Blakeley Jones
GEOL 1104
Review 6 – Earth’s Interior and Plate Tectonics
Chapter 12 Earth's Interior
Earth: An Introduction to Physical Geology, 9e (Tarbuck/Lutgens)
12.1 Multiple-Choice Questions
1) The P-wave shadow zone is largely the result of ________.
A. reflection of P waves from the inner core-outer core boundary
B. lower P-wave velocities in the mantle than in the crust
C. refraction of P waves crossing the mantle-outer core boundary
D. reflection of P waves at the boundary between the inner and outer cores
For the following questions (6-12), match the layers of the Earth with the appropriate description.
A. inner core
B. mantle
C. crust
D. outer core
6) ____C____ upper part of the lithosphere includes this layer
7) ____A____ very dense, solidified, iron-rich alloy
9) ____D___ transmits P waves but not S waves
10) ___B____ the top of this layer is marked by the Mohorovicic discontinuity
11) ___B_____ includes the asthenosphere
12) ___C_____ includes large percentages of feldspars and quartz
13) Which of the following best characterizes how the diameter of Earth's core and the nature of the outer core were
discovered?
A. Crystalline iron was found in lavas erupted from the deepest known hot spots.
B. By analysis of the P-wave and S-wave shadow zones.
C. Because P-wave speeds are higher in the outer core than in the lower mantle.
D. By using the ratio of iron meteorites to stony meteorites to deduce the relative diameters of the core and
mantle.
15) The fact that ________ is good evidence for a solidified, inner core.
A. S waves do not pass directly through the core
B. P waves are faster in the inner core than in the outer core
C. S waves are slower in the inner core than in the outer core
D. S waves are focused at the center of the P-wave shadow zone
17) The ________ of the Earth does not transmit S waves.
A. outer mantle
B. inner crust
C. outer core
D. deep mantle
19) The ________ of the Earth has the smallest volume.
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A.
B.
C.
D.
crust
outer core
mantle
inner core
23) ________ is probably closest in chemical composition to the upper mantle.
A. Granite
B. Shale
C. Andesite
D. Peridotite
24) ________ are closest to the average chemical composition of the oceanic crust.
A. Basalt and gabbro
B. Granite and limestone
C. Andesite and granite
D. Rhyolite and diorite
For questions 28-31, match the phrases with the appropriate descriptions.
A. the "D" layer
B. the low-velocity zone
C. the mesosphere
D. the 660-km-depth discontinuity
28) ____B____ zone of incipient partial melting in the upper mantle
29) ____C___ most of the lower mantle; more rigid than the asthenosphere
30) ____D____ caused by the transition from the spinel to the perovskite mineral structure
31) ____A____ implicated in the upward flow of warmed mantle from near the core-mantle boundary
12.3 True/False Questions
3) Continental crust has an average chemical composition much like the igneous rock andesite; the oceanic crust is
basaltic in composition. FALSE
4) T or F: On the basis of seismic evidence, the outer core is believed to be liquid.
5) T or F: The crust and mantle are solids; the inner core is thought to be solid.
6) T or F: The mantle is composed mainly of iron with small amounts of magnesium silicate minerals.
7) T or F: The S-wave shadow zone exists because S waves cannot pass through the outer core.
8) T or F: Continental crust is generally thicker than oceanic crust.
13) T or F: Stony and iron meteorites are thought to provide samples of the materials from which Earth originally
formed.
Chapter 2 Plate Tectonics: A Scientific Revolution Unfolds
Earth: An Introduction to Physical Geology, 9e (Tarbuck/Lutgens)
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2.1 Multiple-Choice Questions
2) In the early part of the 20th century, ________ argued forcefully for continental drift.
A. Karl Wagner
B. Peter Rommel
C. Alfred Wegener
D. Bill Kohl
3) The former, late Paleozoic super continent is known as ________.
A. Pandomonia
B. Pancakea
C. Pangaea
D. Panatopia
6) The ________ is an example of an active, continent-continent collision?
A. Arabian Peninsula slamming into North Africa under the Red Sea
B. westward movement of the South American plate over the Nazca plate
C. northern movement of Baja California and a sliver of western California toward the Hawaiian Islands
D. northward movement of India into Eurasia
7) Pull-apart, rift zones are generally associated with a ________ plate boundary.
A. transform
B. divergent
C. convergent
D. all plate boundaries
8) The temperature below which magnetic material can retain a permanent magnetization is called the ________.
A. Darcy temperature
B. Vine temperature
C. Bullard point
D. Curie point
9) Deep-focus earthquakes, those between 300 and 700 kilometers below the surface, occur only in association with
________.
A. subduction zones
B. mid-ocean ridges
C. transform faults
D. hot spots
10) A very long-lived magma source located deep in the mantle is called a ________.
A. magma welt
B. basalt spout
C. melt well
D. hot spot
11) Linear, magnetic patterns associated with mid-ocean ridges are configured as ________.
A. concentric circles about a rising plume of hot, mantle rocks and magma
B. reversed magnetizations along the rift valleys and normal magnetizations along the ridge
C. normal and reversed magnetized strips roughly parallel to the ridge
D. normal and reversed magnetized strips roughly perpendicular to the ridge axis
15) The continental drift hypothesis was rejected primarily because Alfred Wegener could not ________.
a. find geologic similarities on different continents
b. disprove competing theories that were more accepted by scientists
c. identify a mechanism capable of moving continents
d. all of the above
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16) All of the following are evidence supporting the theory of plate tectonics except for ________.
a. changes in the Moon's orbit due to shifting plates
b. ocean floor drilling
c. hot spots
d. measurements of plate motions
19) Which one of the following most accurately describes the volcanoes of the Hawaiian Islands?
a. stratovolcanoes associated with subduction and a convergent plate boundary
b. shield volcanoes fed by a long-lived hot spot below the Pacific lithospheric plate
c. shield volcanoes associated with a mid-Pacific ridge and spreading center
d. stratovolcanoes associated with a mid-Pacific transform fault
20) Which of the following statements apply to the asthenosphere, but not the lithosphere?
a. zone in the upper mantle that deforms by plastic flowage
b. cool, rigid layer of crust and upper mantle that forms the tectonic plates
c. deforms mainly by brittle fracturing and faulting
d. partial melting of rising granitic plumes produces huge volumes of basaltic magma
22) New oceanic crust and lithosphere are formed at ________.
a. divergent boundaries by submarine eruptions and intrusions of rhyolitic magma
b. convergent boundaries by submarine eruptions and intrusions of rhyolitic magma
c. divergent boundaries by submarine eruptions and intrusions of basaltic magma
d. convergent boundaries by submarine eruptions and intrusions of basaltic magma
23) Cooler, older, oceanic lithosphere sink into the mantle at ________.
a. subduction zones along convergent plate boundaries
b. transform fault zones along divergent plate boundaries
c. rift zones along mid-ocean ridges
d. sites of long-lived, hot spot volcanism in the ocean basins
24) Deep ocean trenches are surficial evidence for ________.
a. rifting beneath a continental plate and the beginning of continental drift
b. sinking of oceanic lithosphere into the mantle at a subduction zone
c. rising of hot asthenosphere from deep in the mantle
d. transform faulting between an oceanic plate and a continental plate
25) A transform plate boundary is characterized by ________.
a. stratovolcanoes on the edge of a plate and shield volcanoes on the adjacent plate
b. two, converging, oceanic plates meeting head-on and piling up into a mid-ocean ridge
c. a divergent boundary where the continental plate changes to an oceanic plate
d. a deep, vertical fault along which two plates slide past one another in opposite directions
26) ________ plate boundaries have the largest magnitude earthquakes.
a. Divergent and transform
b. Transform and convergent
c. Divergent and convergent
d. All plate boundaries have large magnitude earthquakes.
28) The modern-day Red Sea is explained by plate tectonics theory because it is ________.
a. a tiny remnant of a once immense ocean that was closed as Africa moved Asia
b. the site of a transform fault along which Arabia is moving away from Africa
c. a rift zone that may eventually open into a major ocean if Arabia and Africa continue to separate
d. a rare example of a two-continent subduction zone where the African continental plate is sinking under the
Arabian continental plate
29) Mount St. Helens and the other Cascade volcanoes are ________.
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a.
b.
c.
d.
young, active stratovolcanoes built on a continental margin above a sinking slab of oceanic
lithosphere
a row of young, active, shield volcanoes built as western North America moved over a hot spot deep in the
mantle
old, deeply eroded stratovolcanoes built before the Pacific Ocean existed
old, deeply eroded, basaltic shield volcanoes built when western North America was over the present-day
site of the Hawaiian hot spot
34) ________ most effectively outline the edges of the lithospheric plates.
a. Lines of active stratovolcanoes
b. Margins of the continental shelves
c. The locations of deep mantle hot spots
d. Lines of earthquake epicenters
36) Deep-oceanic trenches are most abundant around the rim of the ________ ocean basin.
a. Atlantic
b. Indian
c. Arctic
d. Pacific
2.3 True/False Questions
1) T or F: The oldest rocks on the seafloor are much younger than the oldest rocks on the continents.
2) T or F: Earth's radius and surface area are slowly increasing to accommodate the new oceanic crust being formed
at mid-oceanic ridges.
4) T or F: The oldest rocks of the oceanic crust are found in deep ocean trenches far away from active, mid-ocean
ridges.
5) T or F: As the South Atlantic basin widens by seafloor spreading, Africa and South America are moving closer
together.
6) T or F: In general, rocks of the continental crust are less dense than rocks of the oceanic crust.
8) T or F: During various times in the geologic past, the polarity of Earth's magnetic field has been reversed.
9) T or F: The rate of seafloor spreading is, on the average, about one meter per year.
10) T or F: Wegener's continental drift hypothesis was weakened because a viable mechanism for moving the
continents was lacking.
14) T or F: Iceland is a good example of an island arc, formed from an oceanic-oceanic plate collision.
Chapter 13 Divergent Boundaries: Origin and Evolution of the Ocean Floor
Earth: An Introduction to Physical Geology, 9e (Tarbuck/Lutgens)
13.1 Multiple-Choice Questions
16) Oceanic ridges are elevated compared to the surrounding ocean floor because ________.
a. newly formed lithosphere is hotter and therefore less dense than the surrounding rocks
b. the older, colder lithosphere is less dense and tends to rise
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c.
d.
the mantle is pushing up the lithosphere along the ridge
of the shield volcanoes that develop due to seafloor spreading
20) ________ develop where oceanic lithosphere bends downward and sinks into the mantle.
a. Submarine canyons
b. Abyssal seamounts
c. Deep ocean trenches
d. Rift valleys on mid-ocean ridges
21) Spreading rates of ________ are common along the Mid-Atlantic and the Mid-Indian ridges.
a. 1 to 5 meters per year
b. 1 to 5 centimeters per year
c. 1 to 5 kilometers per year
d. 1 to 5 millimeters per year
13.3 True/False Questions
4) T or F: The Atlantic and Pacific basins have oceanic ridges; the Indian Ocean has no oceanic ridge.
5) T or F: Oceanic ridges are lower then the surrounding ocean floor due to the warm, less dense oceanic crust
found along the ridges.
6) T or F: Deep-ocean trenches mark the sites where lithospheric plates are subducting back into the mantle.
Chapter 14 Convergent Boundaries: Origin of Mountains
Earth: An Introduction to Physical Geology, 9e (Tarbuck/Lutgens)
14.1 Multiple-Choice Questions
5) A(n) ________ is a thick accumulation of sediments and small, tectonic blocks formed of material scraped off a
descending, lithospheric plate.
a. mass movement complex
b. continental shelf, terrain complex
c. accretionary-wedge complex
d. subterranean-accumulation complex
21) Since the early Mesozoic, the ________ has been passive tectonically.
a. western margin of North America
b. western margin of South America
c. southern margin of Eurasia
d. eastern margin in the United States
22) Accretionary wedges are formed ________.
a. at the edge of the overriding plate facing a subduction zone
b. at the base of a passive continental margin
c. on the oceanic plate side of a transform fault
d. around oceanic plate volcanoes fed by long-lived hot spots in the mantle
25) Subduction zones include all of the following except for ________.
a. deep ocean trenches
b. forearc basins
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c.
d.
suture zones
volcanic arcs
26) Backarc regions are characterized by ________.
a. compression
b. shearing
c. uplift
d. extension
27) Volcanism along a continental arc is dominated by the eruption of ________.
a. basaltic lava flows
b. andesitic lavas and pyroclastic materials
c. rhyolitic pyroclastic materials and lavas
d. all of the above
14.3 True/False Questions
2) T or F: The Himalayan Mountains and Tibetan Plateau are still rising today as Eurasia slides beneath the Indian
subcontinent.
7) T or F: Accretionary wedges develop along subduction zones where sediments and other rocks are scraped off a
descending plate and piled against the leading edge of the overriding plate.
8) T or F: Volcanic island arcs and granitic, batholithic zones develop along convergent margins on the overriding
plate above an oceanic plate sinking into the mantle.
11) T or F: Passive, trailing, continental margins typically exhibit normal faults that were active when the original,
single continent was rifted.
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