Download Final Exam, Fall, 2015

Geology 141(A)
Fall, 2015
Name
9:00 a.m. in Arey 5
17 December, 2015
GE141(A):
Earth & Environment
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 300
points, or 30% 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 remember that 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. Please come to me to get your exam any
time during JanPlan. ☛ IF AND ONLY IF you will NOT be on campus in
January, please enter your mailing address here, so your exam can be returned to you:
"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
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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Section I: Multiple choice. Please circle the letter of the response that is correct or
that BEST answers the question or completes the statement. PLEASE READ EACH
QUESTION AND RESPONSE OPTION CAREFULLY! I am not trying to trick
you, but missing a key word in a question can result in an error in judgment! There is
only one best answer for each question. Each question is worth 4 points; this
section is therefore worth 200 out of the total of 300 for the exam.
1. New oceanic crust is continually 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.
2. The only mineral group other than the silicates that is of major importance for its
bulk in the crust is the
a. feldspars
c. phosphates
e. sulfates
b. carbonates
d. sulfides
f. oxides and hydroxides
3. 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.
4. 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.
5. While hiking with friends in southern Chile during JanPlan, you encounter an
isolated, snow-capped mountain that shows the profile depicted in the sketch below.
Your friends want to go around it, to get to the lake on the other side for some
swimming. You insist on checking it out because you're pretty certain, based on its
location and form, that the rocks in it will be
a. shales with abundant fossils.
c. basalts with phenocrysts of olivine (peridot)
b. high-silica volcanics.
d. an ancient carbonate reef, including fossils.
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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6. 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.
7. The source of many of the cements that hold sedimentary rocks together is
a. magma from deep within the mantle.
b. chemical weathering of unstable minerals at or near the Earth's surface.
c. cosmic dust from space that trickles down between the grains.
d. micro-organisms living between the grains, that stick to them when they die,
eventually gluing the grains together.
8. Typical cements in sedimentary rocks include all of the following except
a. quartz
b. clays
c. chlorite
d. hematite
e. calcite
9. The factor(s) that have contributed the most to shortening and thickening of the
continental crust is/are
a. deposition of sediments on top of the continents.
b. volcanism that has piled up tens of kilometers of volcanic rock on the continents.
c. folding and reverse faulting, including thrust faults, of pre-existing rock units.
d. weathering of rocks and minerals to create soils that are less dense and thus
thicker than the rocks from which they were derived.
10. Coal, as a sedimentary rock, is derived from the
a. weathering of diamonds and graphite to amorphous (non-crystalline) carbon in
soils.
b. accumulation of vast quantities of organic matter over time, and its gradual
reduction to massive, amorphous carbon.
c. alteration of basalt by hot water, in hydrothermal alteration, a metamorphic
process
d. evaporation of vast quantities of carbon-rich waters in ancient lakes.
11. The two common rock types that are dominated by carbonate minerals are
a. gneiss and granite
c. shale and sandstone
b. limestone and marble
d. slate and schist
12. Limestones are rarely encountered in subduction-zone complexes because
a. subduction zones are usually in cold places like Kamchatka and the Aleutians, and
limestone forms in warm environments.
b. subduction zones create marine trenches, which are so deep that carbonate
sediments settling to the bottom dissolve in the high pressures below 4 km depth.
c. carbonates are forming today, as in the Bahamas and Florida, whereas subduction
zones are all ancient features.
d. subduction-zone complexes form in the ocean, and limestones all form in fresh water
environments.
13. Chesapeake Bay is a very low-energy depositional environment. This means that the
sediments you would expect to be accumulating here would likely become what kind of
sedimentary rock in the long-term geologic future?
a. conglomerate
b. sandstone
c. shale
d. basalt
e. schist
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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14. Felsic magmas typically produce plutonic rocks, rather than volcanic ones, because
a. felsic magmas are formed deep in the mantle, and it's too far to the surface.
b. felsic magmas only form in the crust, not in volcanoes.
c. felsic magmas are much more viscous than mafic magmas.
d. felsic magmas are never associated with tectonic plate margins.
15. The rocks that make up the continental shields (e.g., the Fennoscandian Shield, the
North American Shield, etc.) are predominantly
a. plutonic igneous and metamorphic
c. volcanic
b. sedimentary
d. limestones
16. Island arc systems are created by
a. subduction of continental lithosphere beneath an oceanic lithospheric plate.
b. subduction of oceanic lithosphere beneath an oceanic lithospheric plate.
c. segments of the mid-oceanic rise and ridge system that have grown above the water
level in the ocean.
d. build-up of extensive fringing reefs in tropical environments.
17. A basalt is a volcanic rock typically about 50% SiO2 in composition, and is comprised
principally of high-temperature minerals at the top of Bowen's Reaction Series. You
would thus expect it to be made up of what minerals?
a. quartz, muscovite and biotite
c. olivine, pyroxene, and Ca-plagioclase
b. orthoclase, biotite and hornblende
d. Na-plagioclase, hornblende, and biotite
18. Cosmogenic nuclide dating is useful to determine the ages of
a. organic matter less than 40,000 years old.
b. any igneous or metamorphic rock over 1 million years old.
c. very old rocks of the shields.
d. exposure of rock surfaces to the sky.
19. Radiocarbon dating is useful to determine the ages of
a. organic matter less than 40,000 years old.
b. any igneous or metamorphic rock over 1 million years old.
c. very old rocks of the shields.
d. exposure of rock surfaces to the sky.
20. Potassium-argon (and argon-argon) dating are appropriate to determine the ages of
a. organic matter less than 40,000 years old.
b. any igneous or metamorphic rock over 1 million years old.
c. very small samples of organic matter.
d. exposure of rock surfaces to the sky.
21. In a marine trench off a continental margin , muddy sands are accumulating as rivers
from the on-shore mountains bring millions of tons of sediments down to the sea.
They slide down in great turbidity currents into the murky depths. As subduction
continues, some of them are incorporated into the continental margin, as arkosic
graywackes (graywackes that also meet the criteria for being arkoses). As the pressure
and heat constantly increase, some of these repeatedly metamorphose. Eventually,
however, temperatures become so high that they completely melt. When they then recrystallize, the rock that's most likely going to be the end product will be a(n)
a. obsidian
b. granite
c. quartzite
d. gneiss
e. schist
f. slate
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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22. The following section shows fossils of the bones of an early whale flipper embedded in
sandstones, and fossil trilobites in underlying shales. The dike is 437 million years old.
The eroded lava flow is 42 million years old. How old are the whale bones?
a. you can't say without more information.
b. less than 42 million years.
c. older than 42 million years but younger than 437 million years.
d. older than 437 million years.
23. In reference to this same diagram, how old are the trilobites?
a. you can't say without more information.
b. less than 42 million years.
c. older than 42 million years but younger than 437 million years.
d. older than 437 million years.
24. How would you have determined the age of the lava flow and the dike?
a. radiocarbon dating
b. cosmogenic nuclide dating
b. potassium-argon dating
d. rubidium-strontium dating
25. Maximum chemical weathering, maximum nutrient availability, and therefore
maximum biological activity are to be found where in a soil?
a. in the A horizon
c. in the C horizon
b. in the B horizon
d. in the unweathered parent material
26. Of all the phenomena that have been applied to the prediction of future earthquakes
in seismically active areas, the one that is least reliable (some would say totally
unreliable) is
a. increased levels of radioactivity in well water.
b. a sudden decrease in the numbers of small, background earthquakes.
c. water levels in wells dropping unexpectedly.
d. reports of animals behaving strangely or running away.
e. increases, then decreases, in the electrical resistivity of rocks (i.e., their resistance
to passing electrical current).
f. measured warping of the ground surface in the area, either local rises or drops in
elevation.
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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27. Both diamond and graphite are minerals composed only of the element carbon. The
difference between them must be that
a. diamond is natural while graphite is synthetic.
b. diamond is crystalline while graphite isn't.
c. diamond is found in rocks, but graphite is organic.
d. their crystalline structures are different.
28. Evidence in support of the combined theories of plate tectonics and continental drift
include all of the following EXCEPT
a. apparent "fit" of continental shorelines
b. the fact that the Earth's magnetic field periodically reverses polarity.
c. matching geology (rock types and structures) across areas where it looks like
continents "fit" together.
d. identical ancient fossils on multiple continents, even though modern biotas are
totally different.
29. A metamorphic rock that would be the most likely product of the recrystallization of
an ancient coral reef would be a
a. gneiss
b. schist
c. marble
d. slate
e. phyllite f. quartzite
30. The sand and gravel in stream systems are mostly carried in the
a. dissolved load
c. suspended load
b. bed load
d. competence load
31. The silt and clay in stream systems is mostly carried in the
a. dissolved load
c. suspended load
b. bed load
d. competence load
32. A conglomerate is a sedimentary rock that would most likely reflect sediments
deposited in what kind of setting?
a. a stream channel
c. a sand dune system
e. the deep ocean basin
b. a quiet lake basin
d. a peat bog
33. Karst landscapes are solution-dominated terrains that are almost always underlain by
a. sandstones
c. limestone
e. metamorphic rocks
b. shales
d. granites
f. basalt
34. The dominant (i.e., most important) agent of erosion in deserts, over time, is
a. wind
b. running water
c. chemical weathering
d. mechanical weathering
35. Two metamorphic rocks that are dominated by their primary chemistry, more than
metamorphic grade, are
a. quartzite and marble
c. gneiss and schist
b. slate and schist
d. slate and gneiss
36. The continental crust of Earth has been thickened and shortened by
a. tensional stresses, producing normal faulting.
b. compressive stress, producing reverse faulting and folding.
c. compressive stresses, producing normal faulting.
d. tensional stress, producing reverse faulting and folding.
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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37. The "Basin and Range" geomorphic province of the United States consists of a series of
north-south trending mountains and basins that stretch from the Sierra Nevada in the
west to the Rocky Mountains in the east. This has been created by
a. upwelling of magma from beneath the Yellowstone mantle plume ("hotspot").
b. shallow subduction of the Farallon Plate, which has uplifted the entire region.
c. shearing stresses along the San Andreas transform fault system.
d. unknown processes that geologists still haven't figured out.
e. glaciation in the region, from ice that flowed south out of Canada.
38. The many earthquakes that have plagued the U.S. state of Oklahoma in the past few
years are the result of
a. incipient rifting in this part of North America.
b. upwelling of a mantle plume that has started a new small volcanic province.
c. re-injection of waste water from oil extraction into the deep underground rocks.
d. tectonic stress from the leading edge of the Farallon Plate, which has been subducted
beneath the western margin of North America.
39. When Mt. Pinatubo erupted in the Philippines in 1991, the most damage was done by
a. lava flows that buried the nearby towns and villages.
b. pyroclastic flows and heavy volcanic ash deposition.
c. the earthquakes and lightning that came with the volcanic eruption.
d. local climate change, that resulted in heavy snow in this normally subtropical region.
40. A major earthquake of magnitude 8 represents about how much more ground shaking
and energy release than one of magnitude 2, which is only barely going to be
detectable?
a. about 1,000,000 times as much shaking, and 729,000,000 times the energy.
b. about 1000 times the shaking and 90,000 times the energy.
c. about 10 times the shaking and 300 times the energy
d. about 4 times the shaking and 30 times the energy.
41. The water table in an area is
a. a flat theoretical surface below which all void space may be filled with water.
b. a variable surface, that rises and falls seasonally, below which all void space is filled
with water.
c. the bottom of an aquifer, where the rocks or sediments are totally nonporous or
impermeable.
d. an arbitrary level, set at 100 feet below the ground's surface for legal reasons.
42. An example of a geologic substrate that would make an excellent potential aquifer
would be
a. a granite
b. sand and gravel
c. shale
d. gneiss
43. An aquifer is
a. any subsurface rock or sediment unit that contains water.
b. a subsurface rock or sediment with high porosity, high permeability, and drinkable
(potable) water.
c. a canal, which carries surface water from a river or reservoir to where it is needed.
d. a mineral that contains water in its crystal structure – e.g., gypsum (CaSO4·2H2O)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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44. The groundwater in an aquifer is water that has come from
a. original water in the sediments as they were deposited.
b. water that's been underground since the Earth came into existence.
c. rain and melting snow and ice that constantly seep into the ground surface.
d. water from lakes and rivers that flows back into sediments under the land.
e. water from an ancient prehistoric flood that soaked into the Earth.
45. Groundwater contamination can come from
a. agricultural and industrial chemicals, whether applied or spilled accidentally.
b. overloaded or improperly designed septic systems.
c. road salts.
d. leaking underground oil pipelines.
e. all of the above.
f. none of the above.
46. What percentage of your class relies on groundwater (either from wells or natural
springs) for at least part of their water supply at home?
a. about 10%
c. about 50%
e. about 90%
b. about 25%
d. about 67%
47. The mixed jumble of materials deposited directly by glaciers on a landscape is called
a. till
b. outwash
c. karst
d. debris
e. soil
48. The process by which sediments such as sands are moved along a coast, by currents
and waves that strike the coast consistently at an angle, is called
a. tidal bore
b. longshore drift
c. erosion
d. upwelling
49. Coral atolls, such as those of the Tuamotu Archipelago, are formed by
a. explosive volcanic activity that creates a ring of debris around an ancient volcano.
b. upward growth of corals in tropical waters after a volcanic island becomes dormant
and erodes, while it slowly sinks beneath the sea surface.
c. deposition of corals and other marine organisms by ocean currents that bring them
from distant sources to be deposited on the beaches around an island.
d. uplift of deep parts of the sea floor by mantle plumes, that push the oceanic crust
upwards until it breaks through the sea surface in a ringlike structure.
50. You are visiting friends in Oregon for the summer, and visit a local beach. There, you
observe that most of the beach consists of cobbles and boulders that are at least 4
inches (10 cm) in diameter. Your friends insist that the conditions are always like they
are this day – small waves, perhaps 2 feet high, splashing weakly on the shore.
However, you know that
a. this is an environment that is usually even less energetic, since there are no clays,
silts or sands that have been washed in to fill the gaps between the rocks.
b. this is a coast that used to be on a river.
c. this coast often has much higher energy levels and big waves, since everything finer
than these large rocks has been eroded and removed.
d. this coast must have been glaciated, since that's the only way Nature can move rocks
this large.
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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Section II: Short answers, fill-ins, etc. Please respond to each question in the most appropriate
fashion; make your responses concise and to the point, but thorough. There should be ample
space provided for an adequate response. PLEASE WRITE LEGIBLY; I can't give credit
for responses I can't read! Please make all verbal responses in complete sentences and proper
English and avoid using cryptic abbreviations or shorthand notation such as b/c, w/, etc. The
number of points for each question is indicated in parentheses after the question; there are 80
points possible for the entire section. (And PLEASE remember that, as promised on the syllabus,
I will deduct a point each time I see "volcanoe" or "techtonic!" )
IMPORTANT! Please feel free to utilize sketches or diagrams in any place where you feel they
can help to convey the essence of your response.
51. The transferric elements are those that are found above iron on the Periodic Table of
the Elements (below). Please explain the significance of these trans-ferric elements, as
they relate to Earth's history. (5 points)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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52. Please identify three of the nine "big ideas" of Geology, as introduced in the first
lecture, and that must help to frame any discussion of our understanding of the Earth
and our place in it. (5 points: 2-2-1)
(1)
(2)
(3)
53. What is the carbonate compensation depth in the world's oceans, and what is its
significance? (5 points: 3-2)
54. The diagram below shows a major tectonic zone in the world, in a diagram type that
I've used multiple times this semester in class. What is going on here, in plate
tectonic terms? How can you tell? (10 points: 3-7)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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55. The aerial photo below shows the Oso, Washington, landslide that killed some 43
people on March 22, 2014 – the deadliest landslide in United States History. The
slide occurred after some 40 days of continuous rain. Though I used this example in
class, you should be able to answer all the questions based on your basic knowledge
of mass movements, even if you had never seen this particular landslide before.
(a) What is the complete, formal name [2 words] of the initial failure type? (2 points)
(b) What did this failure become, as it engulfed 49 homes and dammed the river? (2 pts.)
(c) What are three specific ways in which all the water from that rain contributed to
this failure? (6 points: 2-2-2)
(a)
(b)
(c1)
(c2)
(c3)
56. What is the significance of chemical weathering to plants? (5 points)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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57. What is aquifer drawdown, and how does it occur? (5 points: 3-2)
58. The diagram below shows a sketch map of a section of the Whatsatooya River of
central Arkansas. Write a big A at any site where erosion is going to be the dominant
process, a big B where deposition will be the dominant process along the channel,
and a big C where a new oxbow may be created in the relatively near future.
(5 points: 2-2-1)
59. Sketch an appropriate diagram and use it to explain how orographic (“rainshadow”) deserts are created, such as those of the western U.S.A. (10 points)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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60. The two mechanisms by which glaciers flow downhill are (5 points: 3-2)
and
61. Identify two ways that glaciers directly modify the landscape. (5 points: 3-2)
(a)
(b)
62. Identify two ways that glaciation indirectly affects the Earth's landscapes.
(5 points: 3-2)
(a)
(b)
63. Why are tropical coasts often dominated by carbonate sediments, much more so than
those at higher latitudes (i.e., in colder climates)? (5 points)
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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Section III: Geography. On the maps on the following page (the maps are printed back-toback), 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! (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:
Alberta (AB)
Prince Edward Island (PE)
Bay of Fundy
Virginia (VA)
Georgia (GA)
Louisiana (LA)
Colorado (CO)
Oregon (OR)
Nebraska (NE)
San Francisco Bay
❄
❄
On the map of the world:
Ural Mountains
Greenland
Bahamas
Maldive Islands
Puerto Rico (PR)
Yucatán Peninsula
Red Sea
Kuril Islands
Persian Gulf
Cuba
❄
❄
❄
Grade on exam:
out of 300 possible.
Total for Course:
out of 1000 possible.
Course Grade:
Geography, shmeography ....... check out the map that was actually broadcast by MSNBC on August
14, 2013 – moving major Northeast cities around by hundreds of miles! The map on the right shows
the actual locations of these cities. And you thought I was just kidding this semester ..........
Have a great holiday break!
Geology 141(A): Fall, 2015
Lecture Final Exam ination
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Geology 141(A): Fall, 2015
Lecture Final Exam ination
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