Deck 3: Drifting Continents and Spreading Seas

Question 1

Late Paleozoic glacial deposits are NOT found in which of the following places?

A)India
B)southern Africa
C)North America
D)South America

Answer 1

C

Question 2

In Wegener's evidence for continental drift,continents were proposed to fit together,such as the east coast of South America with the ________.

A)west coast of Europe
B)east coast of Africa
C)west coast of Greenland
D)lower west coast of Africa

Answer 2

D

Question 3

Wegener's proposal that the continents had once fit together as a single supercontinent was rejected by geologists at the time because ________.

A)Wegener could not provide a driving force
B)the continents did not fit together tightly enough
C)the fossil evidence was inconclusive
D)the distribution of climatic belts did not make sense in that configuration

Answer 3

A

Question 4

Limestone reefs and salt deposits are important rocks in the reconstruction of Earth history because they ________.

A)can be used to infer the ancient climate of the Earth;they are deposited in environments that are restricted to warm climate
B)automatically provide age information;all such deposits occurred between 200 and 400 million years ago
C)are deposited in warm climates today,but there is good reason to think that they were deposited in cold climates millions of years ago
D)pinpoint the locations of old subduction zones

Question 5

In the geologic past,the polarity of the Earth's magnetic field is ________.

A)unknown,but it is assumed to have been identical to today's
B)known to have stayed constant through geologic time,as shown by remnant magnetization of iron-rich minerals in rocks
C)known to have experienced numerous reversals,as shown by remnant magnetization of iron-rich minerals in rocks
D)known to have stayed constant through time,based on theoretical calculations

Question 6

If we mentally align the continents to fit Wegener's concept of Pangaea,evidence of Late Paleozoic glacial deposits ________.

A)is more difficult to explain than in the modern continental configuration
B)is much more readily explained than in the modern continental configuration
C)makes very little sense in either the Pangaea configuration or the modern configuration
D)is unchanged from the modern continental configuration

Question 7

Wegener's idea of continental drift was rejected by American geologists because ________.

A)his English was too poor to be understood by them
B)he could not conceive of a valid mechanism that would cause continents to shift positions
C)he had relatively little evidence supporting the existence of a supercontinent
D)the apparent fit of continental coastlines is blurred when the margins are defined by the edges of continental shelves rather than sea level

Question 8

Evidence that glaciers once covered an area might include ________.

A)till and striations
B)backwash and striations
C)till and grabens
D)backwash and grabens

Question 9

The apparent tendency of the north (or south)magnetic pole to vary in position over time is termed ________.

A)dipole
B)magnetic declination
C)magnetic inclination
D)polar wander

Question 10

Wegener's evidence for a united Pangaea comes from the fossil record of which type of organisms?

A)plant pollen
B)plankton
C)marine animals
D)land animals

Question 11

If a geologist discovered coal in a modern-day cold,snowy location,he or she could conclude that ________.

A)a meteorite must have struck the area
B)the area was once covered with swamps and/or jungles
C)the area was once covered with an ocean
D)this discovery was anomalous

Question 12

Evidence that the South American and African continents were once joined includes evidence from their coastlines such as ________.

A)shared anthropological evidence
B)identical mineral properties
C)symmetrical earthquake patterns
D)matching fossil distributions

Question 13

As shown below,Wegener proposed continental drift after he observed evidence from fossils,glacial deposits,and the fit of the continents that suggested all of the continents were once ________.

A)aligned north to south along the prime meridian
B)aligned east to west along the equator
C)combined to form a supercontinent he termed Rodinia
D)combined to form a supercontinent he termed Pangaea

Question 14

Currently,most geologists ________.

A)continue to reject continental drift
B)agree that continental drift occurs,but they still do not understand why it occurs
C)agree that continental drift occurs due to mechanisms at work in the ocean basins and upper mantle
D)agree that continental drift occurs due to mechanisms at work in the lower mantle and outer core

Question 15

Which plant genus dominated glaciated regions during the Late Paleozoic and Early Mesozoic?

A)Ginkgo
B)Glossopteris
C)Neuropteris
D)Quercas

Question 16

Distinctive rock sequences on South America terminate at the Atlantic Ocean but reappear on the continent of ________.

A)Africa
B)Europe
C)North America
D)Australia

Question 17

Consult the figure below.Abundant swamps led to the formation of coal during the Late Paleozoic in which of the following places?

A)India
B)southern Africa
C)North America
D)Antarctica

Question 18

Which of these is NOT the result of plate tectonics?

A)earthquake distribution
B)mountain building
C)formation of new oceans
D)convection in the outer core

Question 19

Wegener saw Pangaea as a jigsaw puzzle,where the puzzle pieces were ________.

A)oceans
B)continents
C)mid-ocean ridges
D)plate tectonics

Question 20

The term and concept of seafloor spreading (see figure below)was developed by ________.

A)Hess and Dietz
B)Hess and Wegener
C)Wegener and Dietz
D)Wegener

Question 21

The map below depicts earthquakes,which primarily coincide with areas where ________.

A)volcanoes also regularly occur
B)the tectonic plates are not moving
C)the geothermal heat flow is abnormally low
D)marine magnetic anomalies are not found

Question 22

Which of these parts of the deep-ocean floor is flat and nearly featureless?

A)ridge axis
B)abyssal plain
C)guyot
D)trench

Question 23

The discovery that each continent had different and separate polar-wander paths such as those in the figure below proved that ________.

A)only the continents move
B)only the poles move
C)both the poles and continents move,but independently of each other
D)both the poles and continents move,and do so together

Question 24

The apparent polar-wander path obtained from magnetite crystals in basalts on the North American continent is now interpreted to be primarily the result of ________.

A)wandering of the geomagnetic North Pole
B)drifting of the North American continent
C)the opening of the Atlantic Ocean
D)the movement of Africa away from North America

Question 25

With increasing distance from a mid-ocean ridge,the age of oceanic crust ________.

A)increases
B)decreases
C)stays constant
D)varies randomly

Question 26

If you were using both a compass and a map marked with latitude and longitude to navigate,you might note the angle difference between your compass and what is marked on the map,called ________.

A)magnetic inclination
B)magnetic declination
C)magnetic dipole
D)magnetic reversal

Question 27

Which of these statements is FALSE?

A)The continents move relative to the magnetic poles.
B)The magnetic poles move relative to the continents.
C)The polar-wander curve for each continent is unique.
D)The movement of the magnetic poles is much greater than the movement of the continents.

Question 28

Seafloor spreading is driven by volcanic activity ________.

A)in the middle of abyssal plains
B)along mid-ocean ridges
C)at the edges of continental shelves
D)along fracture zones

Question 29

Where Earth's magnetic dipole intersects with the surface of the planet is called the ________.

A)magnetic inclination
B)geographic pole
C)magnetic dipole
D)magnetic pole

Question 30

According to the figure below,Earth's magnetic poles move constantly.About how far from the geographic poles do the magnetic poles move?

A)They move as far south as the equator.
B)They move as far south as the tropics.
C)They remain in the high latitudes.
D)They remain less than a kilometer from the geographic poles.

Question 31

Volcanoes that have submerged beneath the surface of the sea are termed ________.

A)mid-ocean ridges
B)seamounts
C)fracture zones
D)continental rises

Question 32

Beneath a blanket of sediments,oceanic crust is primarily composed of ________.

A)granite
B)basalt
C)limestone
D)coal

Question 33

What does an ordinary compass indicate?

A)magnetic inclination
B)magnetic declination
C)magnetic north
D)true north

Question 34

Which mineral is integral to paleomagnestim?

A)magnetite
B)iron
C)quartz
D)potassium feldspar

Question 35

The thickness of clay and planktonic microskeletons is greatest ________.

A)along mid-ocean ridges
B)along fracture zones
C)at the edges of ocean basins
D)in the center of abyssal plains

Question 36

Within the sea floor,the rate of geothermal heat flow is greatest ________.

A)along mid-ocean ridges
B)along fracture zones
C)at the edges of ocean basins
D)in the center of abyssal plains

Question 37

Evidence of paleomagnetism can be found in ________.

A)basalt that has cooled from lava
B)any rock with magnetic minerals present
C)sedimentary rocks where minerals form from ion-bearing groundwater
D)All of the above are correct.

Question 38

Deep-ocean trenches are found predominantly along the perimeter of the ________ .

A)Indian Ocean
B)Pacific Ocean
C)Atlantic Ocean
D)Arctic Ocean

Question 39

The oldest basalts on the ocean floor are about ________ years old.

A)50 thousand
B)4 billion
C)200 million
D)2.5 million

Question 40

A great boost in seafloor exploration and a greater understanding of seafloor bathymetry was a result of ________.

A)scientific advances in the 1950s
B)scientific advances in the 1920s
C)military needs in World War I
D)military needs in World War II

Question 41

Regions of the sea floor with negative magnetic anomalies were formed during times when Earth's magnetic field ________.

A)was exceptionally strong
B)was exceptionally weak
C)had normal polarity
D)had reversed polarity

Question 42

Marine magnetic anomaly belts run parallel to ________.

A)mid-ocean ridges
B)fracture zones
C)continental coastlines
D)continental shelves

Question 43

Regions of the sea floor with positive magnetic anomalies were formed during times when Earth's magnetic field ________.

A)was exceptionally strong
B)was exceptionally weak
C)had normal polarity
D)had reversed polarity

Question 44

Earth's magnetic reversals are likely due to ________.

A)meteorite impacts
B)lightning strikes
C)tectonic plates shifting
D)changes in circulation patterns in the inner core

Question 45

Spreading rates along mid-ocean ridges have ________.

A)been remarkably constant through time
B)changed through time,but are the same everywhere on Earth today
C)changed through time,and today vary between 1 and 10 m/yr
D)changed through time,and today vary between 1 and 10 cm/yr

Question 46

By deep-sea drilling,the Glomar Challenger proved the theory that if the model of seafloor spreading was correct,then seafloor sediment should be ________ and ________ as one moves away from the spreading axis.

A)thicker;younger
B)thicker;older
C)thinner;younger
D)thinner;older

Question 47

All basalts younger than 700,000 years old ________.

A)have normal magnetic polarity
B)have reverse magnetic polarity
C)are found on the ocean floor very far from mid-ocean ridges
D)are found on the continents

Question 48

According to the figure below,marine magnetic anomalies lay roughly ________ to mid-ocean ridges.

A)perpendicular
B)parallel
C)adjacent
D)at an obtuse angle

Question 49

Marine magnetic anomalies result from seafloor spreading in conjunction with ________.

A)global warming
B)magnetic storms on the surface of the Sun
C)magnetic polarity reversals
D)apparent wander of the magnetic poles

Question 50

Consult the figure below.Marine magnetic anomaly belts are widest when and where ________.

A)continents are joined to form supercontinents
B)seafloor spreading rates are relatively rapid
C)seafloor spreading rates are relatively slow
D)supercontinents first began to rift apart