Possible Ring of Fire Final Exam Questions, December 20, 2006


Part I. The test will have 20 of the following questions, to be answered in a sentence or so.

1) Explain the role of gravity in the differentiation of planetary layers.
2) What are silicate rocks, and why are they significant?
3) The mean density of Earth's mantle is much greater than the density of rocks at the top of the mantle. Why?
4) Why are there seasons?
5) Why is the magnetosphere important?
6) What is radiation, and what role does it play in the cooling of the earth?
7) What is conduction, and what role does it play in the cooling of the earth?
8) Why is the asthenosphere softer and weaker than the rock above and below it?
9) What role does radioactivity play in mantle convection?
10) Why is the lithosphere stiff, rigid, and seismically "fast" compared to rock below it?
11) Why does Earth have a strong magnetic field?
12) Why are the deepest regions of the ocean not found in the middle of the ocean?
13) The average continental crust is about 40 km thick. Why is the crust beneath a mountain range like the Himalayas more than 75 km thick?
14) How does the deep water cycle differ from the surface water cycle?
15) Why can it be said that the Sun drives the hydrologic cycle?
16) What role did gravity play in the formation of the solar system?
17) How do we know that the solar system formed from the the remains of a supernova (death of a previous star)?
18) What does the Doppler shift of stars tell us about our Universe? Does this support the idea of the "Big Bang"?
19) If you go out to any random point in deep space, away from any matter, the temperature is about 2.7 degrees K. Why?
20) Why is it that Earth does not have an atmosphere that is mostly carbon dioxide, like its neighbors Mars and Venus?
21) How did the Moon most likely originate?
22) There are several NASA missions planned to visit Europa, a moon of Jupiter. Why is there so much interest in this moon?
23) Why do we think there used to be a lot of water on Mars?
24) Why would Venus be a very inhospitable place to live?
25) Why is Jupiter's moon Io the most volcanic place in the solar system?
26) What is an ionic bond?
27) What is a covalent bond?
28) Explain why diamonds at the earth's surface are an example of a metastable mineral phase.
29) How does increased pressure affect a mineral?
30) Why are glass and coal not considered minerals?
31) Please classify the following as mineral, rock, or neither. If neither, why? (ice, coal, glass, diamond, oil, granite
32) Why do intrusive igneous rocks like granite have large, visible crystals?
33) Why are magmas that are rich in silica usually more viscous?
34) Why does water play a dual role in the behavior of magma?
35) Why does a subduction zone volcano at the edge of a continent usually have an "intermediate" chemical composition (like andesite or diorite)?
36) What is the difference between how an igneous sill and dike form?
37) The inner core is more than 5000 degrees C, yet it is solid and not liquid. Why?
38) How is it that very large volcanic eruptions might alter the history of civilizations that may be far away from them?
39) Volcanic activity usually occurs at plate boundaries, but the volcanic activity at Hawaii occurs within the interior of the Pacific plate. Why?
40) What is a pillow basalt? Where does it form?
41) Why are most of the world's above-ground volcanoes found around the rim of the Pacific Ocean?
42) Why does magma form deep in subduction zones, even though the subducting slabs chill the region?
43) Why are there volcanoes in Oregon, Washington, and Northern California?
44) Why are volcanic eruptions above subduction zones often explosive?
45) The tops of many volcanoes are often covered with snow. Why can this be a deadly combination?
46) What is the difference between the geotherm and the solidus?
47) How does the mechanism of pressure release cause melting? Where would you see this?
48) Why do stratovolcanoes have steeper slopes than shield volcanoes?
49) What is a pyroclastic flow? Why is it dangerous?
50) Why are sunsets observed worldwide more dramatic following large volcanic eruptions?
51) Salt and sandstone are both sedimentary rocks. What is the difference between the way that they form?
52) Why are sedimentary rocks (like in St. Louis) often found in sandstone-limestone-shale sequences?
53) What is a fossil?
54) How do you turn limestone into marble?
55) Give an example each of brittle and ductile deformation within the Earth's crust.
56) Draw a picture of the kind of fault you would expect in a compressional region. What is this kind of fault called?
57) Draw a picture of the kind of fault you would expect in an extensional region. What is this kind of fault called?
58) What kind of geographical region would you go to today to find anticlines and synclines being formed?
59) An anticline and syncline may look the same at the surface if the surface has been eroded flat. How can you use the ages of the rocks to tell whether the fold is an anticline or syncline.
60) Why is an anticline often the best place to look for petroleum underground?
61) Describe how radioactivity can be used to determine the age of a rock.
62) How do we know the Earth is 4.57 billion years old?
63) How do we know that the outer core is liquid?
64) How is the Earth's core-mantle boundary connected with plate tectonics?
65) How do mantle plumes form?
66) How can you determine the location and size of an underground nuclear test?
67) What are the two reasons that fires are a big hazard with earthquakes?
68) What is the San Andreas fault?
69) Why is Seattle at more of a risk from devastating earthquake destruction than San Francisco?
70) What happens during soil liquefaction resulting from an earthquake?
71) What is the difference bewteen earthquake prediction and earthquake forecasting?
72) What did the Parkfield earthquake of 2004 tell us about the reliability of earthquake forecasting?
73) What is the "seismic gap" hypothesis?
74) Why is the "dispersion" (separation into separate waves) of tsunami waves deadly for people near the shore?
75) Tectonically, why did the giant 2004 Sumatra earthquake occur?
76) Why is it probable that a volcanic eruption gave rise to the legend of Atlantis?
77) How is paleomagnetism ("the history of Earth's magnetic field") used to tell the ages of rocks within the ocean seafloor?
78) Why is the heat flow (heat conducting out of the Earth through the crust) largest near mid-ocean ridges?
79) Give one example for the current location of each of (A) continent-continent collision, (B) ocean-continent collision, and (C) ocean-ocean collision.
80) Describe the vertical structure of oceanic crust. Draw a picture, if helpful.
81) What role does the force of slab pull play with respect to plate tectonics?
82) What two factors cause the magnetic "stripes" in the ocean crust?
83) Why are the plates moving and what are the main forces that affect their movement?
84) What is the best current way to measure the relative velocities of Earth's tectonics plates? On average, roughly how fast are they moving?
85) Rocks from India show evidence of widespread glaciation 250 million years ago. We know that the whole world wasn't cold because tropical jungles covered northern Africa at this time. Why was India covered with ice?
86) How are the Appalachian Mountains related to the formation of Pangea?
87) How do we know that North America has increased in size over time?

Part II: The test will have 6 of the following questions, to be answered in a paragraph or so.

1) Explain the different effects of pressure and temperature on the melting of rocks, and show the effects of this duel on different layers within Earth.
2) Imagine that this piece of paper gets flushed into the sewer and dissolves. Follow the path of a hypothetical carbon atom that makes it through the treatment plant and flows into the Mississippi River. Describe a plausible path through part of the rock cycle that will allow it to eventually end up in a tree again.
3) There are really 2 separate big-picture rock cycles: one that passes through the continental crust, and the other that incorporates the core-mantle boundary. Both cycles share a path along the oceanic plate toward and into a subduction zone, but these paths separate at the subduction zone where some rock continues downward and some melts and rises upward. Describe the path rock would take along these two cycles.
4) Describe the 3 lines of evidence in support of the Big Bang theory.
5) Discuss the formation of the earth, including the many factors that led to its melting about 4.5 billion years ago.
6) Describe the process by which a protoplanetary nebula became our solar system.
7) There are really 3 classes of planets in our solar system: terrestrial planets, gas giants, and dwarf planets (Kuiper belt objects). Explain the difference between the three. Why do they form at different distances from the Sun?
8) Describe the difference between ionic and covalent bonds. Give an example of each.
9) Explain why sodium and chlorine atoms usually form ions. Explain how they bond together to form the mineral halite.
10) Explain the many differences and similarities between the rocks granite, rhyolite, basalt, and gabbro. Use a chart if it helps.
11) Describe the three factors the determine the viscosity of a magma. Explain how these are different for an eruption at Hawaii and at a subduction zone volcano like Mt. St. Helens.
12) We see three common types of volcanism at earth's surface: at rifts and ridges (mid-ocean ridges and continental rifts), above subduction zones, and at hotspots. Explain why rock melts in each case.
13) Explain three different hazards from volcanoes. Where would you expect to find them? Give an example of each.
14) Describe how the concept of plate tectonics explains the global distribution of earthquakes. Explain where you would expect to find strike-slip, normal, and thrust (or reverse) faulting.
15) How are strike and dip used to describe the orientation of a fault? [Note: Be prepared to draw faults with different strikes and dips.] How is slip described? What kind of fault has a slip of about 0 degrees? 180 degrees?
16) What are the 3 ways that heat is transported? Explain the roles of these 3 in allowing for heat to pass eventually from Earth's core out through Earth's different layers and eventually out into space.
17) What is the cause of volcanism on Hawaii? Where does the rock come from that erupts at the surface? Why are volcanic eruptions on Hawaii much less violent than subduction zone volcanoes like Mt. St. Helens? Why are the Hawaiian Islands successively older as you travel toward the north-northwest? What does this say about the absolute motion of the Pacific plate?
18) In class, mantle convection was compared to a convecting bowl of miso soup. Explain why. Why is the analogy more appropriate for a a bowl of soup in a microwave oven as opposed to on top of a stove?
19) Earthquakes and volcanoes are both significant worldwide natural hazards. Discuss the different kinds of damage or destruction they can cause.
20) What major geologic hazards could potentially affect Seattle and the surrounding regions? What would the effects be of these hazards? How might some of the effects be lessened?
21) Earthquake prediction and forecasting have been difficult. Why is this so? What kind of precursory activity is sometimes seen before earthquakes? Explain why the Parkfield earthquake of 2004 was both a success and failure of forecasting. Why are volcanoes more easily predicted than earthquakes?
22) Describe how the concept of plate tectonics explains the bathymetry of the ocean seafloor. Include the occurrence of ridges, trenches, fracture zones, varying sediment thicknesses, and the change in depth with distance from ridges.
23) Describe 5 different lines of evidence that support the concept of plate tectonics.
24) Describe the formation of a divergent plate boundary, starting with a single continent, and ending up with an ocean.
25) Explain what the magnetic stripes on the ocean floor are, how they formed and what they tell us about the age of oceanic crust and plate velocities.
26) Describe two ways that continents grow in size over time, and two ways that continents can shrink in size over time.
27) The Mediterranean Sea, Red Sea, East African Rift, Pacific Ocean, Himalayan Plateau and Atlantic Ocean all represent different stages in the life cycle of an ocean over roughly a half-billion years. Put these examples in order of maturity from youngest to oldest, and explain the cycle.
28) Are the oldest continental rocks at the edges or the interiors of continents? Are the oldest oceanic crustal rocks at the edges or interiors of oceans? Explain why these answers are different, discussing the ways continents and oceans grow.
29) How would the east coast of North America change if the oceanic segments of the plates that make up the Atlantic Ocean basin began to subduct? How would it change if the Atlantic Ocean lithosphere subducted completely?
30) Explain the effects of a volcanic eruption on climate for both the short term and long term. Do these affect climate the same way? Give an example of how a volcanic eruption has affected human society.
31) Describe three significant effects on the history of humanity due to the rising sea levels that accompanied the ending of the last ice age.
32) Explain how changing climates that caused the famines in Europe and flooding in Asia were connected to the plague that hit Europe in the 1340s.
33) Explain why Lief Ericsson and the Vikings were expanding into North America at the same time that the Mayan and American Southwest cultures were dying. What does this suggest for the near future?