OCN : Exam 1
15. From outside to inside, the Earth consists of a) rocky crust, brittle lithosphere, plastic asthenosphere, solid metal outer core, liquid metal inner core. b) rocky crust, rocky mantle, liquid metal outer core, solid metal inner core. c) rocky crust, liquid mantle, plastic asthenosphere, solid outer core, solid inner core. d) rocky crust, liquid asthenosphere, plastic mantle, liquid outer core, solid inner core. e) none of the above.
B
57. The Earth would probably have no continents if it did not have a) life b) an atmosphere c) oceans and subduction d) both a and b e) all of the above
C
11. The simplified reaction H2O + CO2 + CaSiO3 = CaCO3 + SiO2 + H2O represents a) weathering of silicate rocks by rain water and removal of CO2 from the atmosphere into rocks. b) photosynthesis followed by burial of some of the organic material produced. c) the reaction by which the Earth's core formed. d) The reaction that generates energy within the Sun and similar stars. e) the formation of evaporite deposits that can form salt domes and trap oil and gas.
A
27. Which of the following terms consistently describes a mid-ocean ridge? a) shallow earthquakes, basaltic volcanism, young crust, sediment absent to thin b) shallow earthquakes, andesitic volcanism, young crust, thick sediment c) shallow to deep earthquakes, andesitic volcanism, older crust, thick sediment d) shallow to deep earthquakes, basaltic volcanism, older crust, thin sediment e) no earthquakes, no volcanism, older crust, thick sediment
A
29. Continents are built by a) andesitic volcanism at subduction zones. b) basaltic volcanism at mid-ocean ridges. c) accretion of exotic terranes onto their margins. d) outgassing of volatiles from the Earth's interior. e) both a and c.
A
37. According to the State Constitution of Hawaii, beaches in Hawaii belong to a) the public b) the state government c) private landowners d) the Bishop Estate e) the Native Hawaiians.
A
42. Four elements make up 93% of Earth's mass. They are a) iron, oxygen, silicon, and magnesium. b) iron, oxygen, magnesium, and hydrogen. c) hydrogen, helium, nitrogen, and oxygen. d) iron, nickel, calcium, and aluminum. e) oxygen, nitrogen, carbon dioxide, and water vapor.
A
55. Evidence that the Earth's outer core is molten comes from a) Alfred Wegener's theory of continental drift. b) comparison with conditions on Venus. c) the s-wave shadow zone and the fact that s-waves are not transmitted by fluids. d) the location of the carbonate compensation depth in the Pacific. e) all of the above.
C
56. A record of Earth's history going back nearly 4 billion years can be found a) in deep-sea sediments b) in the ocean basins c) on the continents d) in subduction zones e) all of the above
C
7. The leading theory for the origin of Earth's Moon is a) gravitational capture of a large planetesimal. b) fission due to rapid rotation. c) impact by a large planetesimal, about the size of Mars, which spun off the Moon. d) formation in the same manner as Earth, by accretion. e) condensation from the Solar nebula.
C
13. Free oxygen in the Earth's atmosphere has been produced mainly by a) photodissociation of water and loss of hydrogen to outer space. b) change in sea level. c) formation of the Earth's core. d) photosynthesis followed by burial of organic carbon. e) nucleosynthesis in stars.
D
24. The theory of plate tectonics a) is a unifying theory for the Earth sciences. b) holds that the Earth's surface consists of a dozen or so rigid plates. c) holds that most mountain-building occurs along plate boundaries. d) holds that the lithospheric plates ride on the asthenosphere. e) all of the above.
D
28. The mid-ocean ridge is a ridge because a) a Mars-sized body collided with Earth early in its history. b) deep ocean water is cold, just above freezing. c) The ridges balance off the trenches, which are deep. d) the young, newly formed lithosphere is hot, and the ridge is produced by its thermally expanded state. e) none of the above.
D
34. Most of the sediment in the oceans, by volume, is deposited a) by organisms that have calcareous skeletons. b) by organisms that have siliceous skeletons. c) in the deep-sea trenches. d) along the margins of the continents. e) by andesitic volcanoes.
D
35. The main components of sediment on the deep-sea floor are a) biogenic, volcanogenic, and cosmogenic b) pelagic, hemipelagic, and neritic c) authigenic, hydrogenous, and hydrothermal d) calcareous ooze, abyssal clay, and siliceous ooze e) ooze, chalk, limestone, and sand
D
40.What is the approximate age of the Earth? a) 10 thousand years b) 14 million years c) 1 billion years d) 4.5 billion years e) the same as the age of the Universe.
D
45. According to the Geodynamo theory, the Earth's magnetic field originates from a) a bar magnet at the center of the Earth. b) the Solar wind. c) cosmic rays bombarding the upper atmosphere. d) convection currents within the Earth's outer, liquid iron core. e) outgassing of the planet and formation of the core.
D
46. Which of the following represents the extraordinary evidence that convinced geologists that the outrageous hypothesis of seafloor spreading was correct? a) the elevated topography of mid-ocean ridges. b) absence of sediment along the mid-ocean ridge axis. c) evidence for earthquakes and volcanism along the mid-ocean ridge axis. d) magnetic stripes on the seafloor that were symmetrical on either side of the mid-ocean ridge axis and which could be correlated globally. e) a valley along the mid-ocean ridge axis, formed by normal faulting and extension.
D
8. Unlike the other planets, the Earth has oceans of liquid water. This is because a) Earth was bombarded by water-rich comets early in its history. b) Earth inherited a primitive, water-rich atmosphere from the Solar nebula, which condensed into oceans as the Earth's surface cooled. c) Earth formed rapidly from cold, water-rich planetesimals, and this water subsequently outgassed from Earth's interior. d) Earth is the proper distance from the Sun, such that water can exist in the liquid state. e) both c) and d).
D
9. A "runaway greenhouse" refers to a) what happened on Mars b) what happened on Venus c) a process involving a positive feedback between the amount of carbon dioxide in a planetary atmosphere and the temperature of that atmosphere. d) both b) and c) e) all of the above.
D
36. The carbonate compensation depth, or CCD, is a) the depth at which calcium carbonate dissolves in the oceans. b) the depth at which calcium carbonate sediment is replaced by siliceous ooze. c) the depth at any point in the oceans where the rate of delivery of calcium carbonate is equal to the rate at which it dissolves. d) the depth above which calcium carbonate can accumulate, and below which it cannot. e) both c) and d).
E
4. Chemical differentiation refers to a) the sum of large-scale chemical and physical processes that separate material based on its chemistry. b) the processes that formed Earth's core, mantle, and crust. c) the processes that separated material that became the inner rocky vs. the outer gaseous planets. d) The processes that formed Earth's oceans and atmosphere. e) all of the above.
E
48. Which of the following is an example of an active subduction zone? a) Mid-Atlantic Ridge. b) East Pacific Rise. c) San Andreas Fault. d) Tibetan Plateau and Himalayan Mountains. e) Peru-Chile Trench and the Andes Mountains.
E
50. The scientific method involves a) making observations b) asking questions c) formulating hypotheses d) making predictions e) all of the above.
E
54. Earth's core is composed of a) solid Fe and Ni b) liquid Fe and Ni c) silicate rock that flows plastically d) basalt e) both a and b
E
6. The following are examples or characteristics of great circles: a) the equator. b) all lines of constant latitude. c) all lines of constant longitude d) The plane of the circle that passes through the center of the Earth. e) a, c, and d.
E
An hypsometric curve shows two levels on Venus and only one on Earth.
F
Beaches are normally very stable in shape and width unless disturbed by human activities
F
Earthquakes can only occur in the asthenosphere
F
In science complex theories are preferred over simple ones.
F
Oceans of liquid water are common in our Solar System.
F
On the island of Oahu, sea level is falling at present
F
Refractory elements are those that tend to form gases, even at relatively low temperature
F
Sea level changes have been modest throughout Earth's history, never exceeding more than about 10 m up or down
F
Seawalls are usually effective in preventing beach erosion
F
The Earth's mantle is entirely molten.
F
The Hawaiian Islands have formed along an active plate boundary
F
The Pacific Ocean has the highest rate of input of terrigenous sediment of any of today's oceans
F
The amount of land exposed above sea level has remained about the same for the last 600 million years.
F
The atmospheres of Earth and its nearest neighbors, Venus and Mars, are similar.
F
The crust is the same as the lithosphere
F
The four inner planets are relatively richer in volatile elements and compounds than are the four outer gas-giant planets.
F
The oceanic crust is much thicker than the continental crust
F
Venus has a similar outgassing history to Earth, and similar surface conditions
F
Worldwide, sea level is falling today
F
10. Carbon dioxide that has outgassed from Venus resides mainly in Venus's atmosphere. On Earth, carbon dioxide that has outgassed is mainly a) in rocks, as CaCO3 in limestone. b) dissolved in the oceans. c) tied up as organic matter in soils. d) stored in coral reefs. e) stored in deep-sea sediments.
A
59. Which of the following statements correctly describes crustal formation? a) Continental crust is created by wet melting of the mantle in subduction zones to produce and esite, whereas oceanic crust is formed by dry melting at mid-ocean ridges to form basalt. b) Continental crust is created by erosion in mountain belts, whereas oceanic crust is created from deep-sea sediments. c) Continental crust is formed above sea level, whereas oceanic crust is formed below the carbonate compensation depth. d) Continental crust is formed on cratons, whereas oceanic crust is formed in mobile belts. e) None of the above.
A
16. The principal of isostasy states that the Earth's surface is dominated by two levels: a) the continents and the oceans. b) the lithosphere is in gravitational equilibrium through a buoyancy mechanism, with compensation occurring in the asthenosphere. c) crust is produced by differentiation from the mantle, by upwelling and solidification of molten rock. d) if the Earth were perfectly smooth, it would be covered by nearly 3000 m of seawater. e) 25% of the continental crust presently lies below sea level.
B
17. Earth's magnetic field originates from convection currents within a) the mantle b) the liquid outer core c) the liquid inner core d) the solid inner core e) the asthenosphere.
B
2. Which of the following statements most accurately reflects current scientific thinking? a) The size of the universe is static; it has always been and will always remain so. b) The Universe is expanding but will eventually reverse and begin to contract. c) The Universe is contracting and will end in the Big Crunch. d) The Universe is expanding and will end in the Big Chill. e) None of the above.
B
20. An Atlantic-type continental margin and its offshore region consists, from land to sea,of a) shelf, slope, rise, trench b) shelf, slope, rise, abyssal plain c) shelf, slope, trench d) shelf, slope, marginal basin, abyssal plain e) either b or c
B
3. The Sun's energy comes from a) gravity b) nuclear fusion c) red-shifting d) parallax e) chemical differentiation.
B
30. Continent-continent collisions a) result when the ocean basin between them is consumed by subduction. b) cause the crust to thicken locally, as continental crust is too thick and buoyant to subduct. c) cause the subducting lithospheric slab to break off, after which it continues to descend on its own. d) can cause a reorganization of plate motions. e) all of the above.
B
31. Recent studies have shown that the main driving force for the Pacific Plate is a) ridge push. b) slab pull. c) gravity sliding. d) drag at the base. e) push by mantle plumes.
B
38. The major long-term cause of coastal erosion is a) failure of politicians to plan ahead. b) sea level rise. c) beach loss. d) building of sea walls and groins. e) continental drift.
B
39. The best place to look for petroleum in the seabed is a) in shallow seas floored by continental crust. b) in areas of thick sediment, of several km or more c) along continental margins d) in abyssal plains e) a, b, and c
B
41.Which of the following statements is true? a) Magnetic North is always the same as True North. b) Magnetic North has never varied by more than about 20 from True North. c) Magnetic North is always the same as Geographic North. d) The Earth's magnetic field is constant and unchanging. e) None of the above.
B
51. If the Sun is overhead one hour later than at some fixed point to the east of you, how many degrees are you to the west of this position? a) 5 degrees b) 15 degrees c) 20 degrees d) 25 degrees e) 30 degrees
B
58. Evidence that the Earth has two kinds of crust comes from a) seismology. b) the hypsometric curve that plots Earth surface area against its elevation. c) the Moon. d) both a) and b). e) all of the above.
B
12. The reaction CO2 + H2O = CH2O + O2 represents: a) photodissociation b) chemical weathering c) photosynthesis d) none of the above. e) all of the above.
C
18. The Earth has dry land because a) there is not enough water to cover the surface completely. b) all planets have dry land. c) it has continental crust, which rides is statically higher than oceanic crust because it is relatively thick and less dense. d) sea level has dropped throughout Earth history. e) the mid-ocean ridges push up the bottom of the seafloor, as if it were a large plastic bowl.
C
21. Atlantic-type continental margins are considered to be aseismic, or passive, because a) they lack earthquakes. b) they lie along a plate boundary. c) they lie far from a plate boundary. d) both a) and c). e) none of the above.
C
23. The continents drift because a) they "plow through" the ocean basins in response to "polflucht". b) of convection in the Earth's outer core. c) they ride passively on the lithospheric plates, which are moving relative to one another and the mantle. d) the Earth's magnetic field reverses its polarity. e) all of the above.
C
33. The three main geologic settings on Earth where active volcanoes occur are a) abyssal plains, abyssal hills, and continental margins. b) Hawaii, Iceland, and the Andes. c) mid-ocean ridges, subduction zones, and hotspots. d) convergent, divergent, and conservative plate boundaries. e) Indonesia, Japan, and eastern Australia.
C
43. The process of large-scale chemical differentiation of the Earth has produced a) the Earth's core. b) the Earth's mantle. c) continental and oceanic crust. d) the oceans and atmosphere. e) all of the above.
C
44. Evidence that Earth is still outgassing today exists in: a) input of helium-3 into the ocean from hydrothermal vents b) mantle plumes c) Yellowstone geysers d) Eruption of Mt. St. Helens e) none of the above.
C
47. Which of the following terms consistently describe a subduction zone? a) shallow earthquakes, basaltic volcanism, young crust, sediment absent to thin b) shallow earthquakes, andesitic volcanism, young crust, thick sediment c) shallow to deep earthquakes, andesitic volcanism, older crust, thick sediment d) shallow to deep earthquakes, basaltic volcanism, older crust, thin sediment e) no earthquakes, no volcanism, older crust, thick sediment
C
49. Continent-continent collisions a) result when the ocean basin between them is consumed by subduction. b) cause the crust to thicken locally, as continental crust is too thick and buoyant to subduct. c) cause the subducting lithospheric slab to break off, after which it continues to descend on its own. d) can cause a reorganization of plate motions. e) all of the above.
C
5. The Earth is relatively depleted in noble gases because a) its present mass is too small to hold them. b) they have been removed by reaction with surface rocks. c) they were vaporized and lost when the Earth melted. d) they were lost early on from the planetesimals that eventually accreted to form the Earth. e) they have never outgassed from the Earth's interior.
C
1. Which of the following is true about the scientific method? a) The scientific method is a systematic way of asking and answering questions about the natural world. b) In science, simple theories are preferred over complex ones. c) Scientific theories are always subject to challenge and may be overturned. d) Scientific theories are continuously updated as new information becomes available. e) All of the above.
E
14. Which of the following statements is true? a) On Earth, H2O is in the oceans, CO2 is in rocks, and N2 and O2 are in the atmosphere b) On Venus, H2O was lost to outer space as H2, CO2 and N2 are in the atmosphere, and O2 was never present. c) On Mars, H2O and CO2 are frozen out as ice, N2 was lost to space, and O2 was never present. d) On Venus the atmosphere is very thick whereas on Mars it is very thin. Both atmospheres are mainly CO2. e) All of the above.
E
19. Sea level can change as a result of a) change in the rate of seafloor spreading, which produces a change in the volume of the ocean basins. b) change in the volume of ice stored on land. c) local, tectonically induced vertical motions of the crust. d) change in the temperature of ocean water. e) all of the above.
E
22. Continental drift theory was initially rejected but experienced a revival in the 1950's as a result of new evidence that a) animals had crossed from Africa to South America via land bridges. b) the Earth's magnetic field had reversed polarity repeatedly in the past. c) the Earth's magnetic poles had apparently wandered through time, but the paths inferred were different for different continents. d) the Earth was rotating on its axis, which corresponds to the geographic and magnetic poles. e) all of the above.
E
25. Which of the following is a "rule" of plate tectonics? a) Continental crust is too thick and buoyant to be subducted. b) The volcanic arc always forms on the upper surface of the subducting plate. c) When continents collide with one another they tend to "stick". d) The major process driving the plates is convection in the Earth's outer core. e) Both a) and c).
E
26. The three major types of plate boundaries are a) conservative, transform, slipslide b) continental-continental, oceanic-oceanic, continental-oceanic c) divergent, convergent, conservative d) constructive, destructive, conservative e) both c) and d).
E
32. Which of the following statements about hot spots is/are true? a) They originate from plumes of unusually hot mantle that remain fixed as the plates move over them. b) They provide a means to estimate the direction of plate motion relative to the mantle. c) They represent a third geologic setting for volcanism on Earth, along with mid-ocean ridges and subduction zones. d) They can occur on land or on sea, at or away from axes of seafloor spreading. e) All of the above.
E
An informal rule in science is that extraordinary hypotheses require extraordinary evidence
T
Atolls originate as fringing reefs on volcanoes that eventually subside below sea level
T
Because seismic s-waves do not travel through liquids, the s-wave shadow zone indicates that at least part of the Earth's core is molten
T
Continental crust is too buoyant to be subducted
T
Current scientific theories suggest that the universe is 10-15 billion years old
T
Earth contains elements that were formed in a supernova explosion
T
Earth is believed to have originated by accretion from planetesimals.
T
Earth is not massive enough to retain all of its constituent chemical elements.
T
Earth's crust originated by solidification of molten rock that rose up from the mantle.
T
Free oxygen has always been an important component of the Earth's atmosphere.
T
Hotspots can occur both at plate boundaries and in the middle of plates, and both in the oceans and on the continents.
T
Latitude can be told from the declination of the Pole Star, whereas longitude requires an accurate clock.
T
Sand that lies on the beach in the summer (in most places) is often stored in an offshore bar during winter.
T
Science is a powerful way to find out about the natural world, but it has its limitations.
T
Seismic S-waves do not travel through liquids and this indicates that at least part of the Earth's core is molten.
T
The Earth is about 4.5 million years old
T
The Earth is believed to have originated by accretion from planetesimals and planetary embryos
T
The Hawaiian Islands are an example of island arc volcanism.
T
The age of the Earth is indistinguishable from that of the Moon and meteorites: about 4.5 billion years.
T
The continental crust is much thicker than the oceanic crust.
T
The deep sea is a promising place to explore for oil and gas
T
The depth of the seafloor is linearly related to the square root of its age out to about 80 million years
T
The lithosphere is rigid and brittle, whereas the asthenosphere is plastic and ductile
T
The oldest rocks from the seafloor are much younger than the oldest rocks from the continents.
T
