
the most valuable commodity produced in 38 of the 50 states of the U.S.? (5 points)
Geology 141: Fall, 2004
BONUS
Lecture Final Examination
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QUESTIONS ! (for extra credit, if you want to try for
it!)
[ No penalty if you leave this page blank. ]
(A) Some years back, I was asked to testify before the Maine State Board of Environmental
protection relating to a proposed sand and gravel development in Belgrade, on another
segment of the same esker you visited on the field trip. The wetlands scientist hired by
the gravel company presented the following diagram as part of his explanation that
they were only planning to remove the topmost
seventy feet of gravel down from the surface, and therefore would not impact the water
table and the water supplies of everyone living in the area. For up to ten (10) bonus
points, what is fundamentally wrong with his diagram, that made all his other
arguments about environmental impacts immediately suspect? (feel free to draw on the
diagram if you want)
(B) What are karst environments, and what kind of rock almost always underlies karst
environments, such as those in Puerto Rico, Florida and the Yucatán Peninsula? (5
points)
Geology 141: Fall, 2004
Lecture Final Examination
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34. On the maps on the following page (the maps are printed back-to-back), locate precisely each of
the following localities or features. FOR SMALL FEATURES OR LOCALITIES, use a
sharp arrow drawn from your label to the feature, SO YOUR LABEL CAN BE EASILY
READ and there can be no doubt about what you are labeling. PLEASE remember that IT IS
TO YOUR BENEFIT that your label is clear enough that there is NO question as to your
meaning or intent (OR spelling)! (20 points, 1 point each)
And YES, all labels must be correctly spelled for credit!
[ Since all you have to do is copy the name from the list below! ]
On the map of the U.S. & Canada:
On the map of the world:
the Chesapeake Bay
Hudson's Bay
Lake Ontario
Alaska
British Columbia
New Guinea
Idaho
Cuba
New Mexico
Nile River
Virginia
Red Sea
Minnesota
Java
Connecticut
Tierra del Fuego
Ohio
Ganges River
Gulf of California
Kuril Islands
Grade on exam:
out of 250 possible.
Total for Course:
out of 1000 possible.
Course Grade:
EARTH TREMORS FELT IN MISSOURI
The quake last night was nothing personal,
you told me this morning. I think one always wonders,
unless, of course, something is visible: tremors
that take us, private and willy-nilly, are usual.
But the earth said last night that what I feel,
you feel; what secretly moves you, moves me.
One small, sensuous catastrophe
makes inkings letters, spelled in a wordly tremble.
The earth, with others on it, turns in its course
as we turn toward each other, less than ourselves, gross,
mindless, more than we were. Pebbles, we swell
to planets, nearing the universal roll,
in our conceit even comprehending the sun,
whose bright ordeal leaves cool men woebegone.
- Mona Van Duyn (1921-2004)
U. S. Poet Laureate, 1992-1993