Deck 13: Deformation, Mountain Building, and the Evolution of Continents

Question 1

Most mountain belts are the result complex deformation by compression.

Answer 1

True

Question 2

The Appalachian Mountains are the result of deformation along a convergent plate boundary.

Answer 2

True

Question 3

Local geologic structures can be ignored in site selection for large structures because they formed so long ago.

Answer 3

False

Question 4

Stress is the force that causes strain.

Question 5

Strain is deformation caused by stress.

Question 6

Stress is the result of an applied strain.

Question 7

Rock layers subjected to tension are commonly shortened in the direction of stress by either faulting or folding.

Question 8

Elastic strain can result from compression, tension, or shear.

Question 9

Stratified rocks which are not horizontal in exposure are exceptions to the principle of superposition.

Question 10

The youngest exposed rocks are found in the center of a structural basin.

Question 11

An anticline is the result of plastic strain associated with compressional stress.

Question 12

Folding of rocks require that the rock behave in an elastic manner during the actual folding.

Question 13

The strike of rocks along the flank of an syncline would normally parallel the axis of the syncline.

Question 14

Normal faulting would result from compressional stress.

Question 15

Tensional stresses produce mountains through folding.

Question 16

In North America, accreted terranes have been identified only in the North American Pacific northwest.

Question 17

The Canadian Shield has rugged topography due to the great age of the craton rocks.

Question 18

Plate boundary type (e.g. convergent) is constant over time along a given plate margin.

Question 19

Rocks deform in response to

A) compressional stresses
B) tensional stresses
C) shear stresses
D) A and B
E) all of the above

Question 20

Rocks exposed to compressional stress are

A) squeezed by external forces directed toward one another
B) shortened in the direction of stress
C) faulted or folded
D) all of the above

Question 21

Rocks strained beyond their elastic limit by compressional stresses will result in

A) folding
B) normal faulting
C) shearing
D) volcanism
E) isostatic rebound

Question 22

Rocks that exhibit the effects of plastic deformation

A) must have originated along a divergent plate boundary
B) must have been subjected to compressional stress
C) must have occurred deep within the crust
D) must have been associated with intrusive activity
E) A and D

Question 23

Plastic deformation would most likely be associated with

A) igneous rocks
B) sedimentary rocks
C) metamorphic rocks
D) A and C
E) B and C

Question 24

Monoclines are the result of

A) compressional stress from one direction only
B) deep subsurface faulting that does not extend to the surface
C) tensional stress accompanying plastic deformation
D) folds with low amplitude and long wavelength

Question 25

Geologic structures found in mountain ranges formed by compression at convergent plate margins would likely include

A) overturned and recumbent folds
B) plunging folds
C) reverse faulting
D) A and B
E) all of the above

Question 26

County officials associated with emergency planning and management should be most concerned with

A) faults
B) joints
C) folds
D) all of the above

Question 27

For a normal fault to occur, which of the following sets of conditions would have to be present?

A) compressional stress and brittle fracture
B) compressional stress and plastic strain
C) tensional stress and brittle fracture
D) tensional stress and elastic strain
E) tensional stress and plastic strain

Question 28

For a fold to occur, which of the following sets of conditions would have to be present?

A) compressional stress and brittle fracture
B) compressional stress and plastic strain
C) tensional stress and brittle fracture
D) tensional stress and elastic strain
E) tensional stress and plastic strain

Question 29

Oceanic-continental plate orogenesis can be recognized in the geological record by

A) an accretionary wedge containing ophiolites.
B) a landward belt of volcanoes and batholiths.
C) an inland zone of block faults.
D) A and B
E) all of the above

Question 30

Accreted terranes identified on the west coast of North America have been accreted within the past

A) 200 million years.
B) 100 million years.
C) 20 million years.
D) 10 million years.
E) 2 million years.

Question 31

Terranes are believed to have originated

A) by processes not presently understood.
B) by collision with asteroids.
C) from great distances and distant plates but within the same hemisphere.
D) from great distances including opposite hemispheres.
E) all of the above

Question 32

A rock that behaves as a brittle solid near the surface may behave in a ductile manner and deform ___________when under higher ___________and pressures, and thus will___________ instead of fracture.

Question 33

A rock that behaves as a brittle solid and undergoes compressional stress would result in a_____________fault.

Question 34

A rock that behaves as a brittle solid and undergoes tensional stress would result in a___________ fault.

Question 35

Anticlines and synclines differ from domes and basins, in that the latter are more___________in shape than the former.

Question 36

The___________ is an imaginary sea level surface extending continuously through the continents.

Question 37

___________is the force applied to a given area, and___________ is the deformation caused by stress which exceeds internal strength.

Question 38

___________ rocks show little or no plastic strain before fracture, while___________rocks show much plastic strain.

Question 39

A ___________is a type of fold which has axial beds that are younger than those of its limbs and limbs which dip toward its axis?

Question 40

Describe the type of stress and expected structures associated with each type of plate tectonic boundary.

Question 41

Why is some knowledge of stress-strain relationships and rock behavior significant to the general public? Use an example in your explanation.

Question 42

What are three possible uses for geologic maps?

Question 43

Briefly explain the three-stage scenario by which the cratons of continents evolved.

Question 44

Compare and contrast the Appalachian Mountains with the Andes Mountains relative to their age and plate tectonic setting.

Question 45

Why are some rock units folded and others of similar rock type faulted?

Question 46

What plate tectonic setting is responsible for the large mountain systems of the world?

Question 47

What happens if a rock undergoes an elastic strain?

Question 48

What is the strike of an inclined rock layer?

Question 49

What type of fold is an up-arched fold?

Question 50

What can we say about a fold if both its limbs dip in the same direction?

Question 51

When is a fold described as being asymmetrical?

Question 52

How are non-plunging synclines distinguished from anticlines on geologic maps?

Question 53

What is a fault scarp?

Question 54

What are two types of dip-slip faults?

Question 55

Which type of fault is one in which the hanging wall has moved downward relative to the foot wall?

Question 56

What type of faults are caused by shearing forces ?

Question 57

What are two types of strike-slip faults?

Question 58

What is the difference between an anticline and a monocline?

Question 59

What kind of fault is the infamous San Andreas Fault in California?

Question 60

What kind of movement has there been along the San Andreas Fault (i.e., which side has been moving in which relative direction)?

Question 61

How is a fault classified when it has components of both dip-slip and strike-slip movement?

Question 62

What kind of information can a geologic map be used to present?

Question 63

What is the difference between horsts and grabens?

Question 64

What type of forces produce block faulted mountains such as those in the Basin and Range Province of the southwestern United States?

Question 65

Name the two zones (belts) in which most of Earth's geologically recent and present-day orogenic activity is concentrated.

Question 66

Which of the three major types of plate boundaries is responsible for most orogenesis?

Question 67

Volcanic island arcs are characteristic of which type of convergent plate boundaries?

Question 68

Give an example of a mountain range formed as a result of continental-continental plate collision.

Question 69

What are three ways in which terranes differ from surrounding strata and can therefore be identified?

Question 70

What is the age of the oldest known rocks that have been dated?

Question 71

In what country were these oldest dated rocks recently discovered?

Question 72

What is a shield, such as the Canadian Shield?

Question 73

What is the difference between a shield and a craton?

Question 74

Along which margins of the North American craton have orogeny and accretion occurred mainly during the last 570 million years, to give North America its present shape?

Question 75

During which Era did the rocks of the Appalachian and Ouachita Mountains form?

Question 76

How long ago did the Laramide orogeny begin?

Question 77

What is the name of the complex mountainous region which extends through North America from Alaska into central Mexico?

Question 78

The Colorado Plateau, Rocky Mountains, Columbia Plateau, Sierra Madre Occidental, and Sierra Nevada are all elements of what major mountainous complex in North America?