Deck 7: Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building

Question 1

Under which of the following conditions would a body of rock be more likely to exhibit plastic behavior?

A)low temperature
B)high temperature
C)low pressure
D)high rate of deformation

Answer 1

B

Question 2

A body of rock affected by compression will likely undergo

A)shortening.
B)stretching.
C)shear strain
D)rotation.

Answer 2

A

Question 3

What kind of stress results in the lengthening of rock?

A)compressional
B)tensional
C)shear
D)brittle

Answer 3

D

Question 4

Under which condition would a body of rock be most likely to exhibit brittle behavior?

A)slow rate of deformation
B)low temperature
C)high temperature
D)high pressure

Question 5

Normal, reverse, and thrust are all examples of _________ faults.

A)strike-slip
B)dip-slip
C)oblique-slip
D)lateral

Question 6

Which of the following occurs when rocks bend, break, or flow during mountain building?

A)deformation
B)orogeny
C)lengthening
D)stress

Question 7

The formation of joints in a rock in response to tension is an example of

A)brittle deformation.
B)plastic deformation.
C)shear strain.
D)rotation.

Question 8

Which of the following occurs when rocks are pulled apart?

A)compression
B)tension
C)shear
D)pressure

Question 9

Right-lateral and left-lateral are both examples of _________ faults.

A)strike-slip
B)dip-slip
C)oblique-slip
D)reverse

Question 10

A body of rock affected by tension will likely undergo

A)shortening.
B)stretching.
C)shear strain
D)rotation.

Question 11

Which type of situation would be more likely to produce folds?

A)cold, brittle crust under tension
B)cold, brittle crust under compression
C)warm, ductile crust under tension
D)warm, ductile crust under compression

Question 12

Folds are most often associated with _________ stress.

A)tensional
B)compressional
C)shear
D)straight

Question 13

A fold shaped like an elongated arch is a(n)

A)anticline.
B)basin.
C)dome.
D)syncline

Question 14

Force-per-unit area is termed

A) stress.
B) strain.
C) power.
D) work.

Question 15

Which of the following is a change in the shape of a rock induced by stress?

A)Elastic rebound
B)Pressure release
C)Strain
D)Metamorphosis

Question 16

How is stress different from strain?

A)Strain is a measure of the offset on a fault as a result of applied stress.
B)Stress is the change in shape of a rock as a result of applied strain.
C)Strain is the change in shape of a rock as a result of applied stress.
D)They are not different; stress and strain are synonymous.

Question 17

Tectonic foliation is most likely to occur as a result of

A)metamorphism.
B)faulting.
C)brittle deformation.
D)rotation.

Question 18

How does the rate at which a body of rock is deformed affect its behavior?

A)A rock deformed quickly is likely to exhibit brittle behavior.
B)A rock deformed slowly is likely to exhibit brittle behavior.
C)The rate of deformation has no effect on a rock's behavior.
D)The rate of deformation is important only below the brittle/plastic transition.

Question 19

The fossil in the image below has been subjected to what type of stress?

A)brittle
B)tensional
C)shear
D)compressional

Question 20

Normal faults are generally the result of _________ stress.

A)tensional
B)compressional
C)shear
D)triaxial

Question 21

Normal faulting is most often associated with mountain building along ___________ boundaries, whereas reverse faulting is generally observed at ___________ boundaries.

A) divergent; transform
B) transform; convergent
C)convergent; divergent
D)divergent; convergent

Question 22

An episode of mountain building is termed a(n)

A)orogeny.
B)phylogeny.
C)aureole.
D)slickenside.

Question 23

Mountains forming would be most likely found at the

A)eastern South American plate boundary.
B)western South American plate boundary.
C)eastern South American continental margin.
D)center of the South American continent.

Question 24

Regularly spaced joints in an outcrop may indicate that an area

A)is under intense shear stress.
B)has experienced compressional stress.
C)is underlain by a thrust fault.
D)is formed from rocks that were once at great depth.

Question 25

In the following map, the vertical, north-south trending fault is a ________ fault.

A)normal dip-slip
B)reverse dip-slip
C)right-lateral strike-slip
D)left-lateral strike-slip

Question 26

On a geologic map, if the contacts between sedimentary rock units form a series of parallel lines, with the youngest unit in the center, the underlying structure is a

A)horizontal anticline.
B)plunging anticline.
C)non-plunging syncline.
D)plunging syncline.

Question 27

The Himalayan mountain range was formed at which tectonic setting?

A)a convergent plate boundary
B)a divergent plate boundary
C)a transform plate boundary
D)hotspots

Question 28

During the formation of Pangea, Africa collided with North America and created the Appalachian Mountains. Which of the following mountain ranges is a modern analogue to the ancient Appalachian Mountains?

A)Andes Mountains
B)Sierra Nevada Mountains
C)Italian Alps
D)Cascade Mountains

Question 29

The formation of the Basin and Range Province, a fault-blocked mountain range in Utah, Nevada, and Arizona, is associated with which of the following processes?

A)continental rifting
B)continental collision
C)fold and thrust faulting
D)subduction zone volcanism

Question 30

The distinction between joints and faults is that

A)faults are joints that are greater than 1 square meter in areal extent.
B)faults are fractures along which displacement has occurred; displacement does not occur along joints.
C)joints are fractures along which displacement has occurred; displacement does not occur along faults.
D)There is no distinction; the two terms are synonymous.

Question 31

The fold in the image below is a(n)

A)anticline.
B)basin.
C)dome.
D)syncline

Question 32

Which of the following faults could result from both strike-slip and dip-slip stresses?

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

Question 33

Mountain ranges formed along subduction zones are formed, in part, by ___________ in the crust.

A)compression
B)stretching
C)extension
D)elongation

Question 34

The balance between the weight of a mountain range and the buoyancy provided by the underlying mantle is termed

A) delamination.
B) suture.
C)isostasy.
D)orogen.

Question 35

As the mountains in a mountain range are slowly eroded, the crustal root

A)is eroded at the same rate.
B)remains stationary.
C)sinks deeper into the mantle.
D)rises out of the mantle.

Question 36

Regions where Precambrian metamorphic rocks are exposed at the surface are termed

A)shields.
B)cratonic platforms.
C)convergent margins.
D)domes.

Question 37

Continental crust is typically 35 km thick but may be up to __________ thick under mountain ranges.

A)40 km
B)70 km
C)200
D)400

Question 38

The outer portion of a craton, where deformed rocks are covered by sediments, is termed the

A)shield.
B)cratonic platform.
C)convergent margin.
D)exotic terrane.

Question 39

Which of the following is the process whereby rocks from depth are exposed at the surface during mountain building?

A) subsidence
B) uplift
C)jointing
D)foliation

Question 40

Which of these properly illustrates the principle of isostasy?

A)High-density crust floats on top of low-density mantle.
B)Mountains stand high because they are gravitationally balanced by their deep crustal roots.
C)When weight is added to the crust, the crust responds by rebounding upward.
D)When material is removed from the crust, the crust maintains the new, lower elevation.

Question 41

What can be said about a mountain range that is being uplifted at 2 cm/yr but is not growing any taller?

A)The crustal root is thinning at the same rate as the uplift.
B)The crustal root is thickening faster than the uplift.
C)The rate of erosion is the same as the rate of uplift.
D)The rate of erosion is higher than the rate of uplift.

Question 42

The Appalachian Mountains were formed as a result of the collision of North America and Africa at the end of the Paleozoic era. Describe what the Appalachians looked like when formed and what has caused them to become a series of gently sloping hills today.

Question 43

Which of the following shows a thrust fault?

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

Question 44

Metamorphic rocks found in cratons are exposed during orogenesis by

A)faulting.
B)folding.
C)shields.
D)erosion.

Question 45

Describe the differences between brittle and ductile deformation.

Question 46

What is the ultimate fate of all mountains on Earth?

Question 47

How were the mountains in the Basin and Range Province formed?

Question 48

What is the difference between a dip-slip fault and a strike slip fault? Provide examples of each.

Question 49

Draw a cross section of a normal and reverse fault. For each, list the stress involved and changes in the length of the crust, if any.

Question 50

What are the three components of deformation? Briefly explain each.

Question 51

Mount Marshak towers above the landscape at 5.3 km tall. The rate of uplift at Mount Marshak is 1.3 mm/yr and the rate of erosion is 1.5 mm/yr. How tall will Mount Marshak be after a million years, assuming everything remains constant?

A)5.5 km
B)7.3 km
C)5.1 km
D)3.3 km

Question 52

What types of geologic structures would you expect to find in an area that had undergone compression?

Question 53

Compare and contrast domes and basins. If both are composed solely of sedimentary beds that have been eroded such that the ground surface is level, how would you identify each?

Question 54

What do strike and dip describe?

A)orientation of planar features
B)degree of metamorphism
C)depth of faulting
D)location of a structure

Question 55

Which of the following shows a plunging fold?

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

Question 56

Which picture illustrates a likely outcome of compression in the crust?

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

Question 57

What are joints? What might the presence of joints in a rock indicate?

Question 58

Regions of continents that have NOT been subjected to mountain-building events during the past 1 billion years are termed

A)exotic terranes.
B)accreted terranes.
C)cratons.
D)cratonic platforms.

Question 59

Erosional processes work to remove material from mountains; thus, over time the topography will become less

A)rugged.
B)weathered.
C)flat-lying
D)stretched.