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GEOL180 - Introduction to Oceanography EXAM 1
Figure 1:
1. Which of the following has the least average sediment thickness?
a. continental shelves b. continental slopes c. continental rise d. deep-ocean floor
2. Calcareous sediments are found in deep-sea areas, always below a depth of about 4500 m
a. True
b. False
3. Siliceous sediments will only be preserved on the sea floor in regions where there is high biological productivity
in the overlying water column.
a. True
b. False
4. The theory of continental drift was first proposed by
a. James Cook
b. Karl Marx
c. Alfred Wegener
d. Charles Darwin
5. The Challenger Expedition marked the beginning of descriptive oceanography.
a. True
b. False
6. The earth turns on its axis about
a. 15 degrees in 1 hour
c. 4 degrees in 1 hour
b. 4 degrees in 1 minute
d. 15 degrees in 1 minute
7. Which one of the following processes contributes least to sediments in the ocean?
a. volcanic activity
b. weathering and erosion of rocks
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c.
d.
e.
chemical processes that concentrate salts
hydrothermal activity at mid-oceanic ridges
decay of once-living organisms
8. The average depth of the ocean is about
a. 4000 m
b. 3900 km
c. 3899 mi
9. Water on the surface of the Earth was derived from
a. Mantle rock
b. outer space c. answers a and b are correct
10. The largest and deepest ocean is the Pacific Ocean
a. True
d. 11,000 m
d. none of the above
b. False
11. The world's most intense earthquakes occur at which type of plate boundary?
a. Convergent
b. Divergent
c. Transform
d. extinct paleo-margin
12. The most likely mechanism causing the crustal plates to move is thought to be produced by
a. convection cells in the mantle
b. oceanic currents
c. rotation or the earth
d. tidal forces
13. Sediments in the oceans can be classified based on
a. size
b. location
c. sources and chemistry
d. all of the above answers are correct
14. Magnetic stripes on the seafloor are created
a. at subduction zones
b. at mid-ocean ridges
c. within abyssal plains
d. on continental margins
15. Plates move horizontally (slide) past each other along
a. transform faults
b. convergent plate boundaries
c. divergent plate boundaries
d. island arc systems
16. Seafloor spreading is continuing at a rate of approximately
a. 1 to 10 cm/yr
b. 1 to 10 m/yr
c. 1 to 10 km/yr
17. The lithosphere is composed of the
a. continental crust
only
c. the crust and the upper rigid mantle
d. 1000 m/yr
b. oceanic crust only
d. the crust and the whole mantle
18. Rivers supply ¼ of all terrigenous sediments to the oceans
a. True
b. False
19. The inner core of the earth is liquid whereas the outer core is solid.
a. True
b. False
20. Oceanic crust is denser than continental crust.
a. True
b. False
21. Ridges are spreading centers where new oceanic crust is created.
a. True
b. False
22. Which of the following is characteristic of oceanic-oceanic convergent plate boundaries?
a. volcanic island arcs
b. andesitic volcanoes
c. mid-ocean ridges
d. fracture zones
23. The continental masses are often more than three billion years old while seafloor is rarely older than 200 million years
because:
a. the break up of Panthalassa has destroyed all ancient seafloor
b. all the older seafloor is layered under the present continental crust
c. new seafloor eventually subducts and melts in deep-sea trenches; this process rarely takes longer than 200 million years.,
d. older seafloor is destroyed by P and S waves
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24. Fine particles of sediment can be classified as: sand, silt or clay. These particles are defined by _________.
a. their origin
b. their size
c. their color
d. the rate at which they accumulate on land
25. Heat flow measurements indicate that convection cells must
a. rise below ridges and sink below trenches
b. rise below trenches and sink below ridges
c. rise below ocean basins and sink below continents
d. rise below continents and sink below ridges
26. Which one of the following type of sediments is found in the oceans in very low concentration (amounts)?
a. biogenous
b. cosmogenous
c. hydrogenous
d. lithogenous
27. Which one of the following is the plate boundary where oceanic crust forms?
a. convergent
b. divergent
c. transform
d. all of the above
28. Which one of the following best describes a person who studies and observes wave dynamics, currents, and oceanatmosphere interactions?
a. Marine geologist
b. Chemical oceanographer
c. Marine biologist
d. Physical oceanographer
29. What type of plate boundary exists along the west coast of South America?
a. Ocean/Continent b. Ocean/Ocean c. Continent/Continent
d. Transform/Conform
e. Divergent/Transform
30. The farther from the spreading center, the ___________ oceanic floor in that spot.
a. younger and less dense
b. older and more dense
31. The average temperature of the world’s ocean is
a. 0°C
b. -18.0°C
c. 18.0°C
d. 4°C
e. -4°C
32. Hot spots in the mantle, can not be explained by basic mantle convection theory.
a. True
b. False
33. The cool, solid crust and upper mantle “float” over the deformable mantle due to
a. expansion of the warmer lower mantle
b. buoyancy of the rotating outer core
c. isostatic equilibrium
d. gravitational pull of the moon
34. Which one of the following is NOT a lithogenic (land derived) sediment?
a. silt
b. clay
c. sand
d. calcareous ooze
35. The Mid-Atlantic Ridge system is covered by a thick layer of surface sediment deposited slowly over a long period of time.
a. True
b. False
36. Which kind of plate movement is responsible for the formation of the Rift Valley of East Africa?
a. Divergent oceanic crust
b. Divergent continental crust
c. Oceanic/continental collision
d. Continent/continent collision
37. The asthenosphere is Earth’s cool, rigid, outer layer which is 100-200 kilometers thick; whereas, the lithosphere is the hot,
partially melted, slowly flowing layer of upper mantle below the asthenosphere.
a. True
b. False
38. Longitude is given in degrees
a. east and west of the equator
c. east and west of the prime meridian
b. north and south of the equator
d. north and south of the prime meridian
39. If a clock is set to Greenwich Mean Time (GTM) and the sun is observed to reach its zenith at 10:00AM, what is the
longitude?
a. 30 West
b. 30 East
c. 60 West
d. 60 East
e. 0 you are on the Prime Meridian
40. The trench system located just off shore of the Hawaiian Islands is one of the deepest features within the Pacific Ocean.
a. True
b. False
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41. During the Southern Hemisphere's summer
a. the Earth is closest to the sun
c. the Sun stands directly above the equator
b. the Earth is furthest from the sun
d. the Sun stands directly above 23.5°N latitude
42. Profiling and mapping the ocean bottom depends on an array of depth measurements. The most frequent technique for
measuring ocean depth employs what medium?
a. light in the form of laser beams
b. lead weight at the end of a long line
c. sound waves transmitted by a transducer
d. pressure sensors dragged along the bottom
Figure 2: REFER TO DIAGRAM FOR QUESTIONS 43 – 46.
43. Does the figure represent a passive or an active continental margin?
a. Active margin
b. Passive margin
c. This figure does not show a continental margin
44. The Continental Shelf is
a. A
b. B
c. C
d. D
e. E
45. Turbidity currents transport sediment from
a. F to E
b. D to E
c. C to A
d. A to D
46. Location C represents the continental ________
a. rise
b. slope
c. shelf break
d. shelf
e. breakfast
47. Which one of the following is best associated with tectonic trenches?
a. convergent plate boundaries
b. divergent plate boundaries
c. transform plate boundaries
d. b & c
48. ______________ is a mountainous chain of young basaltic rock at the active spreading center of an ocean.
a. An oceanic ridge
b. A continental margin
c. A subduction zone
d. A trench
49. Abyssal plains are flat featureless expanses of sediment-covered ocean floor found in nearly all the world’s
oceans.
a. True
b. False
50. A flat-topped seamount eroded by wave action is called
a. abyssal volcano
b. abyssal hill
c. guyot
d. tablemount
51. Figure 1 was generated using
a. echo sounding
b. LIDAR
c. Multi-beam
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d. Satellite altimetry
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