Deck 10: History of the Continents

Question 1

How thick is the sequence of sedimentary rocks that comprises the Great Plains?

A)several tens of meters thick
B)several kilometers thick
C)several hundreds of meters thick
D)several tens of kilometers thick

Answer 1

B

Question 2

The oldest continental crust contains rocks as old as

A)400 million years.
B)50 million years.
C)40 billion years.
D)4 billion years.

Answer 2

D

Question 3

Oceanic crust provides a record of approximately ___ of Earth's history.

A)4%
B)25%
C)75%
D)95%

Answer 3

A

Question 4

The geologic events preserved in the Canadian Shield took place mainly during the

A)Archean eon.
B)Paleozoic era.
C)Phanerozoic eon.
D)Mesozoic era.

Question 5

Which of the following regions contains numerous fault-block mountain ranges?

A)the Appalachians
B)the Canadian Shield
C)the Basin and Range province
D)the Great Plains

Question 6

Why is the North American Cordillera topographically higher than the Appalachians?

A)because the Appalachians have undergone less erosion
B)because the Cordillera formed by continent-continent collision
C)because the main orogeny in the Cordillera was more recent
D)because the spreading rate of the East Pacific Rise is greater than the spreading rate of the Mid-Atlantic Ridge

Question 7

In which of the following regions would you expect to find the thickest sequence of sedimentary rocks?

A)along mid-ocean ridges
B)in the middle of the ocean basin,away from a ridge
C)on continental platforms
D)on continental shelves

Question 8

What type of geologic contact separates the rocks of the Canadian Shield from the rocks of the Great Plains? (Hint: Consider the type and age of the rocks found in each area.)

A)intrusive contact
B)strike-slip fault
C)thrust fault
D)unconformity

Question 9

Which of the following is not a common rock type in the Canadian Shield?

A)gneisses
B)granitic rocks
C)highly deformed metamorphosed volcanic rocks
D)undeformed sedimentary rocks

Question 10

The present-day topography of the Basin and Range province formed during ______ time.

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

Question 11

The North American Cordillera formed over a period of

A)2 million years.
B)10 million years.
C)50 million years.
D)200 million years.

Question 12

Cratons are made up of

A)orogens and platforms.
B)platforms and shields.
C)orogens and shields.
D)orogens,platforms,and shields.

Question 13

Which of the following processes is responsible for the topography of the Basin and Range province in western North America?

A)normal faulting
B)strike-slip faulting
C)thrust faulting
D)upwarping

Question 14

What is meant by the tectonic age of a region?

A)the oldest rocks in the region
B)the oldest major deformation event in the region
C)the youngest rocks in the region
D)the youngest major deformation event in the region

Question 15

Which of the following geologic events occurred most recently?

A)the collision of Laurasia and Gondwana
B)the faulting of the Basin and Range province
C)the initial rifting of the Atlantic Ocean
D)the magmatism in the Canadian Shield

Question 16

Most of the rocks of the interior platform of North America were deposited in a(n)

A)continental rift.
B)extensive shallow sea.
C)deep-ocean basin.
D)volcanic island arc.

Question 17

What mountain chain runs along the eastern margin of North America?

A)the Andes
B)the Appalachians
C)the Caledonides
D)the Cordillera

Question 18

Where are the oldest rocks in North America located?

A)in the Appalachian Mountains
B)in the Canadian Shield
C)in the Basin and Range province
D)in the Rocky Mountains

Question 19

The Blue Ridge province of the Appalachian fold belt was thrust as sheets over the top of which geologic province?

A)the Appalachian Plateau province
B)the Piedmont province
C)the Coastal Plain province
D)the Valley and Ridge province

Question 20

How far do continental deformation zones,like the Cordilleran orogenic belt,extend from a plate boundary?

A)a few kilometers
B)a few hundreds of kilometers
C)a few tens of kilometers
D)approximately 1000 kilometers

Question 21

Which of the following terms refers to the gradual vertical movements of the crust without significant deformation?

A)accretion
B)epeirogeny
C)orogeny
D)rejuvenation

Question 22

Which of the following mountain chains was the result of a continental collision during the assembly of the supercontinent Pangaea?

A)the Andes
B)the Appalachians
C)the Cordillera
D)the Himalayas

Question 23

The Cordillera of western North America formed as a result of

A)the collision of a large continental landmass with western North America.
B)the extension of the western North American continental crust.
C)the collision of numerous exotic terrains with western North America.
D)motion along the San Andreas Fault.

Question 24

In which of the following regions is new material currently being added to the crust?

A)the Appalachian Mountains
B)the Cascade Range
C)the Canadian Shield
D)the Rocky Mountains

Question 25

Which of the following best describes the type of rocks that make up Wrangellia,an exotic terrain in western North America?

A)continental fragment
B)island arc
C)oceanic plateau
D)oceanic fragment

Question 26

How thick is the crust of the Tibetan plateau?

A)10 to 20 km thick
B)30 to 40 km thick
C)60 to 70 km thick
D)100 to 150 km thick

Question 27

What is an orogeny?

A)a broad exposure of deformed metamorphic and igneous rocks
B)a general term for mountain-building processes
C)a special type of reverse fault
D)a theory that explains the uplift of continents after large ice sheets melt

Question 28

Over the past 4 billion years,which of the following best describes how the volume of the continents has changed?

A)The volume of the continents has decreased by approximately 100 cubic kilometers per year.
B)The volume of the continents has remained approximately constant.
C)The volume of the continents has increased by approximately 2 cubic kilometers per year.
D)The volume of the continents has increased by approximately 100 cubic kilometers per year.

Question 29

Which of the following orogenies represents the final assembly of Pangaea?

A)Acadian orogeny
B)Caledonian orogeny
C)Appalachian orogeny
D)Taconic orogeny

Question 30

Which of the following sequences describes the Wilson cycle?
I.continent-continent collision
II.continental rifting
III.sea-floor spreading
IV.subduction

A)I,IV,II,III
B)III,I,IV,II
C)II,III,IV,I
D)IV,II,III,IV

Question 31

Which of the following mountain belts formed as a result of a collision between two continents?

A)the Appalachians
B)the Himalayas
C)the Urals
D)all of the above

Question 32

The Himalayas began to form approximately ______ when the Indian subcontinent began to collide with Tibet.

A)5 million years ago
B)50 million years ago
C)500 million years ago
D)5 billion years ago

Question 33

When did plate tectonics and the Wilson cycle begin?

A)approximately 0.5 billion years ago
B)approximately 2.5 billion years ago
C)approximately 1.0 billion years ago
D)approximately 4.0 billion years ago

Question 34

The Himalayas consist primarily of

A)basaltic lava flows and gabbroic intrusions.
B)gently folded sedimentary rocks.
C)granitic to dioritic plutons and related volcanic rocks.
D)thrust sheets of deformed and metamorphosed sedimentary rocks.

Question 35

The main thrust sheets in the Himalayas were transported

A)northward.
B)southward.
C)eastward.
D)westward.

Question 36

Which of the following is not a cause of epeirogenic movement?

A)glacial rebound
B)lithospheric cooling
C)lithospheric heating
D)ocean-continent convergence

Question 37

Which of the following regions is an example of an epeirogenic uplift?

A)the Appalachian Mountains
B)the Rocky Mountains
C)the Colorado Plateau
D)the Sierra Nevada

Question 38

When did the three main orogenies that formed the Appalachian Mountains occur?

A)during the Cenozoic era
B)during the Paleozoic era
C)during the Mesozoic era
D)during Precambrian time

Question 39

Prior to the collision of India and Asia,oceanic crust was subducted beneath

A)Asia.
B)India.
C)both Asia and India.
D)neither Asia nor India.

Question 40

Which of the following statements is true?

A)India is colliding with Asia at a rate of approximately 4 millimeters per year.
B)India is colliding with Asia at a rate of approximately 4 centimeters per year.
C)India is colliding with Asia at a rate of approximately 4 meters per year.
D)India is no longer colliding with Asia.

Question 41

What is the likely age of diamonds brought up in xenoliths of cratonic keels?

A)several million years
B)50 million years
C)100 million years
D)billions of years

Question 42

The present day Himalayan orogeny is considered similar to the __________ orogeny.

A)Appalachian
B)Taconic
C)Grenville
D)Caledonian

Question 43

The collision of India with Eurasia thrust China and Mongolia

A)westward.
B)northward.
C)eastward.
D)southward.

Question 44

An orogenic belt on Earth that is still actively growing today is

A)the North American Cordillera.
B)the Alpine-Himalayan belt.
C)the Appalachian Fold belt.
D)the Variscan Fold belt.

Question 45

The geologically stable areas of continental crust are referred to as

A)platforms.
B)orogens.
C)cratons.
D)provinces.

Question 46

Which tectonic plate subducted beneath western North America as it was moving westward following the breakup of Pangea?

A)the Farallon Plate
B)the Cocos Plate
C)the Juan de Fuca Plate
D)the Pacific Plate

Question 47

What is the name of the supercontinent that assembled during the late Proterozoic?

A)Pangea
B)Appalachia
C)Laurentia
D)Rhodinia

Question 48

How many mountain-building episodes are recognized in the Valley and Ridge province of the Appalachian fold belt?

A)one
B)two
C)three
D)four

Question 49

How far has India penetrated into Eurasia?

A)a few hundred meters
B)a few thousand meters
C)100 kilometers
D)a few thousand kilometers

Question 50

What would happen to cratonic keels if they had the same chemical composition as ordinary mantle peridotites?

A)They would melt.
B)They would float.
C)They would sink.
D)Nothing would happen.

Question 51

Which of the following regions is considered tectonically stable?

A)Appalachians
B)Gulf of Mexico
C)Rocky Mountains
D)Greenland

Question 52

During the so-called Wilson cycle,which of the following is least affected?

A)ocean basins
B)accreted terrains
C)continental margins
D)cratons

Question 53

How might plate tectonic processes have been different in the Archean?

A)The plates moved more rapidly.
B)The plates were much larger.
C)The plates moved more slowly.
D)There was no subduction.

Question 54

Cratonic keels are

A)thinner under continents than oceans.
B)of even thickness everywhere.
C)thinnest under cratons.
D)thicker under continents than oceans.

Question 55

When did the Basin and Range province begin to form?

A)150 million years ago
B)5 million years ago
C)100 million years ago
D)15 million years ago

Question 56

Evidence of a hotter mantle in the Archean comes from _________ volcanic rock,which is found only in Archean crust.

A)peridotite
B)ultramaficite
C)komatiite
D)rhyolite

Question 57

What type of evidence supports the existence of liquid surface water 4.4 billion years ago?

A)oxygen isotopic composition of zircons
B)radiometric dating of zircons
C)chemical composition of the Acasta gneiss
D)the age of the Acasta gneiss

Question 58

Which of the following regions has the thickest lithosphere?

A)Archean cratons
B)oceans
C)Cenozoic orogenic belts
D)Paleozoic orogenic belts

Question 59

Which tool has been a great aid in deciphering the history of continental rocks?

A)seismic profiling
B)geologic mapping
C)isotopic dating
D)stratigraphy

Question 60

The process whereby continents grow as a result of continental collisions is called

A)accretion.
B)differentiation.
C)assimilation.
D)fractionation.

Question 61

When large areas of continental crust are tectonically stable they

A)experience intense rifting.
B)develop mountain ranges.
C)are eroded flat.
D)tend to be young geologically.

Question 62

Large areas of continental crust that have not experienced rifting,collisions,or uplift,but have been eroded nearly flat are known as

A)flat lands.
B)shields.
C)tectonically stable.
D)sedimentary basins.

Question 63

The tectonic age of a rock is the

A)crystallization age of that rock.
B)stratigraphic age of that rock.
C)oldest isotopic age obtained for that rock.
D)youngest isotopic age obtained for that rock.

Question 64

Glacial rebound and a superplume are both a form of

A)volcanism.
B)orgogeny.
C)epeirogeny.
D)accretion.

Question 65

The process whereby continents grow as a result of new material being added by vertical transport is called

A)accretion.
B)buoyancy.
C)assimilation.
D)magmatic addition.

Question 66

In the early Archean eon,the plate tectonic processes on Earth probably resembled those of present day

A)Mars.
B)Mercury.
C)Venus.
D)Earth.

Question 67

In what type of volcanic deposits are you most likely to find xenoliths of cratonic keels?

A)komatiite lavas
B)basalts
C)kimberlite pipes
D)andesites

Question 68

Approximately when did the first long-lasting continental crust form?

A)4 billion years
B)3 billion years
C)2 billion years
D)200 million years

Question 69

Which region of North America is tectonically stable?

A)region A
B)region B
C)region D
D)region E

Question 70

A tectonic province consisting of exposed Precambrian crystalline basement rocks that have remained undeformed for the last 542 million years is called a

A)shield.
B)platform.
C)continental basin.
D)phanerozoic orogeny.

Question 71

Crustal movement due to glacial rebound is considered to be a form of

A)orogeny.
B)accretion.
C)epeirogeny.
D)subsidence.

Question 72

What sort of tectonic province is the Basin and Range province?

A)continental basin
B)platform
C)extended crust
D)phanerozoic orogeny

Question 73

What kind of tectonic province consists of a region of Precambrian basement rocks that have a thin cover of sediments?

A)shield
B)platform
C)continental basin
D)phanerozoic orogeny

Question 74

The process whereby continents grow as a result of new material being added by horizontal transport is called

A)accretion.
B)collision.
C)wedging.
D)magmatic addition.

Question 75

The presence of ultramafic lava flows (komatiites)in the Archean suggest that mantle temperatures back then were ______ the temperatures today.

A)similar to
B)cooler than
C)much cooler than
D)hotter than

Question 76

Which of the following orogenies is oldest?

A)Appalachian
B)Taconic
C)Grenville
D)Caledonian

Question 77

What sort of tectonic province is the Appalachian fold belt?

A)extended crust
B)platform
C)continental basin
D)phanerozoic orogeny

Question 78

The oldest rock formation on the Earth is known as the

A)Canadian Shield.
B)Acasta gneiss.
C)Archean gneiss.
D)komatiite gneiss.

Question 79

Which of the following tectonic provinces contain mountains?

A)continental basin
B)platform
C)shield
D)phanerozoic orogeny

Question 80

Where is the Appalachian Fold Belt located?

A)in northern Canada
B)along the Alaskan coastline
C)in the Rocky Mountains
D)extending from Newfoundland to Alabama