Name
Geology 141
Spring, 2001
5 March, 2001
Ge141: Physical Geology
First Hour Examination
INSTRUCTIONS: Please read all 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 100 points, or
10% 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.
"The moment one gives close attention to anything, even a
blade of grass, it becomes a mysterious, awesome,
indescribably magnificent world in itself."
- Henry Miller
...
Geology 141: Spring, 2001
First Hour Exam
... Page 2 ...
Section I: Multiple choice. Please circle the letter of the response that is
correct or that BEST answers the question or completes the statement. There
is ONLY ONE BEST ANSWER for each question. Each question is worth 3
points; this section is worth 60 out of the total of 100 for the exam.
PLEASE READ EACH QUESTION AND RESPONSE CAREFULLY !
1. The most abundant element in the Earth's crust, by weight as well as volume, is
a. silicon
c. iron
e. aluminum
b. nickel
d. oxygen
f. carbon
2. Evidence that the Earth and our solar system are a second-generation star system comes
from the fact that
a. iron is the main element in the core.
b. the Earth's atmosphere is mostly oxygen and nitrogen, not hydrogen.
c. the main rock type in the oceanic crust is basalt.
d. elements above iron on the period table are common on Earth.
e. a major meteorite impact in the Yucatan Peninsula killed off the dinosaurs.
3. New sea floor (and therefore new oceanic lithospheric plates) is created
a. at subduction zones
b. by burial of thick sediment deposits eroded off the land.
c. by accumulation of organic sediments at the bottom of the ocean basins.
d. by melting of crust in continent-continent collisions.
e. by magma upwelling at the mid-oceanic rise and ridge system
4. Major zones of lithospheric plate subduction are located at all of the following except
a. along the east coast of the United States
b. the west coast of South America
c. the eastern margin of the Caribbean Sea
d. along the coast of Japan
e. along the Aleutian Islands
5. The dominant mineral group on Earth, making up some 95% of the crustal rocks, is
a. the oxides and hydroxides
d. the silicates
b. the carbonates
e. the sulfates and sulfides
c. the native elements
6. All minerals must meet all the following criteria except
a. they are all naturally occurring
b. they are all inorganic solids
c. they all have an ordered (crystalline) internal structure
d. they all have a constant chemical composition, or one that varies within
set limits.
e. they all contain either silicon or oxygen
7. The basic building block of all silicate minerals is the
a. silica tetrahedron
b. quartz crystal
c. Bowen's Reaction Series
d. water molecule
e. aesthenosphere
Geology 141: Spring, 2001
First Hour Exam
... Page 3 ...
8. The source for all magmas is
a. the impact of meteorites on the Earth's surface.
b. vast pools of molten material in the Earth's core.
c. large pools of molten material in the aesthenosphere, left over from Earth's
formation.
d. melting or partial melting of pre-existing rocks.
9. While visiting friends in Arizona last summer, you found yourself in an area where
almost all of the rocks on the sides of a volcano you climbed had a texture that looked
pretty much like the cartoon below.
This particular rock texture is called
a. porphyritic
c. pyroclastic
b. vesicular
d. aphanitic
10. This kind of texture in igneous rocks is created by
a. two-stage cooling of any magma
b. rapid cooling of very high-silica magma
c. slow cooling of low-silica magma
d. explosive eruptions of large fragments of solid materials.
11. Felsic magmas are most likely to crystallize underground because
a. they are low in silica and very high temperature, making them very fluid.
b. they are high in silica and relatively cool, making them extremely viscous.
c. they originate deep in the mantle beneath the mid-oceanic rise and ridge
system.
d. they originate down in the outer core, where everything is molten.
12. The only non-silicate mineral group that is more important for its volume in the crust
than for its economic value is the
a. the oxides and hydroxides
d. the feldspars
b. the carbonates
e. the sulfates and sulfides
c. the native elements
13. Of all the volcanoes listed below, the only one that is not a stratovolcano is
a. Mauna Loa, Hawai'i
d. Mt. Hood, Oregon
b. Mt. Fuji, Japan
e. Mt. St. Helens, Washington
c. Mt. Shasta, California
f. Popocatepetl ("El Popo"), Mexico
14. The Columbia Flood Basalts, Deccan Traps of India and Siberian traps all owe their
origins to
a. eruptions of highly fluid magmas from mantle plumes that were
overridden by migrating continental plates.
b. explosive eruptions of highly viscous magma, that blanketed the landscape
with a thick layer of volcanic ash.
c. deep weathering of old granitic rocks to allow wind and water to erode
caves in the rock faces.
d. deposition of thick layers of windblown sand and silt.
Geology 141: Spring, 2001
First Hour Exam
... Page 4 ...
15. A batholith (e.g., the Katahdin Batholith in Maine) is, by definition,
a. the core of an eroded ancient volcano.
b. any high mountain region underlain by resistant igneous rocks.
c. any area of igneous rock exposed over an area of > 100 km2.
d. an area of plutonic igneous rock exposed over an area of > 100 km2.
16. The heat source that produces most magmas is
a. leftover heat from the formation of the Earth.
b. solar energy being concentrated by quartz crystals in rocks.
c. unknown processes acting within the Earth's core.
d. radioactive decay or friction deep within the Earth.
17. Intermediate magmas are formed most commonly by
a. melting of rocks of the upper mantle.
b. mixing of magmas from the mantle and core.
c. melting of continental rocks.
d. mixing of mantle or oceanic crust magmas with those from continents.
18. The dominant agent of destruction in the 1995-98 eruption of the Soufriere Hills
Volcano on the island of Montserrat was the
a. thick, black basaltic lava flows that buried the entire island.
b. earthquakes that opened vast crevasses in the land.
c. raging forest fires set off by the eruption, which burned everything on the
island.
d. pyroclastic flows that blasted down the mountainside.
19. The difference between chemical and mechanical weathering is that
a. chemical weathering involves changes in the actual minerals present,
whereas mechanical weathering reduces rocks and minerals into smaller
pieces of the same composition.
b. chemical weathering occurs by chemicals interacting with minerals, while
mechanical weathering is the wearing away of minerals by things rubbing
against them.
c. chemical weathering occurs in place, mechanical weathering involved
movement of materials away from the site.
d. mechanical weathering only affects silicates; chemical weathering attacks
all other minerals.
20. Which of the following is NOT part of what defines a soil?
a. soils are naturally formed bodies of unconsolidated materials.
b. soils form in place by natural processes, and cannot be deposited.
c. soils must always contain some organic matter.
d. soils form by weathering of rocks or sediments.
Geology 141: Spring, 2001
First Hour Exam
... Page 5 ...
Section II: Short answers, fill-ins, etc. Please respond to each question in the
most appropriate fashion. Please make your responses concise and to the
point, but thorough. There should be ample space provided for an adequate
response; 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; there are 40 points possible for this entire section.
21. Cite two lines of direct evidence, other than the apparent fit of continental margins, that
directly support the combined theories of continental drift and plate tectonics. Explain
how each line of evidence supports these concepts. (10 points: 3-2-3-2)
1.
2.
Geology 141: Spring, 2001
First Hour Exam
... Page 6 ...
22. In the chart below, the silica contents of the three principal magma classifications are
indicated. Please enter the names for each of these three major magma categories, as
well as the common volcanic and plutonic rock types that result from the crystallization
of each magma type (10 points; 1 point for each answer plus 1 bonus point for the first
correct answer).
Magma type
Silica Content
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45-55%
55-65%
Volcanic Rock
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>65% |
Plutonic Rock
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23. Draw in and label clear examples of a dike and a sill in the following cartoon
that shows the geological stratigraphy in southwestern Utah. (5 points: 3-2)
24. The five basic factors that influence the development of a soil are:
(5 points, 1 point each)
Geology 141: Spring, 2001
First Hour Exam
... Page 7 ...
25. 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 there can be no doubt about
what you are labeling. (10 points, 1 point each)
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:
Montana
Andes Mountains
Lake Erie
Montserrat
Sierra Nevada
Kamchatka
Vermont
Sumatra
Mississippi
Hawai'i
Grade on exam: __________________ out of 100 possible*.
* If this is below 70, please see me within the next week !!!
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.