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Geology 101
Sample final exam
Open textbook, notes, labs and handouts, no other textbooks or collaboration.
You have 120 minutes to complete the 100-point exam.
Short answer (answer all questions)
1. Fill in the blanks with either “lithosphere” or “crust”: Tectonic plates are bits of
_________________, which includes the upper mantle and the
_________________.
2. Fill in the blanks with “a rock”, “a mineral” or “both”:
Talc is _________________ ; talc schist is __________________ .
3. a. What sort of luster does mineral Z have?
b. The surfaces you see on mineral Z are due to its cleavage. How many cleavages
does it have?
(extra credit – 2 points) Identify mineral Z.
4. (3 points) A volcano whose magma composition is intermediate will be made
of the rock ________________________ , but if that same magma freezes
in the
magma chamber, that rock will be called _________________________ .
Further, if that volcano erupts the same lava but a lot of gas bubbles get trapped
in the rock,
that rock will be called ______________________ . To help you out, the
words to go in the blanks are “diorite”, “pumice” and “andesite” (not necessarily
in that order).
5. You take a GPS reading and get 47° 32’ 8” N, 122° 2’ 36” W. A little while later,
you are at 47° 31’ 34” N, 122° 3’ 4” W. In what compass direction did you move?
6. A sedimentary rock you are testing does not fizz when you put hydrochloric acid
on it, and has a faint rust color. The cement holding it together is (choose one):
a. silica
b. iron oxide
c. calcite
d. none
7. On the map below, circle the area that experienced the lowest metamorphic
temperature and pressure.
Questions 8 through 10 concern the cross-section below.
8. Order the lettered
events (there are five)
from oldest to most
recent.
9. Circle an area on the
cross-section that is an
unconformity. What type of unconformity is it?
10. (3 points) The fault Q on the previous page is an example of (choose one):
a. a reverse fault
b. a normal fault
c. a strike-slip fault
which is due to (choose one):
a. compressional stress
b. extensional stress
c. shearing stress
which is related to (choose one):
a. divergence
b. convergence
c. transform motion
11. (4 points) Match the layer on the left with its origin on the right.
Vashon Till
Lake Russell
Esperance Sand
Interglacial period “Puget River”
Lawton Clay
Puget Lobe Glacier
Olympia Beds
Glacial meltwater streams
12. The pattern of the foci of aftershocks should be (choose one):
a. On the perimeter of the break area of the main quake on the fault plane
b. Within the break area of the main quake on the fault plane
c. Within the break area of the main quake off of the fault plane
d. Well away from the break area of the main quake on the fault plane
13. The seismic waves that arrive first at any given station are (choose one):
a. the P waves
b. the S waves
c. the surface waves
The waves that cause the greatest destruction to structures, however, are (choose
one):
a. the P waves
b. the S waves
c. the surface waves
14. The Seattle Fault is (choose one):
a. a thrust fault
b. a strike-slip fault
c. an inactive fault
Therefore, the Seattle Fault is capable of generating (choose all that apply):
a. tsunamis
b. liquefaction
c. landslides
Drawing – Draw an east-west cross-section of the eastern Pacific/western
North America at our latitude, from the East Pacific Rise to eastern Washington.
Include the following features for full credit:
• Indicate the west side of your sketch with a “W” and the east side with an “E”
• The three plates with their names; recall that plates are of finite thickness
and have bottom edges as well; draw the motion arrows showing which way the
plates are moving. Also, show sea level.
• The East Pacific Rise and arrows to indicate how mantle convective
currents move there
• A Cascades volcano and its magma source, including the role of fluids from
the subducting slab
• The trench and the accretionary wedge (or the mélange zone)
• Label the Olympics, the Cascades, Puget Sound and the Yakima Foldand-Thrust Belt; indicate the structures they represent
• Show the Columbia River Basalts in their correct placement
Essay section one — answer three of the following and please circle the number
of the questions chosen. Make sure your answer is in paragraph form.
15. Look at rock samples A, B and C. Determine if they are sedimentary,
metamorphic or igneous. Explain, for each sample, how you determined its
type; you cannot use “elimination” since there may be two of one type and none
of another.
16. The town of Kaimu lies 30 km (20 miles) southeast of Kilauea (a shield
volcano) on the island of Hawaii. The town itself lies in a small valley that
originates on the mountain. You are in charge of volcanic hazard reduction for
the town. Order the following volcanic hazards from most severe to least
severe, and give reasons for your ordering: a) pyroclastic flow and blast, b)
lahar, c) lava flow, and d) tephra (ash) fall. If you believe two of the hazards are
equally dangerous (or not dangerous), you should state that clearly.
17. Magnetic “stripes” are areas of seafloor with the same magnetic mineral
orientation, laid down parallel to spreading ridges. Spreading ridges are linear
features, so how are magnetic stripes that “bend” explained? Hint: Recall the
southwestern part of the Cocos Plate (on the Plate Tectonics Map of the Pacific
Basin) for similar current activity.
18. On the Cougar Mountain field trip, we saw that the Renton Formation
consisted of well-defined layers of cross-bedded light reddish sandstone, which
contained small wood fragments and leaves. Look at the diagram in Lab 5, or figure
6.13 on page 123 of the text (showing depositional environments). Which
depositional environment (be specific) represents the Renton Formation?
Explain your choice using the description of the formation’s rocks.
19. You are an anthropologist working on the question of human evolution. You
have a site where an early hominid skeleton (actual bone!) is found sandwiched
between a volcanic ash layer above the skeleton and a limestone layer below the
skeleton. You have enough research funds to numerically date one of these.
• What material would you date?
• What dating method would you use?
• Why did you not date the other materials?
20. Glacial equilibrium line altitudes (ELAs) should decrease further from
the equator. However, ELAs increase from 0° to 30° latitude. First, why should
ELAs decrease the further north or south of the equator? Second, why do ELAs
increase from 0° to 30° latitude?
Essay section two – answer one of the following and please circle the number of
the question chosen. Make sure your answer is in paragraph form, and answer
both parts of the chosen question.
21. The Nisqually earthquake of 2001 had its epicenter near Olympia. The
geology of Puget Sound is simple there; north of the epicenter is glaciallydeposited materials (like till and sand) and south of the epicenter is volcanic rock
(usually Cascades andesite or dacite). The town of Bremerton is 50 miles (80
kilometers) north of the epicenter; the town of Mossyrock is 50 miles (80
kilometers) south of the epicenter.
• Which town felt the earthquake first, and why?
• Which town felt more prolonged shaking and why?
22. In the cross-section above, the P-wave shadow zone is shown.
• Do P-waves travel through liquids? What is the evidence, shown on the
diagram, for your answer?
• The seismic wave paths shown near the earthquake’s focus are smooth curves;
the seismic wave paths shown on the other side of the P-wave shadow zone are
kinked. What change in the properties of materials that the waves travel through
explains these “kinks” in the paths?