Deck 13: Continental Tectonics and the Formation of the Earths Continents

Question 1

What evidence suggests that the Rocky Mountains were formed by plate convergence?

A) Giant thrusts of sedimentary rock are common.
B) Ophiolites are common.
C) Continental basalts are common.
D) Strike slip faults are common.

Answer 1

A

Question 2

Where are the Earth's oldest rocks found?

A) Continental shield.
B) Coastal plain.
C) Continental shelf.
D) Continental platform.

Answer 2

A

Question 3

Which of the following statements about continental landmasses prior to the formation of Pangaea is NOT true?

A) Laurasia became the northern half of Pangaea and included most of what is now North America and northern Europe.
B) Gondwana comprised the landmasses that eventually became the southern part of Pangaea.
C) North America sat near the South Pole, wedged between Antarctica and Australia.
D) A supercontinent named Rodinia occupied most of the Northern Hemisphere.

Answer 3

D

Question 4

Why might subduction resume in the Atlantic Ocean basin?

A) The oceanic lithosphere is very thick there.
B) The oceanic lithosphere is very old there.
C) The oceanic lithosphere is very young there.
D) The oceanic lithosphere is very thin there.

Question 5

How thick is the continental crust of North America?

A) 2 to 5 km.
B) 25 to 55 km.
C) 50 to 100 km.
D) 250 to 550 km.

Question 6

Which of the following statements concerning the basic components of continents is NOT true?

A) The shields and platforms are tectonically less active than the coastal margins.
B) The continental platform is composed of continental shield covered by a veneer of younger sedimentary rock.
C) The continental shields are composed of exposed igneous and metamorphic rocks.
D) The craton is composed of coastal mountains, coastal plains, and continental shelves.

Question 7

What plate motions are expected to occur in the geological future?

A) Africa will collide with North America.
B) Movements on the San Andreas fault will cease.
C) Rifting will cease in east Africa.
D) Australia will collide with southeast Asia.

Question 8

What type of fault is common, bounding mountains ranges, in the Basin and Range province?

A) Normal.
B) Reverse.
C) Strike slip.
D) Thurst.

Question 9

The early stages of orogeny related to tectonism are characterized by:

A) thinning of oceanic crust.
B) thinning of the continental crust.
C) mountain building and thickening of continental crust.
D) subsidence of continental crust.

Question 10

What is the geological term for mountain building?

A) Orogenesis.
B) Subduction.
C) Rifting.
D) Differentiation.

Question 11

What is the name for the process that occurred on the early Earth in which heavy materials sank to the core, and lighter materials floated to the surface?

A) Orogenesis.
B) Accretion.
C) Subduction.
D) Differentiation.

Question 12

Most of the displaced terranes of North America were accreted to the continent:

A) about 300 million years ago during the formation of the mid- Atlantic ridge.
B) about 230 million years ago during the formation of Pangaea.
C) less than 200 million years ago, after the breakup of Pangaea.
D) less than 100 million years ago, when North America collided with Wrangellia over the equator.

Question 13

The first landmasses on the Earth were probably:

A) volcanic islands.
B) felsic batholiths.
C) continental shields.
D) accretionary sediments.

Question 14

Which of the following statements concerning displaced terranes is NOT true?

A) They represent any part of a continent that is not included in the continental shield or platform.
B) They originated from somewhere other than their present locations.
C) They are distinguished from surrounding rocks by their different ages, structures, mineralogies, fossil assemblages, and magnetic properties.
D) Many formed as isolated volcanic islands or as pieces broken off from other continents.

Question 15

Where are greenstone belts found?

A) On continental shields.
B) On continental shelves.
C) On coastal plains.
D) On continental platforms.

Question 16

The continental shield of North America is composed of:

A) basaltic microcontinents.
B) Paleozoic sedimentary rocks.
C) granitic microcontinents and greenstone belts.
D) Mesozoic volcanic rocks.

Question 17

What is the source of the early Earth's atmosphere?

A) Continental collision.
B) Erosion of sediments.
C) Volcanic eruptions.
D) Rock weathering.

Question 18

The Blue Ridge province is composed of:

A) unmetamorphosed Paleozoic sedimentary rocks.
B) unmetamorphosed Paleozoic volcanic rocks.
C) highly metamorphosed Precambrian and Cambrian rocks.
D) metamorphosed coal- bearing rocks.

Question 19

The Himalayan Mountains were formed by:

A) continental collision.
B) transform faulting.
C) continental rifting.
D) hot spot volcanism.

Question 20

What was the final mountain building collision that formed the Appalachians?

A) Allegheny orogeny.
B) Acadian orogeny.
C) Catskills orogeny.
D) Taconic orogeny.

Question 21

How old are rocks in mountain belts?

A) Greater than 6 billion years.
B) Greater than 600 million years.
C) Older than shield rocks.
D) Less than 600 million years.

Question 22

What are displaced terranes? Describe and list geographic examples of displaced terranes.

Question 23

Pangaea was formed by the collision of which two landmasses?

A) Laurasia and Rodinia.
B) North America and South America.
C) Gondwana and Rodinia.
D) Gondwana and Laurasia.

Question 24

Which mountain range is still forming today?

A) Catskills.
B) Appalachian.
C) Himalaya.
D) Urals.

Question 25

Discuss the development of continental lithosphere.

Question 26

Where are the accreted terranes of eastern North America derived from?

A) Europe.
B) South America.
C) Africa.
D) Australia.

Question 27

Describe the development of Gondwana and Laurasia into Pangaea.

Question 28

Based on projections of current plate motions, what tectonic events are likely to occur in the future?

Question 29

What is the craton composed of?

A) Continental shelf and coastal plain.
B) Shield and overlying sedimentary rocks.
C) Oceanic crust.
D) Shield and continental shelf.

Question 30

What are stromatolites?

A) A type of continental collision.
B) Some of the earliest forms of life.
C) Unusual volcanic eruptions.
D) Highly deformed continental shields.

Question 31

To qualify as a mountain, at least in geological terms, an area of land must have:

A) a summit and sloping sides, and be at least 2000 feet high.
B) a summit, and be at least 1000 feet high.
C) a summit and sloping sides, and be at least 1000 feet high.
D) sloping sides, and be at least 1300 feet high.

Question 32

How was the Atlantic Ocean basin formed?

A) By continental rifting.
B) By continental collision.
C) By orogenesis.
D) By subduction.