Deck 9: Geologic Time

Question 1

In this photograph,Paleozoic sandstone rests depositionally on Precambrian granite.What events must have occurred before deposition of the sandstone?

A)uplift of granite to the surface
B)solidification of granite at depth
C)formation of an erosion surface
D)all of these
E)none of these

Answer 1

D

Question 2

What kind of geologic feature is shown in this photograph?

A)contact metamorphism
B)unconformity
C)desert varnish
D)desert pavement
E)none of these

Answer 2

D

Question 3

What is the main geologic feature for which Siccar Point in Scotland is famous?

A)a boundary between steep gray layers below and gently dipping red layer above
B)an unconformity
C)an ancient erosion surface
D)all of these
E)none of these

Answer 3

D

Question 4

Which numbered layer in this photograph represents the oldest layer?

A)1
B)2
C)3
D)4

Question 5

What type of feature is shown in this photograph of Siccar Point,Scotland?

A)monocline
B)thrust fault
C)normal fault
D)unconformity

Question 6

Which sequence of numbers reflects the order in which the layers were deposited?

A)1,2,3,4
B)1,3,4,2
C)4,3,2,1
D)4,3,1,2
E)none of these

Question 7

What is the youngest event represented in this block diagram?

A)formation of the lowest layer
B)deposition of the top layer
C)erosion of a canyon by a river
D)retreat of the seas

Question 8

Where is the oldest layer in this tilted sequence of sedimentary rocks?

A)at the top of the hill in the center of the photograph
B)the darkest layers will be the oldest
C)the layers on the lower left part of the photograph
D)the layers on the right of the photograph

Question 9

The highest surface on this figure is a river terrace.This terrace:

A)is older than the modern river channel
B)formed sometime in the past
C)predates erosion down to the present level
D)all of these

Question 10

What is a principle we use to determine the age of a landscape surface?

A)A landscape surface must be older than any rocks onto which it is carved.
B)A landscape surface is younger than any rock that is deposited on top of the surface.
C)The highest river terrace is probably the youngest in age.
D)A surface with a well-developed soil is probably older than a surface with no soil.

Question 11

What kind of geologic feature is shown in this photograph?

A)contact metamorphism
B)unconformity
C)desert varnish
D)desert pavement
E)none of these

Question 12

Which of the four numbered features on this figure is the oldest?

A)1
B)2
C)3
D)4

Question 13

Which numbered layer in this photograph represents the youngest layer?

A)1
B)2
C)3
D)4

Question 14

This photograph shows an upper unit with fragments and a lower unit with tilted layers.Which of the following statements is true?

A)the upper unit is younger because it is on top
B)the upper unit is younger because it contains pieces of the underlying unit
C)the lower unit is older because it was tilted and eroded before deposition of the upper unit
D)all of these

Question 15

Which of the four sedimentary layers in this figure is the oldest?

A)the layer on top
B)the layers in the middle
C)the layer on bottom
D)there is not enough information to tell

Question 16

This photograph shows light-colored granite and darker diorite (both igneous rocks).Which of the following statements is true?

A)the light-colored unit is younger because granite is more continental than diorite
B)the diorite is older because its weathered surfaces are darker
C)the granite is younger because it crosscuts the diorite
D)all of these

Question 17

Which of the four numbered features on this figure is the youngest?

A)1
B)2
C)3
D)4

Question 18

This photograph shows an upper light-colored conglomerate and a lower dark basalt.Which of the following statements is true?

A)the conglomerate is older because it overlies the dark basalt
B)the conglomerate is younger because it contains clasts of the dark basalt
C)the basalt is younger because it is crosscut by fractures filled with conglomerate
D)none of these

Question 19

The geologic relationships in this figure indicate that the lava flow:

A)pushed the trees over
B)overlies an angular unconformity
C)is younger than the landscape surface partially covered by the lava flow
D)that materials beneath the lava flow were uplifted from great depth

Question 20

What type of feature is represented by the boundary between geologic units 2 and 3?

A)cleavage
B)unconformity
C)anticline
D)joint

Question 21

This figure shows the main subdivisions of the geologic timescale.Which of these is the Paleozoic?

A)A
B)B
C)C
D)D

Question 22

If a rock started with 1,000 atoms of a parent but now contains 250 atoms,how many half lives have passed?

A).25 half lives
B).5 half lives
C)1 half life
D)2 half lives
E)there is no way to tell

Question 23

The fossil fern in this photograph probably indicate that the rock was deposited:

A)by the wind
B)in the deep ocean
C)in the shallow ocean
D)on land

Question 24

How does an angular unconformity form?

A)rocks are folded into an angle and the top is removed by faulting
B)older rocks are tilted,eroded,and overlain by younger rocks
C)rock layers are turned upside down at an angle
D)angular rocks are deposited on top of flat-lying layers
E)any of these

Question 25

Which of the following is NOT something we can learn by determining isotopic ages?

A)the age of a volcanic eruption
B)the age when a rock is uplifted toward the surface
C)the age of material from which clasts in a sedimentary rock were derived
D)the cooling history by using different types of isotopic ages
E)we can determine all of these

Question 26

This figure shows the main subdivisions of the geologic timescale.Which of these is the Precambrian?

A)A
B)B
C)C
D)D

Question 27

This figure shows the main subdivisions of the geologic timescale.Which of these is the Mesozoic?

A)A
B)B
C)C
D)D

Question 28

What factors are the most critical in determining whether a fossil is preserved?

A)the age of the fossil and the age of sediments in which it is preserved
B)the temperature of the granite and how fast it cooled
C)whether the creature had hard parts and how fast it was buried
D)the color of the original organism compared to the color of the sediments in which it is found
E)whether the creature was a predator or was prey

Question 29

The impressions of fossil shells in this photograph probably indicate that the rock was deposited:

A)by the wind
B)in the sea
C)in a dry climate
D)in a forest

Question 30

Which of the following is the earliest (oldest)chapter of geologic time?

A)Cenozoic
B)Mesozoic
C)Paleozoic
D)Precambrian

Question 31

This figure shows a disconformity between an upper dark layer (being deposited by the sea)and a lower light-colored layer.What happened to form this disconformity?

A)The lower layers were tilted and untilted before deposition of the upper layers.
B)The boundary between the two units indicates that for a time there was either erosion or no deposition.
C)The lower limestones were converted into another rock type by seawater.
D)The upper layer must have been deposited by volcanic eruptions.

Question 32

To what does the term evolution refer?

A)observed changes in the fossil record
B)to one or more theories that help explain observed changes
C)as a general term to describe how something,such as a landscape,has changed over time
D)all of these

Question 33

This figure shows the main subdivisions of the geologic timescale.Which of these is the Cenozoic?

A)A
B)B
C)C
D)D

Question 34

Which of the following features look like fossils but are not?

A)footprints from dinosaurs and other creatures
B)burrows excavated by worms and other creatures and filled by other sediment
C)leaves and other plants formed on land
D)dark minerals that grow in branching patterns
E)all of these are fossils

Question 35

In which of the following time periods were mammals the dominant type of life?

A)Cenozoic
B)Mesozoic
C)Paleozoic
D)Precambrian

Question 36

In which of the following time periods did coral,clams,fish,plants and insects become abundant?

A)Cenozoic
B)Mesozoic
C)Paleozoic
D)Precambrian

Question 37

If the contact between the upper light-colored sedimentary layers and the lower dark-colored metamorphic rocks is a depositional contact,what type of feature is present?

A)a surface representing missing geologic time
B)an angular unconformity
C)an ancient erosion surface
D)all of these

Question 38

Which of the following time periods were dinosaurs the dominant creatures?

A)Cenozoic
B)Mesozoic
C)Paleozoic
D)Precambrian

Question 39

The term half life represents the time it takes:

A)to dissolve half of the atoms in the lattice
B)for the parent atoms to decay into atoms half their original size
C)for half of the parent atoms to decay into daughter atoms
D)for the Sun to decrease its size by 50 percent

Question 40

Which of the following is NOT a way in which fossils can be preserved?

A)They can be replaced by hard materials,such as silica.
B)They can be buried and decay,leaving a cavity in the rock.
C)They can be preserved in ancient tree sap.
D)They can be too small to see but can build diagnostic features in the rocks.
E)All of these are ways a fossil can be preserved.

Question 41

This figure shows two sections of rocks.What is the youngest unit?

A)unit 1
B)unit 4
C)unit 6
D)unit 9
E)none of these

Question 42

Which of the following chapters in geologic time occurred before there were abundant animals with hard parts?

A)Cenozoic
B)Mesozoic
C)Paleozoic
D)Precambrian

Question 43

Which of the following collection of fossils would be LEAST useful for determining the age of a section of rocks?

A)fossils that are large and distinctive
B)fossils that are widely distributed across different parts of Earth
C)the fossil of a family of creatures that lived unchanged for a very long time
D)index fossils

Question 44

This figure shows the geologic timescale.Which period listed below would be part of the Paleozoic?

A)Permian
B)Pennsylvanian
C)Mississippian
D)Cambrian
E)all of these

Question 45

Which of the following is evidence that Earth's history is not short?

A)millions of layers of light- and dark-colored sediment that record yearly cycles
B)rates of seafloor spreading compared to the width of the Atlantic Ocean
C)a 4-billion-year age on a rock in Canada
D)thousands of isotopic ages measured by different methods
E)all of these

Question 46

What would fossil ages from the geologic timescale tell us about the age of this unconformity?

A)The unconformity is younger than the fossil ages on the tilted bed.
B)The unconformity is older than the fossil ages in layers above the unconformity.
C)The amount of time represented by the unconformity can be approximately bracketed by the ages of the fossils above and below.
D)All of these.

Question 47

The contact at the base of unit F in both columns:

A)is a disconformity
B)represents erosion or no deposition
C)represents some missing time
D)all of these

Question 48

This figure shows the geologic timescale.Which period listed below would be part of the Mesozoic?

A)Neogene
B)Jurassic
C)Pennsylvanian
D)Mississippian
E)Cambrian

Question 49

This figure shows two sections that represent the same age range and contain some of the same fossils.If you compare the two sections,what conclusions do you come to?

A)Some of the fossils must have had a limited geographic distribution.
B)Some units were deposited in the left section but not in the right one or were eroded away.
C)The thickness of the units are consistent between the two sections.
D)All of these.
E)None of these.

Question 50

Upon what basis were the upper and lower boundaries of the Mesozoic Era defined?

A)dramatic changes in the color of the rocks from green to tan
B)major episodes of mountain building
C)abrupt changes in the types of fossils,representing mass extinctions
D)the discovery that a meteoroid impact may have killed the dinosaurs

Question 51

How would we use isotopic ages to infer the ages of the upper and lower unit in this diagram?

A)The lower unit would be younger than an age on the crosscutting dike.
B)The upper unit would be older than an age determined on pebbles of the dike in that unit.
C)The dike is younger than the lower unit but older than the upper unit.
D)An age on the dike would not help us because it is an igneous rock.

Question 52

This figure shows the geologic timescale.Which period listed below would be part of the Paleozoic?

A)Neogene
B)Paleogene
C)Jurassic
D)Triassic
E)Cambrian

Question 53

Which of the following forms different layers from season to season and can be used to determine how many years the layers represent?

A)tree rings
B)layers in ice cores
C)varves
D)all of these

Question 54

Unit C is present in the left column but not the right column because:

A)rocks in the right column were tilted and eroded
B)it was not deposited or was eroded away
C)it has different kinds of fossils than rocks in the right column
D)all of these

Question 55

This figure shows the geologic timescale.Which period listed below would be part of the Cenozoic?

A)Neogene
B)Jurassic
C)Triassic
D)Pennsylvanian
E)Cambrian

Question 56

This art work shows life on the sea bottom,at a time when fishes and creatures with shells appeared on Earth.What time period is represented?

A)Mesozoic
B)Cenozoic
C)Precambrian
D)Paleozoic

Question 57

Why don't these two sequences of fossil-bearing rocks match exactly?

A)they represent different parts of geologic time
B)one section was tilted but not the other
C)they have different histories of erosion and deposition
D)one represents a transgression whereas the other represents a regression

Question 58

This figure shows two sections that partially overlap in age.Dashed lines show how the two sections correlate.What can you conclude from these correlations?

A)the oldest unit is unit 4
B)the youngest unit is unit 6
C)the rate at which unit 5 was deposited was constant across the area
D)the left section represents older rocks than the right section
E)none of these

Question 59

What would fossil ages from the geologic timescale and an isotopic age on the granite tell us about the age of the unconformity?

A)The unconformity is older than the isotopic age of the granite.
B)The unconformity is older than the age assigned to the fossils.
C)The granite is younger than the unconformity.
D)It is not possible to have fossils preserved so close to granite.
E)None of these.

Question 60

Which of the following is NOT accurately dated at between 4 and 4.6 billion years old?

A)the oldest dates on mineral grains on Earth
B)age of the oldest meteorites
C)age of moon rocks returned to Earth and dated
D)isotopic ages on Earth's oldest known fossil shell

Question 61

This figure shows two sections of rocks.Which of the following is NOT a valid way to correlate one of the numbered units from one section to another?

A)Units at the top of two sections will automatically be correlative.
B)A distinctive rock type (breccia in unit 4)is probably equivalent to the same rock type in the other section.
C)Match units that contain the same types of index fossils (as in unit 3).
D)The shale in unit 2 is part of a distinctive sequence that is overlain by the same type of fossils.

Question 62

In this diagram the contact between the granite (unit 1)and the lowest layer (unit 2)is depositional.What is the youngest unit?

A)the lava flow (unit 11)
B)the fault (unit 10)
C)highest layer (unit 5)
D)lowest layer (unit 2)
E)granite (unit 1)

Question 63

In this diagram,the contact between the granite (unit 1)and the lowest layer (unit 2)is depositional and the dike (unit 6)cuts across both units.What is the oldest unit?

A)the lava flow (unit 11)
B)the fault (unit 10)
C)the dike (unit 6)
D)lowest layer (unit 2)
E)granite (unit 1)

Question 64

What types of life developed during the Paleozoic?

A)corals,crinoids,and other creatures with shells
B)trilobites
C)fish and amphibians
D)plants and insects
E)all of these

Question 65

What time period is represented by this scene?

A)Mesozoic
B)Cenozoic
C)Precambrian
D)Paleozoic

Question 66

What were some of the earliest forms of life on Earth?

A)land plants and insects
B)corals and other bottom-dwelling sea creatures
C)microscopic creatures that built mound-shaped structures called stromatolites
D)sharks

Question 67

Of the following numbered units,which is the oldest?

A)a sedimentary layer (2)
B)the granite (4)
C)gravels along the river (7)
D)the volcano and lava flow (9)
E)the highest sedimentary layer (11)

Question 68

Which numbered feature in this figure is the oldest?

A)the upper volcanic unit (1)
B)limestone (2)
C)sandstone (3)
D)metamorphic rocks (4)
E)granite (5)

Question 69

This figure shows two sections of rocks.What is the surest way to correlate a unit in one section to a unit in the other section?

A)match the similar sequence of rocks
B)find a distinctive unit in both sections
C)find two layers that both contain fossils
D)physically trace a unit through the landscape from one section to another

Question 70

What time period is represented by this scene?

A)Mesozoic
B)Cenozoic
C)Precambrian
D)Paleozoic

Question 71

Which of the following might help determine the age of the volcanic features in this figure?

A)numeric ages
B)how well the shapes of the volcanoes are preserved
C)how well developed soil is on the lava flows
D)all of these

Question 72

Which of the following is a reason why rock units may change from one section to another?

A)facies change
B)restricted aerial distribution
C)removed along an unconformity or disconformity
D)eroded away
E)all of these

Question 73

What is a possible cause of the extinction event called the Great Dying?

A)a meteorite impact that killed the dinosaurs
B)a great outpouring of lava at the end of the Paleozoic
C)a sudden increase in the oxygen content of the atmosphere during the Precambrian
D)a new kind of super predator that devoured nearly all of the life in the oceans

Question 74

Of the following numbered units,which is the youngest?

A)a sedimentary layer (2)
B)the fault and fault scarp (3)
C)a sedimentary layer (5)
D)the volcano and lava flow (9)
E)the highest sedimentary layer (11)

Question 75

What marks the boundary between the Mesozoic and the Cenozoic (called the K-P boundary)?

A)the extinction of the dinosaurs
B)the start of a rise to dominance of mammals
C)a meteorite impact in Mexico
D)all of these
E)none of these

Question 76

If you were trying to correlate these two sequences of rocks,what would probably be the most straightforward strategy to use?

A)determine numeric ages on pieces of rock in the landslide on top
B)compare the fossils of the middle layers
C)compare the thicknesses of the middle layer
D)compare the thicknesses of the lower layer

Question 77

Of the following numbered units,which is the youngest?

A)unit 4
B)unit 5
C)unit 6
D)unit 9
E)unit 11

Question 78

What was the Cambrian explosion?

A)a large volcano that went off in Wales,which the Romans called Cambria
B)a meteorite impact that struck the north coast of the Yucatan Peninsula of Mexico
C)a time when a meteorite collided with the center of a supercontinent,melting all the glaciers
D)a time when many different types of creatures appeared on Earth

Question 79

Which of the following did NOT live during the Mesozoic era?

A)dinosaurs that had a bird-like hip
B)dinosaurs with a hip structure similar to lizards
C)large flying reptiles
D)large marine reptiles
E)all of these lived during the Mesozoic

Question 80

Which of the following would be LEAST useful in correlating the ages of these two sequences of rocks?

A)numeric ages on the volcanic rocks on top
B)the pattern of magnetic reversals (R and N)
C)the overall sequence of the upper three layers
D)the type of material present in the landslide at the bottom of the right column