Download Final Examination Key

GLY 2010 - Section 51060
August 6, 2012
105 points
35 students took exam
Name
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Evolution of the Earth -- Final Examination Key
THIS IS A CLOSED BOOK, CLOSED NOTE EXAMINATION. ANY USE OF BOOKS,
NOTES, ETC. IS CHEATING. ALL ELECTRONIC DEVICES (CELL PHONES, COMPUTERS,
ETC.) MUST BE TURNED OFF AND OUT OF SIGHT. USE OF ELECTRONIC DEVICES IS
CHEATING. ANY FORM OF CHEATING WILL RESULT IN AN F IN THE COURSE AND
REFERRAL TO THE STUDENT CONDUCT COMMITTEE FOR FURTHER DISCIPLINARY
ACTION.
You have until 12:55 p.m. for this examination. If you finish early, check your exam. Be
sure you answered all questions.
Numbers in red to the left of the question number are the number of incorrect responses.
Blue text is instructor comments, not on the original test.
True-False -Print the letter T or F in the blank to indicate if each of the following statements is true
or false. Illegible answers are wrong. (1 point each)
1. Deep focus earthquakes are associated only with convergent plate margins.
15
T
4
T
2. The widest continental shelves are associated with passive plate margins. The east coast
of Florida is an example.
4
F
3. The initial rupture point of an earthquake, where strain energy is first converted to elastic
wave energy, is known as the epicenter.
10
T
4. A mid-ocean ridge is more apt to have a rift valley if it spreads slowly, rather than
rapidly.
10
T
5. Lithospheric plates are thinnest in the oceans.
2
F
6. An instrument that detects, magnifies, and records vibrations is a hydrograph.
6
F
7. Hydrothermal vents known as black smokers emit clouds of sulfide minerals and are
colder than white smokers, which emit no sulfides.
9
T
8. The great basalt plateaus of the continents (Columbian, Deccan) mark current or ancient
rift zones
6
T
9. Low frequency sound waves used in seismic profiling can cause problems for forms of
marine life, such as dolphins, that use sound waves for echolocation.
1
21
F
10. Continental shelf materials are mostly of marine origin. As discussed in class, the
shelves are extensions of the continents, and will be uncovered during glacial periods. They
are composed mostly of detritus off the continents.
12
T
11. The deep ocean basins cover about 30% of the earth’s surface, similar to that covered by
land.
26
F
12. The mid-ocean ridges are mountains found on the floor of the Pacific, Indian, and
Atlantic Oceans.
4
F
13, In the entire four billion year history of the earth, there has only been one
supercontinent, known as Pangaea.
6
T
14. Wildfires increase the possibility of mass movements, especially the very destructive
debris flows.
6
T
15. A blast of air, approaching hurricane force, may precede the front of a large mass
movement
17
F
16. The collective name for all stream deposited sediment is colluvium. Alluvium, not
colluvium.
6
T
17. Lahars are a special type of mudflow produced on the slopes of a volcano. Volcanic ash
and hot gases melt accumulated snow and glacial ice, producing large quantities of mud.
7
F
18. The velocity of a stream is nearly constant across the entire width of the stream, so
measuring stream velocity at one point is sufficient to insure good quality data.
1
T
19. Construction of a dam across a river temporarily establishes a new base level for the
river, until the dam is removed or collapses. This may slow the river velocity above the
dam, causing sediment to be deposited.
3
T
20. The largest size particle diameter a stream can carry is proportionate to the square of the
streams velocity, which is why floods sometimes move huge boulders.
11
F
21. When the river gradient is steep, the cross-sectional profile of a river cut stream channel
will be U-shaped.
20
F
22. The ability of a rock or sediment to allow a fluid (water) to flow through it is known as
the porosity.
0
T
23. Unconfined aquifers, such as the Biscayne Aquifer in South Florida, are subject to rapid
recharge from above, but may also be easily contaminated by spills, especially if they are
shallow.
2
0
T
24. Artificial clay layers are used to line landfills, so that water from the landfill won’t
leach into the aquifer, because the clay layer acts as an aquiclude.
17
F
25. In order to get water from an artesian well, it is necessary to pump the water to the
surface. By definition, artesian wells are self-pressurized.
9
F
26. The use of geothermal fluids to generate power is pollution-free, since the fluids are
extremely pure fresh water.
0
T
27. In improperly constructed drinking water wells, sewage effluent from septic tanks can
infiltrate the drinking water supply.
5
T
28. Worldwide, more than 85% of glaciers are retreating.
10
T
29. Valley glaciers are confined by surrounding bedrock highlands, and generally move
down steep to very steep surfaces.
17
F
30. Glaciers can form on land or in the ocean.
6
T
31. Loess, derived from Pleistocene glaciers, is found as far south as Louisiana and
Mississippi.
19
F
32. Periodic variations of the earth’s orbit and axial rotation can explain all of the
observed changes in global climate within the time frame these changes have been
observed, from the beginnings of the industrial revolution to the present. Orbital
variations have periods from tens to 100's of thousands of years, and have very little
effect over a less than 200 year period.
9
T
33. Milder winters in high latitudes lead to climate warming, and greater snowfall. Cooler
summers would reduce snowmelt. Combined, this might trigger ice formation, and lead
to an ice age.
2
T
34. Certain gases, known as greenhouse gases, absorb infrared radiation, and prevent it
from escaping from earth. This raises the average global temperature.
9
T
35. After a rapid increase in sea-level from 16,0000 to 8,000 years before present, sealevel has been nearly constant for 8000 years. Since 1900, it has risen about 20
centimeters, and the rate of rise is accelerating.
13
F
36. A desert is a hot, arid region.
4
T
37. In hyper-arid regions, such as the Sahara and Atacama deserts, the potential annual
evaporation divided by recorded average annual precipitation may exceed 100.
3
5
F
38. “Desert pavement” refers to a surface coating sprayed by humans on the surface of arid
regions to prevent aeolian erosion.
28
F
39. In the dust bowl movie shown in class, and the picture of the storm approaching a
village in Senegal, the material in the air was composed mainly of sand, accounting for the
name “sandstorm”. This is dust, not sand, which is too heavy to rise high.
11
F
40. Alluvial fans and sand dune deposits both obey the Law of Original Horizontality.
10
T
41. After glaciers melt, the land under them rises. This is still occurring in the area north of
Lake Superior.
24
F
42. On both the east and west coasts of the United States, longshore currents carry sand
from south to north. North to south
7
T
43. Erosion of a headland can create a sea-arch, which can be further eroded to form a sea
stack.
6
T
43. Hooks, such as the northern tip of Cape Cod, caused be refraction of waves around the
spit.
16
T
44. Waves and ocean currents transport energy, whose source is either solar radiation or
gravitation interaction.
15
F
45. Competence is the maximum load a stream can carry, which is directly related to the
discharge of a stream.
3
F
46. Human teeth are composed of calcium phosphate, and have a structure like the mineral
apatite. Teeth are therefore examples of minerals. Midterm repeat
15
F
47. In the rock cycle, sedimentary rocks may be converted to metamorphic rocks, but it is
not possible to convert metamorphic rocks to igneous rocks. Midterm repeat
5
T
48. Large volcanic eruptions, like Mount Pinatubo in 1991, can cool the earth’s climate for
one to several years. Midterm repeat
8
T
49. Graded-beds are formed when heavy or large particles sink from a turbidity current first,
followed by medium, then small, particles. Midterm repeat
9
F
50. The top of Mt. Everest is composed of marine limestone, indicating that the earth was
flooded to a depth at least 30,000 feet higher than today’s sea-level. Midterm repeat
4
T
51. Metamorphic fluids often produce ion exchange, which can partially or totally reset
radiometric clocks. Midterm repeat
4
Multiple-Choice - Choose the best response to each statement or question. Print the letter
corresponding to your choice in the blank. (1 point each)
1
A
1. What are the most intense energy release per unit time of any natural event, except
for meteorite impacts?
A. Earthquake
B. Hurricane
C. Tornado
D. Tsunami
24
C
2. The East African rift zone is an example of what type of plate boundary?
A. Convergent ocean-ocean
B. Divergent ocean-ocean
C. Divergent continent-continent
D. Transform ocean-continent
10
C
3. The San Andreas fault in California has which of the following features associated
with it?
A. Alkaline volcanism
B. Fissure type volcanic eruptions
C. Shallow focus earthquakes
D. None of the above
13
C
4. L. Wilson Morley and, nine months later, Frederick Vine and Drummond H.
Matthews proposed an explanation of magnetic stripes. What idea, not widely accepted in
1963, did their explanations depend on?
A. Sea-floor spreading, as proposed by Harry Hess and Robert Dietz
B. Polarity reversals of the earth’s magnetic poles
C. Both of the above
D. None of the above
14
D
5. Shallow, intermediate, and deep focus earthquakes are associated with which type of
plate boundary?
A. Convergent ocean-continent
B. Convergent ocean-ocean
C. Divergent ocean-continent
D. Both A and B
5
6
C
6. Who first proposed a scientifically correct explanation of magnetic stripes, although
his paper was initially rejected and he often does not get credit for his idea?
A. H. Bretz
B. D. Mathews
C. L. Morley
D. F. Vine
8
D
7. Most active continental margins are found where?
A. In the Atlantic ocean
B. In the Arctic ocean
C. In the Indian ocean
D. In the Pacific ocean
11
C
8. These features makes up only 7.5% of the ocean surface, yet contains much of the
wealth of the ocean, including petroleum, natural gas, mineral resources, and huge sand
and gravel deposits.
A. Abyssal plains
B. Continental rises
C. Continental shelves
D. Oceanic plateaus
1
C
9. Oceans cover about what percentage of the earth’s total surface?
A. 40
B. 55
C. 70
D. 85
20
D
10. On which of the following regions of the ocean floor is the slope angle the highest?
A. Abyssal plain
B. Continental rise
C. Continental shelf
D. Continental slope
22
C
11. These features are created by mantle plume volcanism producing copious lavas which
cover and smooth large areas of the ocean floor. The rock consists primarily of pillow
lava, which may reach or exceed 30 kilometers in thickness. They resemble the flood
basalt provinces found on the continents. Which feature is this?
A. Abyssal plain
B. Deep sea fan
C. Ocean plateau
D. Seamount
6
6
D
12. Which of the following descriptions fits that of the mid-ocean ridges?
A. They exceed 70,000 kilometers in length
B. They range from 1000 to 4000 kilometers in width
C. They cover 20% of the earth’s surface
D. All of the above
3
D
13. Mass movement is influenced by which of the following factors?
A. Slope Steepness
B. Vegetation
C. Water
D. All of the above
17
D
14. Which of the following is an example of slow mass movement?
A. Debris avalanche
B. Earthflow
C. Slump
D. Solifluction
4
B
15. The smallest division of a drainage network is called a:
A. Primary
B. Rill
C. Secondary
D. Trunk
1
D
16. Streams may:
A. Erode their stream beds, making the stream channel deeper
B. Flow over the stream bed with little deposition or erosion
C. Actively deposit sediment on the stream bed, building it up
D. Either A, B, or C, depending on the conditions at a particular time
8
A
17. The most common type of river drainage pattern is:
A. Dendritic
B. Radial
C. Straight
D. Trellis
11
C
18. Approximately two-thirds of the groundwater use in the United States is for:
A. Aquaculture
B. Drinking water
C. Irrigation
D. Livestock
7
6
A
19. Deep inside a glacial crevasse, or inside an ice tunnel under a glacier, what color light
will be seen?
A. Blue
B. Green
C. Red
D. White
24
C
20. Which of the following features is not due to glacial erosion?
A. Arte
B. Cirque
C. Lateral moraine are depositional
D. Roche moutonnée
27
C
21. Which of the following can create a dam, similar to an earth-fill dam created by a
human engineer?
A. Lateral moraine
B. Medial moraine
C. Terminal moraine
D. All of the above
18
B
22. When two or more valley glaciers merge, what type of moraine will form as the result
of the merger?
A. Lateral moraine
B. Medial moraine
C. Terminal moraine
D. All of the above
21
A
23. Who first proposed, in 1837, that earth had experienced an ice age?
A. Louis Agassiz
B. J. Harlan Bretz
C. Charles Darwin
D. Milutin Milankovitch
19
A
24. During the Pleistocene epoch of the Cenozoic era, how many times did ice move
south out of Canada into the United States?
A. At least four
B. Three
C. Two
D. One
8
9
D
25. Who first formulated an idea that explained the cause of the Pleistocene glacialinterglacial oscillation by a series of periodic variations of the earth’s orbit and axial
rotation?
A. Louis Agassiz
B. J. Harlan Bretz
C. Charles Darwin
D. Milutin Milankovitch
4
D
26. Deserts may result from:
A. Air-circulation patterns, such as the downdraft regions of Hadley cells
B. Rain shadow effects, where air passing over mountain ranges loses moisture before
descending as a dry air mass
C. Proximity to a region of cold ocean water, where little evaporation occurs
D. Any of the above
30
B
27. Which of the following is NOT an erosional landform found in arid regions?
A. Alluvial fan
B. Barchan dune are depositional
C. Inselberg
D. Mesa
18
D
28. Which of the following dune types are found along A1A and other coastal regions in
Florida where the predominant winds are on or off-shore?
A. Barchan
B. Seif
C. Star
D. Transverse
14
A
29. In some parts of Florida, the coast is lined by mangroves. This is an example of what
type of coast?
A. Organic
B. Primary
C. Secondary
D. Could be any of the above
28
B
30. The presence of a wave-cut bench breaks the force of the waves, and may result in the
formation of what?
A. Cove
B. Headland
C. Sea-arch
D. Sea-stack
9
11
B
31. Which era is known as the age or reptiles, including dinosaurs? Midterm repeat
A. Cenozoic
B. Mesozoic
C. Paleozoic
D. None of the above
10
A
32. Which part of the earth, because if is warm and under pressure, behaves as a plastic,
capable of slow deformation? This part is important because it allows the earth’s plates to
move without severe deformation. Midterm repeat
A. Asthenosphere
B. Core
C. Lithosphere
D. Mesosphere
11
C
33. Which type of chemical bonding has allowed salts to be transferred from the lands
surface to the ocean, by ths process of dissolution? Midterm repeat
A. Covalent
B. Hydrogen
C. Ionic
D. Metallic
7
D
34. Rocks are: Midterm repeat
A. An aggregate of one or more minerals
B. A body of undifferentiated mineral or glassy matter
C. Bodies of solid organic matter
D. Any of the above
12
C
35. Which of the following layers of the earth is a liquid? Midterm repeat
A. Crust
B. Mantle
C. Outer core
D. Inner core
12
C
36. Which chemical weathering process is responsible for the conversion of feldspars,
the most common minerals in the earth’s crust, to clay, an important part of soil?
Midterm repeat
A. Dissolution
B. Hydration
C. Hydrolysis
D. Oxidation
10
15
A
37. Which soil horizon is a mixture of inorganic mineral matter and humus, dark colored
decomposed organic matter? Midterm repeat
A. A-horizon
B. B-horizon
C. C-horizon
D. O-horizon
16
B
38. Most sedimentary rocks originate from which source? Midterm repeat
A. From chemical precipitation of solids from aqueous solutions
B. From fragments of preexisting rocks
C. From precipitates created by living organisms, such as shells
D. All are about the same
13
A
39. Geologists know that a fault is younger than the beds it offsets because of which of
the following laws or principles? Midterm repeat
A. Principle of Cross-cutting Relation-ships
B. Principle of Inclusions
C. Law of Original Horizontality
D. Law of Superposition
Fill-Ins - Write or print in the word or words which best completes each statement or answers
each question. When the statement says “name and describe”, names without descriptions will
receive no credit. Diagrams may be used to supplement answers, where useful. Illegible
answers are WRONG. (1 point per blank)
6
1. The MERCALLI scale of earthquake intensity ranges from I to XII, and is based on
human perception of the earthquake, and damage observed after the earthquake is over.
22
2. A
WATERSHED
(drainage basin) is the total area from which water reaches a stream
25
3. The WATER TABLE
26
4. The ratio of isotopic abundance among isotopes of which element are used as a
separates the vadose zone from the phreatic zone.
geothermometer, allowing us to closely estimate the temperature at various times in the earth’s
past?
33
OXYGEN
5. The movement of sand grains up a dune face by bouncing along the surface is known as
SALTATION
17
.
6. DESERTIFICATION
means degradation of land and vegetation, soil erosion and
the loss of top soil and fertile land in arid, semi-arid, and dry sub-humid areas, caused primarily
by human activities and climate variation
11
6
7. How can a swimmer escape from a rip current?
PERSONS CAUGHT IN A RIP CURRENT SHOULD SWIM SIDEWAYS TO GET OUT OF
THE NARROW FLOW, THEN TURN AND SWIM BACK TO SHORE.
22
8. Viscosity increases as the silica content of magma increases. Why?
AS SILICATE CONTENT INCREASES, MORE CHAINS OF SILICATE TETRAHEDRON
FORM. THESE CHAINS WRAP AROUND EACH OTHER, INCREASING THE INTERNAL
RESISTANCE TO FLOW, WHICH IS THE DEFINITION OF VISCOSITY.
20.5
9. What is the definition of mass movement?
MASS MOVEMENT INVOLVES THE TRANSPORTING OF EARTH MATERIALS
DOWNSLOPE, DUE TO GRAVITY, WITHOUT THE AID OF A TRANSPORTING
MEDIUM, SUCH AS WATER OR ICE
.
10-12. For a divergent ocean-ocean plate boundary, indicate the depth(s) of the associated
earthquake foci, the type of volcanism (if any), and give a real example of this type of plate
boundary
25
10. Earthquake depth?
SHALLOW FOCUS
25
11. Type of volcanism? FISSURE ERUPTION
19
12. Real example? ANY MID-OCEAN RIDGE
13-14 Describe two unique physical features of earth, not known to exist on any other planet in
our solar system. Be specific. Midterm repeat
14.5
13. LIQUID WATER ON THE SURFACE - SOME OTHER PLANETS HAVE
WATER, BUT IT IS EITHER PRESENT AS VAPOR, OR WATER ICE.
11
14. FREE OXYGEN IN THE ATMOSPHERE - FREE OXYGEN MEANS THE
OXYGEN IS NOT COMBINED WITH ANY OTHER ELEMENT. IT IS THE
PRODUCT OF PHOTOSYNTHESIS. OTHER PLANETS HAVE OXYGEN, BUT
ALWAYS COMBINED WITH OTHER ELEMENTS.
12
Matching - Match the description or answer the question in column one with the term associated
with it from column two by printing the correct letter in each blank. Answers may be used once,
more than one, or not at all (One point each)
Column 2
Column 1
4
5
8
C 1. An imperceptibly slow down-slope
movement of soil and near-surface rock
materials, best discerned through the
movement or response of objects affected by
the process.
A. Arte
E 2. The vertical drop in elevation over a
given horizontal distance, which may be
expressed in units like meters/kilometer,
feet/mile, or as a percentage, is known as
what?
D. Flow
G 3. This process is a physical process
that takes place during some earthquakes
that may lead to ground failure; as a
consequence, soft, young, water-saturated,
well sorted, fine grain sands and silts behave
as viscous fluids rather than solids
G. Liquefaction
B. Cone of depression
C. Creep
E. Gradient
F. Horn
H. Ophiolite
I. Phreatic
J. Playa
21
I 4. In the zone of saturation, all available
pore spaces are filled with water. What is
wanother term for this zone?
K. Slide
L. Solifluction
6
6
26
H 5. This type of rocks comprise the
oceanic crust. They are mafic, but often
include serpentinite, formed by
metasomatitism of the mafic rock
M. Tarn
N. Tephra
O. Vadose
K 6. A form of mass movement in which
a single intact mass (rock, soil, or
unconsolidated material) moves downslope
along a slip plane.
P. Well drawdown
B 7. Rapid withdrawal of fluid from a well
causes a localized lowering of the water
table around the well Key word is localized,
which precludes “P”
13
19
A. Arte
M 8. This type of lake forms in a cirque
created by glacial erosion.
B. Cone of depression
10
13
4
A 9. Knife-edged ridge of land, formed by
parallel erosion of two alpine glaciers
C. Creep
F 10. A three or four-sided mountain, cut
by glaciers flowing off an isolated mountain
in several directions
D. Flow
N 11. A general term for fragments of
volcanic rock and lava that, regardless of
size, are blasted into the air by explosions or
carried upward by hot gases in eruption
columns or lava fountains
F. Horn
E. Gradient
G. Liquefaction
H. Ophiolite
I. Phreatic
J. Playa
K. Slide
L. Solifluction
M. Tarn
N. Tephra
O. Vadose
P. Well drawdown
HAVE A GREAT SUMMER!
14
Final Examination Grades (105 possible)
99.5
97.0
91.0
88.5
87.0
85.0 - 2
83.5
83.0 - 2
81.0
80.5 - 2
80.0
78.5
78.0
77.0
75.5
75.0
73.5
73.0
72.5 - 2
71.5
70.5
70.0
69.0 - 2
67.0 - 2
65.0
62.0
60.5
52.5
47.5
A
AB
B-
C+
C
MEAN = 75.8 (72.1%) MEDIAN = 75.5
C-
D+
D
D-
F
In 2011, the mean was 75.6, and the median was 74.5
Comment: There were 18 “Midterm repeat” questions, and the scores on many were not
good. Missing a question once is understandable, but missing it twice shows a definite lack of
preparation.
15