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Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Early results of the Deep Sea Drilling Project clearly justified the conclusion that ________.
the ocean basins are relatively young; most ocean basin rocks and sediments are Cretaceous
or younger in age
the youngest sediments were deposited directly on the oldest seafloor basalts
Proterozoic rocks are found only as seamounts in the deepest parts of the ocean basins
the oceans have not always contained most of Earth’s water
A transform plate boundary is characterized by ________.
two converging oceanic plates meeting head–on and piling up into a mid–ocean ridge
a deep, vertical fault along which two plates slide past one another in opposite directions
stratovolcanoes on the edge of a plate and shield volcanoes on the adjacent plate
a divergent boundary where the continental plate changes to an oceanic plate
The volcanoes and deep valleys of east Africa are related to a ________.
continental rift along which parts of the African continent are beginning to slowly separate
continental collision zone between Africa and the Zagros Mountains along the southern
margin of Eurasia
fault allowing Arabia to slip westward past east Africa and penetrate into Turkey
transform fault aligned with the Red Sea carrying the Arabian and African blocks in opposite
directions
The temperature below which magnetic material can retain a permanent magnetization is called
the ________.
The modern–day Red Sea is explained by plate tectonics theory because it is ________.
a rift zone that may eventually open into a major ocean if Arabia and Africa continue to
separate
a rare example of a two–continent subduction zone where the African continental plate is
sinking under the Arabian continental plate
the site of a transform fault along which Arabia is moving away from Africa
a tiny remnant of a once immense ocean that was closed as Africa moved Asia
The ________ is(are) a logical evolutionary analog of the African Rift Valleys ten million years from
now.
The ________ is an example of an active, continent–continent collision.
northern movement of Baja California and a sliver of western California toward the Hawaiian
Islands
northward movement of India into Eurasia
westward movement of the South American plate over the Nazca plate
Arabian Peninsula slamming into North Africa under the Red Sea
The continental drift hypothesis was rejected primarily because Alfred Wegener could not
________.
disprove competing theories that were more accepted by scientists
find geologic similarities on different continents
identify a mechanism capable of moving continents
A
A typical rate of seafloor spreading in the Atlantic Ocean is ________.
Which one of the following most accurately describes the volcanoes of the Hawaiian Islands?
stratovolcanoes associated with a mid–Pacific transform fault
shield volcanoes associated with a mid–Pacific ridge and spreading center
stratovolcanoes associated with subduction and a convergent plate boundary
shield volcanoes fed by a long–lived hot spot below the Pacific lithospheric plate
Which of the following energy sources is thought to drive the lateral motions of Earth’s lithospheric
plates?
electrical and magnetic fields localized in the inner core
gravitational attractive forces of the Sun and Moon
export of heat from deep in the mantle to the top of the asthenosphere
swirling movements of the molten iron particles in the outer core
________ was never proposed as evidence supporting the existence of Pangaea.
Islands of Precambrian rocks along the Mid–Atlantic Ridge
Geometrical fit between South America and Africa
Late Paleozoic glacial features
Similar fossils on different continents
Deep–oceanic trenches are most abundant around the rim of the ________ ocean basin.
Which one of the following is an important fundamental assumption underlying the plate tectonic
theory?
Earth‘s ocean basins are very old and stable features.
Earth‘s magnetic field originates in the outer core.
Earth’s diameter has been essentially constant over time.
Radioactive decay slows down at the extreme pressures of the inner core.
Which of the following statements apply to the asthenosphere, but not the lithosphere?
cool, rigid layer of crust and upper mantle that forms the tectonic plates
deforms mainly by brittle fracturing and faulting
partial melting of rising granitic plumes produces huge volumes of basaltic magma
zone in the upper mantle that deforms by plastic flowage
In the early part of the twentieth century, ________ argued forcefully for continental drift.
The Aleutian Islands occur at a ________.
transform boundary where North America has moved towards Alaska
convergent, continental margin with uplifted fault blocks, much like those of the Basin and
Range Province
convergent boundary on a volcanic arc above a northward–subducting Pacific plate
divergent boundary where shield volcanoes are forming
The late Paleozoic supercontinent is known as ________.
Cooler, older, oceanic lithosphere sinks into the mantle at ________.
subduction zones along convergent plate boundaries
transform fault zones along divergent plate boundaries
sites of long–lived, hot spot volcanism in the ocean basins
rift zones along mid–ocean ridges
Pull–apart rift zones are generally associated with a ________ plate boundary.
A very long–lived magma source located deep in the mantle is called a ________.
New oceanic crust and lithosphere are formed at ________.
convergent boundaries by submarine eruptions and intrusions of rhyolitic magma
divergent boundaries by submarine eruptions and intrusions of rhyolitic magma
convergent boundaries by submarine eruptions and intrusions of basaltic magma
divergent boundaries by submarine eruptions and intrusions of basaltic magma
________ was an ancient reptile that lived in South America and Africa during the late Paleozoic.
Today, ________ is in about the same geographic position as during late Paleozoic time.
Linear, magnetic patterns associated with mid–ocean ridges are configured as ________.
normal and reversed magnetized strips roughly parallel to the ridge
concentric circles about a rising plume of hot mantle rocks and magma
normal and reversed magnetized strips roughly perpendicular to the ridge axis
reversed magnetizations along the rift valleys and normal magnetizations along the ridge
All of the following are evidence supporting the theory of plate tectonics EXCEPT for ________.
changes in the Moon’s orbit due to shifting plates
________ first related the symmetrical magnetic patterns in seafloor basalts to seafloor spreading at
a mid–ocean ridge.
Deep ocean trenches are surficial evidence for ________.
rising of hot asthenosphere from deep in the mantle
transform faulting between an oceanic plate and a continental plate
rifting beneath a continental plate and the beginning of continental drift
sinking of oceanic lithosphere into the mantle at a subduction zone
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
During the first two decades of the twentieth century, ________ was a vigorous proponent
of continental drift.
The San Andreas fault in California is a good example of a(n) ________ plate boundary.
A(n) ________ is a long–lived, stationary magma source deep in the mantle, well below the
base of the lithosphere.
Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the
majority of words/phrases. Choose the option that does not fit the pattern.
a. fossil evidence b. fit of the continents c. paleomagnetism d.
paleoclimates
The ________ today marks the location of the rift along which Africa separated from South
America.
Japan and the Aleutian Islands have formed from a(n) ________ to ________ convergent
boundary.
Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the
majority of words/phrases. Choose the option that does not fit the pattern.
a. slab pull b. mantle drag c. ridge push d. slab suction
________, in the north Atlantic Ocean, is a volcanic island formed over a hot spot on a
divergent plate boundary.
Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the
majority of words/phrases. Choose the option that does not fit the pattern.
a. oceanic ridge b. seafloor spreading c. arc volcanoes d. divergent
Rifting and normal faulting are characteristic of a(n) ________ plate boundary.
Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the
majority of words/phrases. Choose the option that does not fit the pattern.
a. Hawaii b. island arc c. volcanic arc d. subduction
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
During various times in the geologic past, the polarity of Earth‘s magnetic field has been reversed.
Iceland is a good example of an island arc, formed from an oceanic–oceanic plate collision.
The oldest rocks of the oceanic crust are found in deep ocean trenches far away from active,
mid–ocean ridges.
Seafloor spreading rates can be estimated if the geologic ages of the magnetic field reversals are
independently known.
During the geologic past, the magnetic field poles have generally been very close to Earth’s
rotational poles.
Earth’s radius and surface area are slowly increasing to accommodate the new oceanic crust being
formed at mid–ocean ridges.
Wegener’s continental drift hypothesis was weakened because a viable mechanism for moving the
continents was lacking.
In general, rocks of the continental crust are less dense than rocks of the oceanic crust.
As the South Atlantic basin widens by seafloor spreading, Africa and South America are moving
closer together.
The Himalayan Mountains are the tectonic product of a collision between India and Eurasia that
began in Eocene time and still continues.
An extensive, late Paleozoic glaciation affected southern India, southern Africa and southeastern
South America.
The volcanoes of Hawaii are localized above a deep mantle hot spot; they are not part of the East
Pacific oceanic ridge.
Hawaii is the oldest island of the Hawaiian Island chain.
The oldest rocks on the seafloor are much younger than the oldest rocks on the continents.
The rate of seafloor spreading is, on the average, about one meter per year.
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the plate boundary with the appropriate phrase.
plates are moving apart from one
another
plates are sliding past one another
horizontally
where subduction zones occur
this boundary is normally devoid of
volcanism
the west coast of South America
where lithosphere is sinking into the
mantle
characterized by basaltic volcanism
and seafloor spreading
characterized by arcs of
stratovolcanoes and deep–ocean
trenches
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
Critical thinking and discussion questions. Use complete sentences, correct spelling, and the information presented in
chapter 2 to answer the questions below.
Fill in the blanks with the correct name of the feature that is labeled.
If you could time travel back to the 1920s and meet Alfred Wegener, who was the original proponent of the
continental drift hypothesis, what could you tell him about our modern idea of plate tectonics? What would you
tell him regarding the structure of the Earth’s interior, what evidence exists for plate tectonics, what is the
relationship between volcanoes and earthquakes to plate tectonics (specifics), and what are some (if any) of the
problems we still have in explaining certain features of plate tectonics?
Although Alfred Wegener presented compelling evidence for his continental drift hypothesis (despite lacking a
mechanism), why was the true nature of plate boundaries not determined until the 1960s?
Describe exactly what type of plate boundary is illustrated below and explain your answer.
In the diagram below, match the letter of each illustration to the correct type of plate boundary.
A) convergent B) transform C) divergent