Introduction to Environmental Geology, 5e (Keller)
Chapter 2 Internal Structure of Earth and Plate Tectonics
2.1 Multiple-Choice Questions
1) What is the principal difference between the inner core and outer core?
A) The inner core consists mainly of iron and nickel, while the outer core consists mainly of
silicate minerals.
B) The inner core consists mainly of silicate minerals, while the outer core consists mainly of
iron and nickel.
C) The inner core is solid while the outer core is liquid.
D) The inner core is liquid while the outer core is solid.
2) The Mohorovicic discontinuity represents
A) the boundary between inner and outer cores
B) the boundary between mantle and crust
C) the boundary between lithosphere and hydrosphere
D) the boundary between outer core and mantle
3) How does the lithosphere differ from the asthenosphere?
A) The lithosphere is stronger than the asthenosphere.
B) The asthenosphere is stronger than the lithosphere.
C) The asthenosphere is part of the core, while the lithosphere is part of the mantle.
D) The asthenosphere is less dense than the lithosphere.
4) Which type of earthquake wave moves fastest?
A) P-wave
B) S-wave
C) L-wave
D) R-wave
5) How do seismologists know the outer core is liquid?
A) P-waves are refracted upon arrival in the outer core
B) S-waves are absorbed upon arrival in the outer core
C) both S-waves and P-waves speed up in the outer core
D) both S-waves and P-waves slow down in the outer core
6) Why was Alfred Wegener’s hypothesis of continental drift not taken seriously by most
geologists?
A) his evidence for former joining of the continents was faulty
B) because it was and is known that continents do not move
C) his mechanism for movement of the continents was faulty
D) he was not a well-respected scientist
7) How did seafloor spreading revive Alfred Wegener’s ideas about continental drift?
A) Sea floor spreading relied on new fossil evidence documenting the former joining of the
continents.
B) Sea floor spreading provided an explanation for the consumption of oceanic crust at plate
boundaries.
C) The topography of the ocean floor demonstrated that mountain ranges on either side of the
Atlantic Ocean were formerly joined.
D) Sea floor spreading prevented a viable mechanism for moving the continents.
8) At convergent plate boundaries
A) the plate of higher density subducts into the mantle
B) the plate of lower density subducts into the mantle
C) new oceanic crust is created
D) magnetic stripes are generated in oceanic rocks
9) Transform plate boundaries are marked by
A) volcanic island arcs
B) consumption of oceanic crust
C) creation of oceanic crust
D) two plates sliding relative to one another
10) How do magnetic stripes on the ocean floor serve as evidence for seafloor spreading?
A) Their symmetry on either side of the mid-ocean ridge shows that new crust is created, then
split.
B) Their patterns show that the Earth’s magnetic field reverses every few hundred years, on
average.
C) They show that island arc volcanism creates new oceanic crust at the mid-ocean ridges.
D) Their symmetry on either side of mid-ocean ridges shows that transform boundaries are
sliding boundaries.
11) Hot spots are recorded by
A) extensive earthquake hazards
B) mantle rock exposed at the Earth’s surface
C) rock from the outer mantle included in volcanic rocks
D) a sequence of volcanic centers younging toward the hot spot
12) The process of isostasy is responsible for
A) moving plates apart at a divergent margin
B) creating volcanoes at a hot spot
C) causing rock uplift in mountain ranges in response to erosion
D) causing compressive stresses at convergent boundaries
13) Tectonic plates move about as fast as
A) a car moves on a city street
B) fingernails grow
C) a swallow flies
D) a tortoise walks
14) When did the supercontinent Pangaea start breaking apart?
A) 4.6 billion years ago
B) 560 million years ago
C) 180 million years ago
D) 65 million years ago
15) What driving force of plate movement is likely dominant?
A) ridge push
B) slab pull
C) mountain rise
D) valley fall
1) The rocks of the core are more dense than the rocks of the mantle.
2) The asthenosphere is stronger than the lithosphere.
3) S-waves accelerate as they enter the outer core.
4) Alfred Wegener proposed the idea of sea floor spreading.
5) Crust is consumed at transform boundaries.
6) A submarine trench is associated with a convergent boundary.
7) The Earth’s magnetic field reverses in a regular pattern every few hundred thousand years.
8) The concept of seafloor spreading was supported by magnetic polarity stripes on the ocean
floor.
9) The Hawaiian Islands are a volcanic arc atop an oceanic subduction zone.
10) Plate tectonic processes can affect climate.
11) New oceanic lithosphere is generated at mid-ocean ridges.
12) Transform boundaries do not generate earthquakes.
13) Deep (>200 km) earthquakes can only be found at a convergent boundary.
14) Only a few transform boundaries (<10) mark the Earth’s tectonic plates.
1) The rocks of the core consist mostly of ________.
2) The ________ separates the mantle and the crust.
3) A change in the direction of wave travel at the core-mantle boundary is called ________.
4) ________-waves pass through the outer core.
5) Convergence of plates can cause ________ forces that build mountain ranges.
6) ________ can cause uplift in a mountain range through isostatic compensation.
7) A(n) ________ is a location where three plates border one another.
8) At the Curie point, iron-bearing minerals orient themselves parallel to the ________.
9) The volcano called ________ is the youngest of the Hawaiian volcanoes.
10) The supercontinent Pangaea consisted of Laurasia and ________.
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11) Yellowstone National Park lies atop a(n) ________.
12) The Cascade Mountains are part of a(n) ________ convergent boundary.
13) The San Andreas Fault is a(n) ________ boundary.