Download First Hour Exam, Fall, 2015

Geology 141(A)
Name
Autumn, 2015
7 October, 2015
GE141(A): Earth and Environment
First Hour
Examination
INSTRUCTIONS :
PLEASE read the 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 125 points, or 12.5% 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.
"We live in a society exquisitely dependent on science and
technology, in which hardly anyone knows anything about
science and technology.... This is a prescription for disaster. We
might get away with it for a while, but sooner or later this
combustible mixture of ignorance and power is going to blow up
in our faces."
- Carl Sagan, Astrophysicist (1934-1996)
Geology 141(A): Fall, 2015
First Hour Examination
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Section I: Multiple-choice. Please read each question and possible answer
carefully, and circle the letter of the correct or best response to each question.
Do NOT under any circumstances circle the entire response or write the answer in the margin!
Doing so suggests to me that you are attempting to assist someone else on the
exam, which is definitely a bad idea! Each question is worth 4 points; the section
as a whole is worth 80 points of the 125 for the exam.
1. The "Big Bang" that produced the entire Universe as we know it occurred about
a. 13.5-14.0 billion years ago
c. 4.6-4.7 billion years ago
b. 13.5-14.0 million years ago
d. 4.6-4.7 million years ago
2. Our planet Earth, and the rest of our Solar System, are believed by scientists to have
formed approximately
a. 13.5-14.0 billion years ago
c. 4.6-4.7 billion years ago
b. 13.5-14.0 million years ago
d. 4.6-4.7 million years ago
3. The strongest evidence that our solar system, including Earth, was derived from the
debris produced by an exploding star (supernova) is found in
a. the fact that the Earth has a core consisting mostly of iron.
b. the abundance of transferric elements on Earth, those above iron in the periodic
table.
c. the fact that the Earth is the "water planet" with abundant oxygen.
d. the fact our solar system is the only one that scientists know exists anywhere in our
part of the Milky Way Galaxy.
4. The most abundant element by weight in the Earth as a whole is
a. oxygen
b. silicon
c. sulfur
d. iron
e. lead
f. sodium
5. The most abundant element by weight in the Earth's crust is
a. oxygen
b. silicon
c. sulfur
d. iron
e. lead
f. sodium
6. The most common mineral group in the crust, comprising some 95% of the crust, is
the
a. oxides
b. native elements
c. sulfides
d. carbonates
e. silicates
7. The other mineral group that is more important for its bulk (3%) in the crust, rather
than its economic significance, is the
a. oxides
b. native elements
c. sulfides
d. carbonates
e. silicates
8. New oceanic crust is being created by
a. divergence along the mid-oceanic rise and ridge system (MORRS).
b. volcanism on countless thousands of mantle plumes, or "hot spots," that underlie
all the world's ocean floor.
c. convergence of continents along subduction zones.
d. sediments that wash off the continents, to fill in the ocean basins, creating new
crust beneath them.
9. Typical island arc systems include all of the following except
a. the Kuril Islands
c. the Aleutian Islands
e. the Philippine Islands
b. the Hawaiian Islands
d. Java and Sumatra
10. Oceanic crust is being subducted along a continental margin in all of the following
places except
a. the western coast of South America.
d. the southern coast of Kamchatka
b. the western coast of Central America
e. the western coast of Africa
c. the southern coast of Alaska
11. The rates of movement of tectonic plates are typically measured in
a. millimeters per year
c. meters per year
e. kilometers per year
b. centimeters per year
d. meters per day
Geology 141(A): Fall, 2015
First Hour Examination
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12. Stratovolcanoes have steep sides because
a. they are made up of plutonic rocks that have been "pushed up" from beneath.
b. they are comprised of interlayered flows and pyroclastic debris from viscous
eruptions.
c. they are the product of very low-viscosity eruptions of basaltic lavas.
d. they are the products of fissure eruptions, such as those in Hawaii and Iceland.
13. Magmas are
a. molten rock
c. solid rocks thrown out of volcanoes
b. small volcanoes
d. deep areas in the ocean above subduction zones
14. The minerals at the top of Bowen's Reaction Series
a. have high melting temperatures.
b. have low silica content.
c. are usually dark in color.
d. are the principal minerals in basalt and gabbro.
e. all of the above.
15. Most plutonic rocks tend to be intermediate or felsic in character. Dikes and sills,
however, are often mafic. This is because
a. mafic magmas are always more likely to crystallize underground.
b. mafic magmas are normally more viscous than magmas with more silica in them.
c. mafic magmas are usually going to crystallize as porphyritic rocks.
d. mafic magmas are normally less viscous than magmas with more silica in them.
16. The difference between stocks and batholiths in plutonic rocks is that
a. stocks are usually mafic, batholiths are usually felsic.
b. stocks are usually felsic, but batholiths are usually mafic.
c. stocks are tabular, parallel-sided bodies, whereas batholiths are irregular in form.
d. stocks are smaller than 100 square kilometers in size, and batholiths are larger.
17. Shield volcanoes, such as those in Hawai'i or the Galápagos Islands, are almost
always going to be composed of basalt because
a. basalt is derived from mafic magmas, which usually have very low viscosities.
b. basalt is produced by explosive volcanic eruptions that rain down vast quantities
of ash on the landscape.
c. basalt is the end-product of magma fractionation, which yields a magma very high
in silica.
d. basalt is only found in the ocean basins, and never on continents.
18. Porphyritic textures are created in igneous rocks by
a. slow magma cooling.
b. rapid magma cooling.
c. slow magma cooling followed by rapid magma cooling.
d. rapid magma cooling followed by slow magma cooling.
19. An area of the modern coast of the U.S.A. where plate subduction is currently taking
place is
a. the southern California coast
d. from Cape Cod north to the Gulf of Maine
b. the Oregon-Washington coast
e. the eastern Florida coast
c. the Texas-Louisiana coast
f. from New Jersey to Georgia
20. The San Andreas Fault of California, in plate tectonic terms, is
a. a subduction zone.
b. a spreading center.
c. a transform fault, a lateral (sideways) offset of a spreading ridge.
d. an area where the western part of the state is "falling off" into the Pacific Ocean.
e. none of the above.
Geology 141(A): Fall, 2015
First Hour Examination
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Section II: 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; materials outside
the space allotted will not be read. PLEASE ALSO try to 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; there are 35 points possible for this
entire section.
☛ (And
PLEASE remember as well that, as promised on the syllabus, I WILL deduct a
point each time I see "volcanoe" or "techtonic" in any response!)
21. Please identify three of the nine "big ideas" of Geology, as introduced in the first
lecture, and that must frame any discussion of our understanding of the Earth and
our place in it. (5 points: 2-2-1)
(1)
(2)
(3)
22. Please label each of the four major physical subdivisions of the interior of Planet
Earth on the cross-sectional diagram below. (5 points total)
What major element makes up most of the innermost two units?
23. In plate tectonic theory, the Earth's surface is underlain by relatively rigid plates,
generally 100-km thick, that are collectively called
.
These ride somewhat passively over a deformable, plastic unit 200-400 km thick,
that is referred to as the
. (5 points: 3-2)
23. New crustal material is generally being created at Zones of
and destroyed at Zones of
. (5 points: 3-2)
Geology 141(A): Fall, 2015
First Hour Examination
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24. Please identify three of the independent lines of evidence, other than the apparent fit
of continental margins, that support the combined theories of continental drift and
plate tectonics. Be sure to indicate how each line of evidence supports these
concepts! (10 points: 4-3-3)
(1)
(2)
(3)
Geology 141(A): Fall, 2015
First Hour Examination
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25. The viscosity of a magma is determined by three factors, which are (5 points: 2-2-1)
(1)
(2)
(3)
Section III: Geography. On the maps on the following page (the maps are printed
back-to-back), please locate precisely each of the following localities or features.
FOR SMALL FEATURES OR LOCALITIES, please use a sharp arrow drawn from
your label to the feature, so 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! (10 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:
Minnesota
Austria
Cascade Range
Philippine Islands
Ontario
Andes Mountains
South Carolina
Uganda
Maine
China
Grade on exam: __________________ out of 125 possible*.
* If this is below 90, please see me within the next week !!!
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.
- Consult with your geologist for any eruption that lasts longer than four hours ....
Geology 141(A): Fall, 2015
First Hour Examination
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Geology 141(A): Fall, 2015
First Hour Examination
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