Oceanography Practice Exam I

Earth Origins, Oceanography History, Plate Tectonics, and Seafloors

Note: 1) The actual midterm will consist of approximately 60 to 70 questions.

2) Many of the questions on the midterm will come from this practice test.

Section I. True or False – Directions: Answer true or false to the following questions or statements. Mark "a" for True and "b" for false on your Scantron sheet.

1. Of all the planets in the solar system, the Earth is the only planet to have large quantities

of liquid water on its surface.

a.	True
b.	False

2. The average height of the continents above sea level is greater than the average depth of

the ocean.

a.	True
b.	False

3. The Earth has always had an atmosphere with the composition as it has today.

a.	True
b.	False

4. The Earth has always had an atmosphere about as dense as it has today.

a.	True
b.	False

5. Humanity did not spread to virtually all the inhabitable areas of the Earth until after the

European voyages of discovery in the late 1400s and early 1500s.

a.	True
b.	False

6. The first awareness of the spherical shape of the Earth developed in Europe around 1450

with the work of Henry the Navigator.

a.	True
b.	False

7. Radiometric dating works by measuring the rate of decrease in the radioactivity of

naturally radioactive materials.

a.	True
b.	False

8. Most of the future deep-ocean research being planned by oceanographers involves

sending human pilots and observers to the greatest ocean depths in vehicles like Alvin,

Trieste, and Shinkai-6500.

a.	True
b.	False

9. The main contributions of Chinese voyaging to marine science was the compass,

battened sails, and watertight hull compartmentalization.

a.	True
b.	False

Section II. Multiple Choice: Directions: Identify the letter of the choice that best completes the statement or answers the question.

10. Earth is about

a.	6,000 years old.
b.	4.6 billion years old.
c.	4.6 million years old.
d.	40 billion years old.
e.	400,000 years old.

11. Other than the hydrogen atoms that are found in water, where were the atoms thatmaker up seawater formed? I don't mean where were they stored through the Earth's early "childhood," I mean where were the atoms heavier than hydrogen actually constructed?

a.	In the Earth's upper atmosphere.
b.	Deep within the Earth while it was forming.
c.	In a star or stars before there even was an Earth.
d.	At the instant of the "big bang".
e.	At the junction between the atmosphere and space.

12. About what percentage of the Earth's surface is covered by water?

a.	71%
b.	90%
c.	66%
d.	75%
e.	82%

13. About what percentage of the water on or near the Earth's surface is contained in the ocean?

a.	55%
b.	75%
c.	85%
d.	97%
e.	100%

14. In the scientific method, scientific theories

a.	must be tested and verified by observations.
b.	must be verified by the leading authorities in the field.
c.	must be consistent with previous, universally accepted scientific concepts.
d.	must be consistent with the fact that the ocean is of great age.
e.	are accepted as absolute fact until proven otherwise.

15. Life on Earth most probably evolved

a.	on land.
b.	in the ocean.
c.	in space.

16. The condensation theory proposes that our solar system formed from a:

a.	single accreting disc (flat cloud) of debris, dust and gas.
b.	set of individual, separate discs.
c.	larger star that split into sections.
d.	larger planet that split into fragments.

17. The ocean originated from:

a.	Volcanic gases.
b.	Radioactive heating of the Earth's interior, and the heating of the surface by meteorites striking and melting the outer icy layers of the Earth.
c.	Capture by the Earth's gravity of water from space via comets.
d.	a and c only.

18. Evidence suggests the universe began about 15 billion years ago in a

a.	slow accretion of atoms.
b.	very large galaxy.
c.	cataclysmic explosion of energy and matter.
d.	protostar.
e.	supernova.

19. Until recently, many scientists were tentative in their acceptance of the theory of the

chemical evolution of life on Earth. What has changed their minds?

a.	The discovery of organic molecules in space.
b.	The discovery of organic molecules at geothermal vents on the deep seafloor.
c.	Experiments in which organic molecules were synthesized in chambers replicating a hypothetical early Earth environment.
d.	All of the above.

20. Life could almost certainly not originate anew on this planet today. This is because:

a.	Green plants have filled the atmosphere with oxygen, a compound that can disrupt unprotected large molecules.
b.	Ozone now blocks much ultraviolet radiation from reaching the Earth's surface, depriving molecules one of the sources of energy needed for polymerization.
c.	Micro-organisms present on the Earth and in the ocean would gladly scavenge any large organic molecules that might form.
d.	All of the above.

21. Our position within the galaxy is:

a.	At the center.
b.	In a spiral arm, surrounded by dust and gas.
c.	Above the polar axis.
d.	At a vast distance from the galaxy itself.
e.	We're not in a galaxy.

22. The first life forms on Earth arose:

a.	More than 3.5 billion years ago.
b.	At the same time as the formation of the Earth.
c.	Relatively recently -- about 250,000,000 years ago.
d.	About 10,000 years ago.

23. Which hemisphere of the Earth contains the greater proportion of ocean surface?

a.	Northern.
b.	Southern.
c.	Both about equal.

24. What will happen to the Earth?

a.	Any day now, it will disappear as the sun becomes a supernova.
b.	In about 5 billion years, the sun will become a supernova, and our descendants (if any) will fry.
c.	In about 5 billion years, the sun will gradually begin to swell, and our descendants (if any) will be roasted.
d.	In about 5 billion years the sun will cool and our descendants (if any) will all freeze to death.

25. The ocean continues to grow slowly in volume. Most of the 0.1 cubic kilometer (0.025

cubic mile) of new water being added annually to the ocean comes from:

a.	outer space.
b.	conversion of seafloor rocks into water by bacteria.
c.	within the Earth as volcanic steam.
d.	from the combustion of oil and natural gas.

26. If we had to make a selection, which of these people would probably be given the title

of "first ocean scientist?"

a.	Matthew Maury
b.	Captain James Cook
c.	Christopher Columbus
d.	Wyville Thompson (of the Challenger expedition).
e.	Ben Franklin

27. John Harrison's invention of the chronometer was important because:

a.	it enabled sailors to calculate local time.
b.	it allowed the calculation of latitude after weeks at sea.
c.	it allowed the calculation of longitude after weeks at sea.
d.	it was used to calibrate navigational tools.
e.	the devices were very valuable and were considered works of art.

28. If selections were to be made, which of these voyages would qualify as the first 100% pure scientific oceanographic expedition?

a.	Columbus' 1496 trip.
b.	The Challenger expedition.
c.	Benjamin Franklin's first voyage across the Atlantic to take up his post as American Ambassador to France.
d.	Captain Cook's voyage to Tahiti in the ship Endeavour.
e.	The Chinese voyages undertaken during the Ming Dynasty.

29. The future of oceanographic research appears to lie:

a.	With single, isolated individuals working alone.
b.	With epic voyages.
c.	With the great private, institutional, and national oceanographic institutions.
d.	With the navies of the world.

30. Long-range ocean travel was first under taken by the _________, later by the _________,

and last by the _________. (Select the proper chronological order.)

a.	Europeans/Polynesians/Scandinavians (=Vikings)
b.	Europeans/Scandinavians/Polynesians
c.	Polynesians/Europeans/Scandinavians
d.	Scandinavians/Polynesians/Europeans
e.	Polynesians/Scandinavians/Europeans

31. Polynesian navigators depended on _____________ for accurate navigation.

a.	luck.
b.	stars, clouds, and the flight direction of birds.
c.	the appearance and taste of seawater.
d.	wave direction and shape.
e.	all of these things, and more.

32. Captain James Cook accomplished all of these tasks except:

a.	First European to contact the Hawaiian Islands.
b.	First to circumnavigate the world near Antarctica.
c.	Made three major voyages of discovery.
d.	Mapped the coasts of Australia and New Zealand.
e.	First European to explore the South Pacific.

33. Who discovered North America?

a.	Columbus
b.	the native Americans
c.	The Chinese Admiral Zheng
d.	Bjarni Herjulfsson
e.	Eratosthenes of Cyrene

34. In the original Greek conception, oceanus was:

a.	Earth.
b.	the Mediterranean Sea.
c.	an imaginary concept.
d.	a great flowing river.
e.	none of the above.

35. Matthew Maury is known primarily for:

a.	his co-discovery of gold at Sutter's Mill in California, triggering the gold rush and subsequent large-scale use of shipborne passenger transportation.
b.	being the first person to sense the worldwide pattern of surface winds and currents, and to base sailing directions on this knowledge.
c.	interpreting the scientific information coded in Captain Cooks private notebooks.
d.	founding the United States Naval Academy at Annapolis, Maryland.
e.	co-writing, with Alfred Thayer Mahan, The Influence of Sea Power Upon History (1890).

36. The first scientific expedition to use an echo sounder occurred during the:

a.	late 1700's
b.	early 1800's
c.	late 1800's
d.	early 1900's
e.	late 1900's

37. Glomar Challenger is known mainly for:

a.	being the first modern scientific survey ship to circumnavigate the globe.
b.	being the first nuclear powered scientific research vessel.
c.	being owned and operated simultaneously by four governmental agencies.
d.	taking the first complete cores of deep-sea sediments.
e.	sinking in 1983 under mysterious circumstances.

38. At the present time, oceanographic research is primarily the province of:

a.	private individuals, privately funded.
b.	private individuals, funded through national or local grants.
c.	private corporations, privately funded.
d.	academic institutions or governmental agencies, publicly funded.
e.	private corporations, publicly funded.

39. TOPEX/Poseidon is:

a.	the name of a Greek ocean god.
b.	an agency within NOAA.
c.	the code name for the U. S. Navy's ocean research program.
d.	a federal program to fund oceanographic research.
e.	a joint French - U.S. satellite (and associated consortia) devoted to oceanic research.

40. What is the name of the outermost solid layer of the Earth?

a.	hydrosphere
b.	lithosphere
c.	asthenosphere
d.	outer core
e.	none of the above

41. About how many kilometers (miles) is it from the Earth's center to the outer edge of the outer core?

a.	12,523 kilometers (7,827 miles)
b.	3,486 kilometers (2,167 miles)
c.	1,264 kilometers (790 miles)
d.	2,880 kilometers (1,800 miles)
e.	35 - 72 kilometers (22 - 45 miles)

42. Here are five lists of elements. Which list represents the main components of the

Earth's crust?

a.	oxygen, uranium, thorium
b.	oxygen, silicon, uranium
c.	oxygen, silicon, aluminum
d.	iron, aluminum, carbon
e.	iron, hydrogen, oxygen

43. The core of the Earth is composed primarily of:

a.	uranium
b.	nickel
c.	metallic hydrogen
d.	iron
e.	lead

44. One cubic meter of which of is the most dense?

a.	seawater
b.	granite rock
c.	basaltic rock
d.	seabed sediment
e.	mantle

45. As you know, Earth is layered inside. The layers have different sizes and densities.

How do geologists knows this?

a.	From drilling and digging down into the various layers.
b.	From observing the characteristics of lava and gas issuing from volcanic vents.
c.	From observing the transit times through the Earth of waves generated by large earthquakes.
d.	From comparisons with drill cores taken by robot spacecraft on Mars and Venus.
e.	None of these.

46. Why is the inside of the Earth still hot?

a.	Because the outer layers have prevented the escape of heat trapped during the planet's initial formation, and no new heat has been formed.
b.	Because the decay of large radioactive elements is creating heat in the Earth's inner layers.
c.	Because a nuclear process like that found in stars is at work in Earth's interior.
d.	Because huge quantities of oil and natural gas occasionally burn deep within the Earth.
e.	Actually, the inside of the earth is quite cool; it's only the outer layers that are still hot, and this heat is caused by the sun.

47. What do these things have in common: Paleomagnetism, seafloor spreading, Pangaea, Wadati-Benioff zones, transform faults, fracture zones, seamount chains, Pacific hotspots.

a.	They are all used to study earthquakes.
b.	They were discovered in the Challenger expedition.
c.	They are used to investigate the potential for undersea mining and mineral resource exploitation.
d.	They are used to predict earthquake activity and warn people of imminent danger.
e.	They are involved with the theory of plate tectonics.

48. When a substance is resting in buoyant equilibrium, moving neither up nor down:

a.	It weighs less than the water surrounding it.
b.	It displaces a volume of water equal in weight to its own weight.
c.	It displaces a volume of water which weighs slightly more than its own weight.
d.	It displaces a volume of water which weighs slightly less than its own weight.
e.	It weighs more than the water surrounding it.

49. An example of an object in buoyant (or isostatic) equilibrium would be:

a.	An ice cube floating in a glass of water.
b.	A continent "floating" on heavier material below.
c.	A table standing on a concrete floor.
d.	A person standing on a gravel driveway.
e.	a. and b. above.

50. At which of these locations is the Earth's crust thickest?

a.	Beneath Denver, high in the Rocky Mountains.
b.	Beneath Los Angeles, at the Pacific coast.
c.	Beneath Washington, D.C., on the trailing edge of the continent.
d.	Beneath the ocean floor 2,000 kilometers south of Honolulu.
e.	The crust is about the same thickness all over the Earth.

51. Which type of crust is made largely of silicon, magnesium, and iron?

a.	Granitic rock (sial)
b.	Basaltic rock (sima)

52. Which type of crust makes up the actual deep seafloor (beneath the sediments)?

a.	Granitic rock (sial)
b.	Basaltic rock (sima)

53. Which type of crust is the denser of the two?

a.	Granitic rock (sial)
b.	Basaltic rock (sima)

54. Which type of crust comprises the bulk of the continents?

a.	Granitic rock (sial)
b.	Basaltic rock (sima)

55. Which of these is most abundant on or in the Earth?

a.	mantle material.
b.	granite rock
c.	liquid water
d.	basalt
e.	inner core

56. Why is the inner core a solid?

a.	Because it is so hot.
b.	Because it is under tremendous pressure.
c.	Because of a chemical reaction with the outer core.
d.	Because it is composed mainly of iron and nickel.
e.	It is not a solid.

57. Would you agree that the position of the true geological edge of a continent is almost always the same as the position of its shoreline?

a.	agree (yes)
b.	disagree (no)

58. A "mystery" in our understanding of plate tectonics has been, until recently, the nature of the power source capable of moving the plates and the continents embedded within them. Recent evidence indicates the power source to be:

a.	The readjustment of the surface to continual shrinking of the whole Earth.
b.	Convection currents within the Earth's mantle is moving the plates.
c.	The action of ocean currents is dragging along the seafloor, causing the seafloor and the continents to move.
d.	the continual vibration from earthquakes and volcanoes slowly moves the continents equatorward under the influence of centrifugal force.
e.	The whole business is quite new, actually, having been triggered by H-bomb tests in the Pacific in the mid-1950s.

59. If two oceanic plates collide at a relatively fast speed, and one is much older and cooler (therefore denser) than the other, what will probably happen?

a.	A trench will form.
b.	Continental mountains will form.
c.	Large earthquakes will occur.
d.	a and c.
e.	b and c.

60. Land-based evidence for plate tectonics can be seen in:

a.	the distribution of Glossopteris flora and fauna.
b.	evidence of ancient glaciations.
c.	the alignment of mountain ranges.
d.	the correlation of rocks in now widely separated continents.
e.	all of these.

61. The youngest seafloor rocks are found:

a.	nearest the continental slopes.
b.	near the rift valleys of the mid-ocean ridges.
c.	beneath the deep sea trenches.
d.	evenly distributed over the ocean basins.
e.	underlying the continental shelves.

62. The magnetic striping of the seafloor is considered evidence of seafloor spreading and

a.	subduction down the rift valleys.
b.	spreading centers in the trenches.
c.	changes in the Earth's axis of rotation.
d.	periodic reversals in the polarity of the Earth's magnetic field.
e.	periodic collapses of the Earth's gravitational field.

63. The Earth's oldest rocks are found:

a.	In the deepest part of the flat ocean bottom.
b.	At the mid-ocean ridges.
c.	On volcanic islands like Hawaii.
d.	In the trenches.
e.	At the cores of the continents.

64. New crust is being generated:

a.	In the deep trenches.
b.	In submarine canyons.
c.	In the rift valleys of the mid-ocean ridges.
d.	At the centers of large continents.
e.	In all of these places.

65. The force driving the crustal plates is believed to be:

a.	Magnetism.
b.	Gravity.
c.	The pull of the sun and the moon.
d.	Deep water currents pulling on the ocean basins.
e.	Convection cells in the upper mantle and the tug of the descending plates.

66. Oceanographers believe the breakup of Pangaea occurred about:

a.	1 million years ago.
b.	10 - 25 million years ago.
c.	190 to 225 million years ago.
d.	750 million years ago.
e.	2 billion years ago.

67. Which of the following statements does not correctly describe subduction zones?

a.	They are belts of deep-focus earthquakes.
b.	They are sites where crustal plates are diverging or pulling apart.
c.	They are marked by the presence of deep-sea trenches.
d.	They are zones where old seafloor descends into the crust and mantle.

68. The mid-ocean ridges are recognized as:

a.	subduction zones.
b.	transform or lateral plate boundaries.
c.	divergent plate boundaries.
d.	convergent plate boundaries.

69. Analysis of plate motion suggests:

a.	California is going to sink into the Pacific any day now.
b.	Part of California west of the San Andreas Fault is moving northward.
c.	Part of California and Baja California are moving southward into the Peru Trench.
d.	Southern California is being subducted into the Malibu Trench.

70. Roughly how fast do most lithospheric plates move?

a.	About 3 kilometers per hour.
b.	About 3 kilometers per thousand years.
c.	About 3 centimeters per hour.
d.	About 3 centimeters per year.
e.	About 3 centimeters per million years.

71. The rigid outermost layer of the Earth is called:

a.	The asthenosphere.
b.	The lithosphere.
c.	The mantle.
d.	The Mohorovicic discontinuity.
e.	The outer core.

72. Ophiolites are:

a.	fragments of dense oceanic crust contained in terranes.
b.	bits of fossilized worms useful in dating marine sediments.
c.	young, serpent-shaped rocks formed at subduction zones.
d.	fragments of meteorites lying on the seabed.
e.	formations comprising more than half the solid ocean floor.

73. Although 99% of the ocean floor is unexplored, have people reached essentially the deepest spot in the ocean and returned safely to the surface?

a.	Yes, and just recently (in 1997).
b.	Yes, but it was some while ago, in the 1950s.
c.	Yes, and it was a French expedition led by Jacques-Yves Cousteau's son Jean-Michel.
d.	No, not yet, though a trip is now being planned.
e.	No, and such a trip is not considered possible.

74. A turbidity current is:

a.	A fast surface current of water that runs parallel to beaches and that causes a rapid decrease in water clarity.
b.	The cause of mid-ocean maelstroms (whirlpools).
c.	A phenomenon associated with violent atmospheric storms at sea.
d.	Something that always occurs at river mouths in shallow water, but does not extend into water more than 50 meters (165 feet) deep.
e.	None of the above.

75. The average width of the continental shelves is about ____ kilometers (____ miles).

a.	16 (10)
b.	35 (22)
c.	67 (42)
d.	100 (160)
e.	800 (1,280)

76. Submarine canyons occur:

a.	At the part of an ocean basin nearest the poles.
b.	At the part of an ocean basin nearest the equator.
c.	Near the edges of ocean basins associated with continental shelves and slopes.
d.	At the center of an ocean basin, at the edges of the mid-ocean ridge.
e.	On the edges of trenches.

77. The continental shelf

a.	is very narrow on the East Coast of the United States.
b.	is a steeply dipping zone dropping off to the deep seafloor.
c.	is a featureless plain unlike the neighboring continent.
d.	is a gently sloping platform with a variable landscape, including submarine canyons.
e.	all of the above.

78. Which of the following statements accurately describes passive continental margins?

a.	They are regions of bordered by oceanic trenches.
b.	They are characteristic of the margins of the Atlantic Basin.
c.	They are areas of frequent earthquakes and volcanoes, where crustal plates are converging or are in collision.
d.	They are areas where crustal plates are actively moving apart.
e.	They are usually different in topography from the adjoining coast.

79. The transition between the shelf and the deep seafloor is

a.	the littoral zone.
b.	the continental slope and rise.
c.	the abyssal plain.
d.	the mid-ocean ridge.
e.	the submarine canyon.

80. Submarine canyons are

a.	found worldwide, on all kinds of shelves.
b.	steep-walled and narrow.
c.	cut into firm rock.
d.	cut into the shelf and may extend almost to the shore.
e.	all of these.

81. The origin of deltas is related to:

a.	glacial deposition and the formation of moraines.
b.	river deposition of sediments eroded from continents.
c.	glacial erosion and the formation of troughs and fjords.
d.	volcanic activity in coastal regions.
e.	biological activity of corals, cyanobacteria, and small shelled organisms.

82. The great heaps of unconsolidated sediment at the base of the continental slope are known as:

a.	the continental rise.
b.	the abyssal hills.
c.	the abyssal plains.
d.	the mid-ocean mountains.
e.	the mid-ocean ridge.

83. The origin of submarine canyons is not well understood, but most likely

a.	is erosional, started by streams during periods of sea level lowering.
b.	is tectonic, and represents down-folds of rock within the continental shelf.
c.	is organic, resulting from the activities of burrowing organisms.
d.	is glacial, the work of glaciers depositing rock debris on the shelf.

84. The trailing edge of a moving continental mass is most likely to exhibit features associated with

a.	frequent earthquake activity.
b.	active continental margins.
c.	widespread volcanism.
d.	passive continental margins.

85. Active continental margins are located

a.	along the east coast of the United States.
b.	along the east coast of South America.
c.	on the west coasts of both North and South America.
d.	all around Africa.

86. The landscape of the deep seafloor would best be described as

a.	a featureless plain.
b.	a smooth descent with the deepest portions farthest from land.
c.	similar in rock type, sediment thickness, and erosional processes to those found on the land.
d.	having ridges, trenches, seamounts, and other features different from those found on land.

87. The characteristics of deep trenches indicate

a.	they are erosional features similar to the Grand Canyon in Arizona.
b.	they are deep, elongated creases in the seafloor where oceanic crust is being subducted.
c.	they are glacial troughs dating back to the Ice Age.
d.	they are erosional canyons cut by turbidity currents.

88. Mid-ocean ridge mountain systems, like that running down the middle of the Atlantic,

a.	are similar in origin to the Alps, the Rockies, and the Appalachians.
b.	are composed of folded and faulted marine sedimentary rocks.
c.	are constructed of normal fault-bounded blocks of volcanic basalt.
d.	are similar in size and composition to most continental mountains.

89. The islands bordering the deep-sea trenches

a.	result from a series of quiet, continuous basaltic eruptions.
b.	are accumulations of sediments on the margins of the trenches.
c.	are formed from the activities of coral and other organisms.
d.	are explosive volcanoes that emit andesite lavas.

90. The deepest parts of the Pacific Basin are located:

a.	in the center, surrounding the island of Hawaii.
b.	in the eastern part of the basin, off North America.
c.	in the rift valley of the East Pacific Rise.
d.	near the margins of South America, Japan, and the Mariana's Islands.

91. Hydrothermal springs seem to be located near:

a.	passive continental margins.
b.	active areas of seafloor spreading.
c.	the edges of the deep sea trenches.
d.	the margins of the Hawaiian chain.
e.	on the abyssal plains.

92. In general, continental shelves tend to be wider in the

a.	Pacific ocean, because its margins tend to be active.
b.	Atlantic ocean, because its margins tend to be active.
c.	Pacific ocean, because its margins tend to be passive
d.	Atlantic ocean, because its margins tend to be passive.

93. An analysis of the sequential breaking of transatlantic telephone and telegraph cables led to a better understanding of

a.	the distribution of submarine trenches.
b.	the composition of sediments.
c.	turbidity currents
d.	hydrothermal vent communities.
e.	the size of the ocean.

94. Which is greater, the average height of the continents or the average depth of the ocean?

a.	the average height of the continents.
b.	the average depth of the ocean.

95. Which is greater, the height of the world's tallest mountain or the depth of the world's greatest trench?

a.	the height of the mountain (Mt. Everest).
b.	the depth of the trench (Challenger Deep).

96. The oozes on the seafloor mostly consist of:

a.	boulders and cobbles from glaciers oozing off the land.
b.	bones and teeth of bottom-dwelling fishes.
c.	fine muds washed down the continental slope to the seafloor.
d.	microscopic hard parts of single-celled surface living organisms.
e.	treated sewage from urban areas.

97. Which of the following metals is also found in manganese nodules:

a.	iron.
b.	uranium.
c.	lithium.
d.	silver.
e.	gold.

98. Underlying the unconsolidated pelagic sediments of the seafloor are:

a.	Basalt pillows and other mafic basement rocks.
b.	Granite boulders.
c.	Glacial deposits left from the Ice Age.
d.	Ancient remnants of sunken continents.

99. Large volumes of bottom sediments may be transported long distances by

a.	storm waves.
b.	icebergs.
c.	tidal action.
d.	turbidity currents.

100. Carbonate sediments are rare in deep sea sediments because:

a.	The organisms providing shells do not live in the deep sea.
b.	The abundance of muds and clays cover the carbonate shells.
c.	The carbonate shells dissolve in deep water.
d.	The organisms do not live beyond the edge of the continental shelf.

101. Most of the floor of the North Pacific Ocean is covered with:

a.	foraminiferan ooze.
b.	windblown dust and sand.
c.	red and brown clays.
d.	diatom ooze.

102. Oozes are.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

103. The sediment that covers the greatest area of seabed.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

104. The most abundant sediment in the ocean.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

105. Generated in place, on the spot where we find them.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

106. Of organic origin; i.e., made by organisms.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

107. Which sediment type deposits on the ocean bottom from continents via rivers.

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

108. Which sediment type is of extraterrestrial origin?

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

109. Which sediment type can be used to learn about seabed age and history?

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

110. Which sediment type sometimes are made of glass?

a.	Terrigenous sediments.
b.	Biogenous sediments.
c.	Hydrogenous (or authigenic) sediments.
d.	Cosmogenous sediments.
e.	All of these.

111. In volume and quantity, most marine sediments are associated with:

a.	the edges of the deep trenches.
b.	the deep sea floor away from the continental slopes.
c.	seamounts.
d.	mid-ocean ridges.
e.	the continental slopes and rises.

112. In the process of lithification, sediments:

a.	are subducted into the mantle at a deep trench.
b.	are converted into solid rock.
c.	slip into the center of the mid-ocean ridges and become new seafloor.
d.	are uplifted to form the edges of continents.
e.	are uplifted to form high mountains like Mt. Everest.

113. Select the finest particles in this list:

a.	sand.
b.	silt.
c.	clay.
d.	granules.

114. Scientists can derive information about __________ from observing deep ocean cores:

a.	basin age
b.	mineral resources
c.	water temperature in years past
d.	the history of life in the upper layers of water
e.	(All of the above.)

115. Very small particles sometimes fall surprisingly quickly from near the ocean surface to the seabed, thus avoiding being carried great lateral distances by currents. This is possible because

a.	the particles, though tiny, are very heavy and fall quickly.
b.	the particles adhere to large particles and fall with them.
c.	the particles are compressed in the fecal pellets of small marine animals.
d.	the particles resist the action of currents and fall straight to the bottom.

116. Paleoceanography is

a.	the study of the ocean's past.
b.	analysis of sediment age by tektite content.
c.	the study of ocean color.
d.	analysis of the color of sediments.
e.	none of the above.

117.The oldest ocean floor sediments are about:

a.	160 million years old.
b.	60 million years old.
c.	1 billion years old.
d.	6,000 years old.
e.	600 million years old.

118. The oldest sediments are comparatively young because:

a.	the rocks of the underlying ocean floor react chemically with the lowest sediments, converting them directly into rock.
b.	the ocean floor is recycled through plate tectonics, dragging the oldest sediments into the mantle at subduction zones.
c.	sediments have been falling to the ocean floor only comparatively recently.
d.	the physical and biological processes that make sediments have been active only a comparatively short time.
e.	sediments are consumed by bottom-dwelling marine organisms.

119. San Diego County's geology reflects

a.	a long history of subduction-related magmatism followed by transform faulting.
b.	a long history of seafloor spreading-related magmatism followed by hot spot activity.
c.	a short history of transform faulting followed by some subduction-related magmatism.
d.	a long, quite history of subsidence and sedimentation.
e.	a short history of subduction-related magmatism followed by passive margin sedimentation

120. Theories in geology are developed through a process known as

a.	plate tectonics
b.	uniformitarianism
c.	scientific method
d.	systems approach
e.	none of the above

121. The complete Earth system is composed of

a.	a series of layers that have similar densities, but different compositions
b.	the hydrosphere, lithosphere, mantle, core, biosphere, and atmosphere
c.	a series of layers that have different densities, but similar compositions
d.	igneous, metamorphic and sedimentary rocks
e.	a mantle covered by crust, ocean, and atmosphere

122. Which geologic setting is most suitable for giant strike-slip faults?

a.	transform plate boundary
b.	passive plate margin
c.	oceanic hot spots
d.	subduction zone boundaries
e.	all the above

123 . Water that initiates partial melting in subduction zones comes from

a.	rivers, lakes and streams.
b.	deep within the mantle.
c.	seawater-saturated down-going slab
d.	the atmosphere.
e.	water does not initiate subduction zone melting

124. Main source of water for partial melting in subduction zones.

a.	rainwater.
b.	soil.
c.	groundwater.
d.	rivers and lakes.
e.	dehydration of the slab.

125. The driving force behind plate tectonics and global magmatism is

a.	the heat generated by the burning of fossil fuels
b.	the heat produced by sunlight and retained by carbon dioxide and other gases
c.	internal heat produced by gravitational accretion and radioactivity.
d.	increased gravitational energy as the Earth moves nearer the sun
e.	all of the above

126. Seafloor spreading is associated with which type of tectonic setting?

a.	Divergent plate boundaries
b.	Convergent plate boundaries
c.	Transform plate boundaries
d.	Hot spots
e.	all of the above

127. The primary force causing the tectonic plates to move is

a.	gravity of the sun and moon
b.	deep sea currents.
c.	weight of the glaciers.
d.	core magnetism.
e.	mantle convection.

128. Which of the following statements are true?

a.	ocean basins are relatively young, continents are very old.
b.	ocean basins are very old, continents are relatively young.
c.	ocean basins and continents are about the same age.
d.	we do not know how old ocean basins and continents are.
e.	ocean basins are sunken continents.

129. Most of the rocks in San Diego's backcountry were generated at a

a.	spreading center
b.	hot spot
c.	subduction zone
d.	passive margin

Section IIIA.

Matching: Questions 130 through 136

Directions: Match the tectonic feature (Letter) with its associated term (letter(s))

a.	subduction zone	a+b	active volcanic arc
b.	mid-oceanic ridge	a+c	mantle wedge/zone of dehydration melting
c.	pluton	a+d	oceanic trench
d.	hot spot	a+e	passive margin
e.	Moho discontinuity	b+c	oceanic athenosphere

____ 130. Feature A

____ 131. Feature B

____ 132. Feature C

____ 133. Feature D

____ 134. Feature E

____ 135. Feature F

____ 136. Feature G

Section IIIB.

Matching: Questions 137 through 142

Directions: Match the tectonic feature (Letter) with its associated term (letter(s))

a.	Young oceanic lithosphere
b.	Mid-oceanic rift valley
c.	Zone of decompression melting
d.	Older oceanic lithosphere
e.	Oceanic asthenosphere
a+b	Oceanic trench

____ 137. Feature A

____ 138. Feature B

____ 139. Feature C

____ 140. Feature D

____ 141. Feature E

____ 142. Feature F

Section IIIC.

Matching: Questions 143 through 144

Directions: Match each specified geographic locality (Letter) with its associated tectonic

setting (letter)

a.	transform plate boundary	e.	oceanic-oceanic subduction/ convergent boundary
b.	hot spot	a+b	continent-continent collision/ convergent plate boundary
c.	passive continental margin	a+c	oceanic-continental subduction/ convergent plate boundary
d.	oceanic seafloor spreading center/ divergent plate boundary	a+d	continental rift/divergent plate boundary

____ 143. Locality A

____ 144. Locality B

____ 145. Locality C

____ 146. Locality D

____ 147. Locality E

____ 148. Locality F

____ 149. Locality G

____ 150. Locality X