Chapter 17 Unit 13 Earth's Interior
13.The crust and upper mantle form the ____. A. lithosphere B.athenosphere C.core D.outer core E.Moho discontinuity
A
A positive magnetic anomaly could indicate A) a body of magnetic ore B) the magnetic field strength is higher than the regional average C) an intrusion of gabbro D) the presence of a granitic basement high E) All of these choices are correct.
) All of these choices are correct.
11.The bending of seismic waves as they pass from one material to another is called seismic____. A. refraction B. reflection C. deflection D. attenuation E. waves don't bend when they pass through different materials.
A
14._____ is the return of some of the energy of a seismic wave to the Earth's surface after it bounces off a rock boundary. A.Seismic reflection B.Seismic refraction C.Seismic attenuation D.Seismic adjustment E.Seismic shadow zone
A
18. The rise of the crust after removal of ice is called ____. A. crustal rebound B.tectonic uplift C.upheaval D.subduction E.dynamic adjustment
A
2.Recently, geologists have been analyzing ____ generated by tidal friction, ocean waves, and storms to gain an even more detailed image of the crust and upper mantle. A. energy waves B. light sources C. water movement D. evaporation E. ocean currents
A
20.The P-wave shadow zone can be explained by the refraction of P-waves at the ___. A. core-mantle boundary B. asthenosphere-lithosphere boundary C. Moho D. inner core-outer core boundary E. 670 km depth limit
A
24.At a pressure equivalent to a depth of 670 km the mineral olivine collapses to form ____. A. perovskite B. quartz C. mica D. calcite E. zircon
A
27._____ predicts that the higher a mountain range extends above sea level the deeper it extends into the mantle. A. Isostatic adjustment B. Crustal rebound C. Mantle convection D. Mohorovicic discontinuity E. Subducting oceanic lithosphere
A
28.Oceanic crust is _____ continental crust. A. thinner than B.thicker than C.the same thickness as D.the same composition as E.the same seismic velocity as
A
32.The rock record for tens of millions of years indicates that the Earth's magnetic field____. A. reverses polarity about every 500,000 years B. is constant in strength and polarity C. did not come into existence until about 1 million years ago D. is a monopole magnet E. has steadily weakened and will be gone in another 10 million years
A
33.The ____ is a low velocity seismic zone. A. asthenosphere B.lower crust C.core D.outer core E.Mohorovicic discontinuity
A
36.Because _____ can be accurately calculated, the size and shape of the core can be determined. A. P-wave paths B. surface wave paths C. gravitational anomalies D. heat flow conditions
A
12.The boundary that separates the crust from the mantle is the ____. A. mantle discontinuity B. Mohorovicic discontinuity C. lithospheric discontinuity D. athenospheric discontinuity E. shadow zone
B
15.Seismic P-waves _____ through continental crust relative to oceanic crust. A. travel faster B. travel slower C. stay the same velocity D. are refracted E. are reflected
B
21.Iron-nickel meteorites are an important source of information regarding the composition of Earth's ______. A. oceanic crust B. core C. mantle D. asthenosphere E. continental crust
B
34.Heat flow ______ the crest of the mid-oceanic ridges. A. increases away from B. decreases away from C. does not change relative to D. is unknown on E. is the highest on Earth on
B
38._______ is a balance or equilibrium of adjacent blocks of brittle crust floating on the upper mantle. A. Density adjustment B. Isostasy C. Gravity adjustment D. Inertial adjustment E. Thermohaline flow
B
4._____ is a circulation pattern in which low-density material rises and high-density material sinks. A. Conduction B. Convection C. Density flow D. Refraction E. Reflection
B
40.The magnetic poles are displaced about ______ degrees from the geographic poles. A. 5½ B. 11½ C.16½ D.30½ E.45½
B
6.A region of magnetic force, called the ______ surround Earth. A. magnetic force B. magnetic field C. magma field D. magnetic poles E. magnetism
B
When discussing the movement of seismic body waves through the Earth, what is a shadow zone? A) A place on the surface where a certain type of wave is not received B) A place on the surface where a certain type of wave received is weaker than usual C) A place on the surface where a certain type of wave received is stronger than usual D) A place on the surface where a certain type of wave received is faster than usual
B) A place on the surface where a certain type of wave received is weaker than usual
1._____ is the branch of geology that applies physical laws and principles to study Earth. A. Earthquakology B. Physicalogy C. Geophysics D. Palentology E. Environmental geology
C
16.The upper mantle consists of _______. A.granite B.basalt C. ultramafic rocks D.metamorphic rocks E.sedimentary rocks
C
19.Continental crust is ___ relative to oceanic crust. A. the same thickness B. thinner C. thicker D. hotter E. of unknown relation
C
22.The ____ is the transition zone at the core-mantle boundary. A.Moho B.asthenosphere C. D layer D.perovskite zone E.unnamed surface
C
26.Hot mantle rock rising slowly by convection under parts of the ocean explains ____. A.mid-oceanic ridges B.underwater volcanoes C. the unexpectedly high heat flow under the oceans D.the thickness of the continents E.the location of earthquakes
C
29. A cavity or body of low-density material causes a _____ pull on a gravity meter relative to average crust. A.stronger B.greater than the surrounding rock C.weaker D.rapidly increasing E.Gravity can't be measured.
C
35.The gradual loss of heat through the Earth's surface is called ___. A. thermal decay B. cooling trend C. heat flow D. thinning of the heat E. convection
C
7.A gravity reading lower than the normal regional gravity indicates that a region is ____. A. actively being uplifted B. under a high magnetic field C. being held down D. a good prospect for an ore deposit E. undergoing elastic rebound
C
9.A deviation from average reading is called a(n) ____. A. deviant B. negative C. anomaly D. above or below average E. positive
C
17. What is the asthenosphere? A.It is the surface that separates the crust from the mantle. B.It is the zone that separates the continental crust from the oceanic crust. C.It is in the surface that separates the inner and outer core. D. It is the zone of weakness in the mantle on which the lithosphere moves. E. It is the same as the Gutenberg Discontinuity.
D
23.___ indicates that the core of the Earth is a liquid. A.Density calculations B.Studies of meteorites C.The P-wave shadow zone D. The S-wave shadow zone E. The Earth's heat flow
D
3.Detailed images provided by _____ suggest that the mantle is heterogeneous, probably due to variations in temperature, composition, and density. A. p-waves B. shadow zone C. deep drill holes D. seismic reflection E. seismic tomography
D
30.A gravity meter registers _____ over ore bodies. A. zero gravity readings B. constant gravity C. decreased gravity D. increased gravity E. You can't explore for metallic deposits with a gravity meter.
D
37.One widely accepted hypothesis is that the Earth's magnetic field is created by electric currents within the ______. A. asthenosphere B. crust C. lower mantle D. liquid outer core E. sun
D
8.The study of ancient magnetic fields is called ____. A.paleontology B.old magnetism C.Curie point D. paleomagnetism E. magnetic polarities
D
10.High _____ is usually an indication of a magma body or still-cooling pluton near the surface. A. geothermal gradient B. heat loss C. convection D. conduction E. heat flow
E
25.The boundary between the core and the mantle is marked by great changes in ____. A.seismic velocity B.density C.temperature D.Both seismic velocity and density are correct. E. Seismic velocity, density, and temperature are all correct.
E
31.As lava cools below the _____ point, a record of the Earth's magnetic field is permanently trapped in the rock. A. freezing B. burning C. boiling D. melting E. Curie
E
39.The average temperature increase in the shallow crust (the geothermal gradient) is about______ degrees C per kilometer. A. 2 B. 5 C. 10 D. 15 E. 25
E
5.A ____ is a tool used to study the gravitational attraction between Earth and a mass within the instrument. A. seismic reflection study B. sonograph C. gravitation recorder D. seismograph E. gravity meter
E
Which of the following is the only description that does not describe magnetic reversals? A) They are recorded in the ocean crust. B) They are recorded in continental lava flows. C) We are unsure why they occur. D) They occur roughly every 500,000 to 700,000 years. E) They occur instantaneously.
E) They occur instantaneously.
Felsic and mafic are terms used by some geologists to describe A) composition of continental and oceanic crust B) behavior of earthquake waves C) regions in the mantle
A) composition of continental and oceanic crust
A positive gravity anomaly indicates that A) tectonic forces are holding a region up out of isostatic equilibrium B) the land is sinking C) local mass deficiencies exist in the crust D) All of these choices are correct.
A) tectonic forces are holding a region up out of isostatic equilibrium
66) The discovery of geomagnetic polar reversals and their patterns was strong evidence that supported ________. A) the theory of plate tectonics B) continental drift C) a liquid inner core D) isostatic rebound
A) the theory of plate tectonics
We study the mantle ________. Choose the phrase that does not apply. A) using rocks that have been naturally brought to the surface B) by drilling directly into it C) using seismic waves D) using numeric models E) using geophysics
B) by drilling directly into it
The principle of continents being in a buoyant equilibrium is called A) subsidence B) isostasy C) convection D) rebound
B) isostasy
Which of the following is not an example of the effects of isostasy? A) deep mountain roots B) magnetic reversals C) the postglacial rise of northeastern North America D) mountain ranges at subduction zones
B) magnetic reversals
The lithosphere is thicker beneath ________. A) the oceans compared to the continents B) the continents compared to the oceans C) the Northern Hemisphere compared to the Southern Hemisphere D) the Southern Hemisphere compared to the Northern Hemisphere
B) the continents compared to the oceans
What would you expect the geothermal gradient to be under Yellowstone as compared to the eastern United States? A) The gradient would be the same in both places. B) The gradient would not exist in the eastern United States. C) The gradient would be higher under Yellowstone. D) The gradient would be lower under Yellowstone.
C) The gradient would be higher under Yellowstone
Isostasy explains the relationship between elevation and crustal thickness. What is an alternative explanation for a region having a high elevation? A) The rocks there are very dense. B) Pools of water exist beneath the rocks. C) The region is buoyed by higher temperatures. D) The rocks there are extremely porous.
C) The region is buoyed by higher temperatures.
Earth's magnetic poles appear to ________. A) never move B) switch positions every 100 years C) slowly move around the geographic poles over decades D) quickly move over large distances yearly
C) slowly move around the geographic poles over decades
The S-wave shadow zone is evidence that A) the core is made of iron and nickel B) the inner core is solid C) the outer core is fluid D) the mantle behaves as ductile material
C) the outer core is fluid
71) The core is probably composed mainly of A) silicon B) sulfur C) oxygen D) iron
D) iron
