Deck 3: Drifting Continents and Spreading Seas

Question 1

The theory of plate tectonics is a theory because it _____________.

A)was discovered so long ago
B)is widely accepted
C)is not widely accepted
D)cannot be directly proven

Answer 1

D

Question 2

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

Answer 2

B

Question 3

According to Wegener,puzzle pieces are to a jigsaw puzzle as ____________ is/are to Pangaea.

A)continental drift
B)continents
C)sea-floor spreading
D)plate tectonics

Answer 3

B

Question 4

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 5

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

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

Question 6

The magnetic field of Earth in the geologic past is ____________.

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

Question 7

Evidence for a united Pangaea comes from the fossil record of which type(s)of organisms?

A)plants
B)large terrestrial animals
C)freshwater animals
D)All of the above are correct.

Question 8

Wegener's evidence for a united Pangaea was so compelling that virtually all geologists agreed with the idea of continental drift during his lifetime.

Question 9

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 10

Without plate tectonics,we would not have _______________.

A)plates in constant motion
B)mountain building
C)formation of new oceans
D)All of the above are correct.

Question 11

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 during the Late Cenozoic
B)aligned east to west along the equator during the Late Mesozoic through the Cenozoic
C)combined to form a supercontinent (he termed Rodinia)in the Proterozoic
D)combined to form a supercontinent (he termed Pangaea)in the Late Paleozoic through the Mesozoic

Question 12

The term and concept of sea-floor spreading (see figure below)was developed by _____________.

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

Question 13

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 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;the mechanisms that drive drift are at work in the ocean basins and upper mantle and were unknown in Wegener's time
D)agree that continental drift occurs;the mechanisms that drive drift are at work in the lower mantle and outer core and were unknown in Wegener's time

Question 15

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 16

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)South America

Question 17

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

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

Question 18

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

Question 19

In Wegener's evidence for continental drift,continents were proposed to fit together,such as the east coast of South America with the __________________ and the upper west coast of Africa with the _______________.

A)west coast of Europe;east coast of South America
B)lower west coast of Africa;east coast of South America
C)west coast of Europe;east coast of North America
D)lower west coast of Africa;east coast of North America

Question 20

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)imply that ancient human societies had access to good snorkeling and premium margaritas

Question 21

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 22

It is not the continents that move relative to a fixed pole,but rather it is the pole that moves relative to fixed continents.

Question 23

An average everyday compass depicts inclination.

Question 24

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

A)wandering of the geomagnetic North Pole
B)drifting of the North American continent

Question 25

This map depicts earthquakes,which coincide with areas where ___________.

A)volcanoes also regularly occur
B)movements of the crust take place
C)rocks break and move
D)All of the above are correct.

Question 26

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 27

According to the figure below,fracture zones lay roughly ___________ to mid-ocean ridges.

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

Question 28

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

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

Question 29

The discovery that each continent had different and separate polar wander paths proved that _____________.

A)Wegener was right: continents move
B)the poles move
C)both the poles and continents move

Question 30

Sea-floor 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 31

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 32

A compass today points directly to geographic north.

Question 33

According to the figure below,Earth's magnetic poles move constantly,but don't seem to stray farther than about ____________ from the geographic poles.

A)500 km
B)1,000 km
C)1,500 km
D)2,000 km

Question 34

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 35

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 36

Deep ocean trenches are found predominantly along the perimeter of the _____________ and can reach depths up to ____________,deep enough to swallow Mount Everest.

A)Pacific Ocean;4-10 km
B)Pacific Ocean;8-12 km
C)Atlantic Ocean;4-10 km
D)Atlantic Ocean;8-12 km

Question 37

What mineral is integral to paleomagnestim?

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

Question 38

A great boost in sea-floor exploration and a greater understanding of sea-floor 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 39

The deep ocean floor is flat and nearly featureless.

Question 40

The age of oceanic crust ____________ with increasing distance from a mid-ocean ridge.

A)increases
B)decreases

Question 41

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 42

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 43

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 44

Marine magnetic anomaly belts run parallel to ____________.

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

Question 45

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 46

Beneath a blanket of sediments,oceanic crust is primarily composed of two rocks,____________ and ____________.

A)granite;diorite
B)gabbro;basalt
C)sandstone;shale
D)slate;gneiss

Question 47

Marine magnetic anomalies result from sea-floor 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 48

By deep-sea drilling,the Glomar Challenger proved the theory that if the model of sea-floor spreading was correct,then sea-floor 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 49

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 50

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

A)continents are joined to form supercontinents
B)sea-floor spreading rates are relatively rapid
C)sea-floor spreading rates are relatively slow

Question 51

According to the figure below,the Earth's magnetic reversals are likely due to ______________.

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