Deck 10: Crustal Deformation and Mountain Building

Question 1

A(n)________ fault has little or no vertical movements of the two blocks.

A)stick slip
B)oblique slip
C)strike slip
D)dip slip

Answer 1

C

Question 2

The San Andreas Fault in California and the Alpine Fault in New Zealand are examples of ________.

A)normal faults
B)thrust faults
C)strike-slip faults
D)oblique-slip normal faults

Answer 2

C

Question 3

In the figure,which of the deformations appears most similar to what might be expected along a divergent plate boundary?

A)original
B)X
C)Y
D)Z

Answer 3

C

Question 4

In the figure,which of the deformations appears most similar to what might be expected along a transform plate boundary?

A)original
B)X
C)Y
D)Z

Question 5

You are walking north across dipping beds in sedimentary rocks.You walk across 200m of rocks with a relatively constant dip of 20 degrees to the south.Suddenly you come to beds with lower dip that become flat lying,and then dip north across a horizontal distance of only about 30m.As you walk on the beds become more steeply dipping until they dip almost 80 degrees to the north.You walk across these steeply dipping beds for 40m,and then beds return to a south dip of about 20 degrees.What kind of structure(s)did you just walk across? (A sketch may help you solve this problem.)

A)a symmetric anticline
B)an asymmetric syncline
C)an asymmetric anticline and syncline
D)an asymmetric anticline
E)a symmetric syncline

Question 6

In the figure,the stress on block 'X' is ________.

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

Question 7

A transform fault is ________.

A)a strike-slip fault that forms the boundary between tectonic plates
B)a dip-slip fault connecting an anticline with a syncline
C)a reverse fault that steepens into a thrust fault
D)the rift bounding fault on a mid-ocean ridge

Question 8

The material in the figure was ________ when the folding occurred.

A)ductile
B)elastic
C)brittle
D)strong

Question 9

The concepts of "stress" and "strain" are related because ________.

A)"strain" causes "stress"
B)"stress" causes "strain"
C)compressional "stress" causes a convergent plate boundary to form
D)compressional "strain" causes a convergent plate boundary to form

Question 10

In the figure,the stress on block 'Y' is ________.

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

Question 11

Folds are an example of ________.

A)brittle deformation
B)ductile deformation
C)elastic deformation
D)shear deformation

Question 12

Large circular downwarped structures are called ________.

A)anticlines
B)synclines
C)basins
D)domes

Question 13

Most active faults pose a risk to society because they can potentially produce ________.

A)landslides
B)tsunamis
C)earthquakes
D)disruptions in groundwater flow

Question 14

Monoclines,anticlines,synclines and domes are all examples of ________.

A)faulting
B)jointing
C)flow
D)foliation

Question 15

In the figure,the stress on block 'Z' is ________.

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

Question 16

Burial of rocks increases the confining pressure so that deeply buried rocks are more likely to ________ than shallow rocks.

A)fracture
B)fold
C)deform
D)shear

Question 17

In a monocline,one of the limbs of the fold ________.

A)is horizontal
B)is vertical
C)dips in the same direction as the other limb,but at a lower angle
D)has a shallower dip in the opposite direction of the other limb

Question 18

The higher the temperature,the more likely it is that a rock will deform ________.

A)ductilely
B)brittlely
C)elastically
D)shearingly

Question 19

When subjected to a differential stress,a very "brittle" material,like glass,will ________.

A)not bend at all.It will only break.
B)deform by breaking or elastic bending
C)flow or shear if the stress is large enough
D)flow under low to moderate stress conditions

Question 20

In an overturned fold,the beds have rotated ________.

A)more than 180 degrees
B)more than 90 degrees
C)more than 45 degrees
D)100 to 150 degrees

Question 21

Grabens are formed by what type of faulting?

A)normal
B)reverse
C)strike-slip
D)collision

Question 22

You are walking on the beach along the south-coast of Alaska.You see rocks cut by numerous faults that consist of basalt with evidence of eruption in the ocean,deep-water chert,mudstone,and sandstones with abundant volcanic material.What tectonic setting would you assign to these rocks?

A)passive continental margin sequence
B)forearc basin
C)continental interior basin
D)accretionary wedge

Question 23

Use this figure for the following questions: The figure above is an oblique Google earth image from southwestern North America looking approximately north.The view is approximately 50km across.The area is a classic area of normal faulting.
The area labeled C shows an active fault bounding the range.Which best describes the motion on the fault?

A)west side up
B)east side up
C)north side down
D)south side down
E)right lateral strike-slip

Question 24

In a(n)________ fault,the hanging wall block moves up with respect to the footwall block.

A)normal
B)strike slip
C)reverse
D)abnormal

Question 25

Most granitic batholiths represent ________.

A)a deeply exhumed passive continental margin
B)a deeply exhumed forearc rock assemblage
C)magmas generated in a rift system,prior to development of a passive margin
D)the exhumed roots of a subduction related magmatic arc

Question 26

A good example of a present-day,passive continental margin is the ________.

A)north flank of the East Pacific Rise
B)west coast of South America
C)east coast of the Japanese Islands
D)east coast of North America

Question 27

In thrust faulting,________.

A)grabens develop on the footwall block
B)the crust is shortened and thickened
C)horizontal,tensional stresses drive the deformation
D)the hanging wall block slips downward along the thrust fault

Question 28

Granitic batholiths typically form over time intervals of ________.

A)tens of thousands of years
B)hundreds of thousands of years
C)millions of years
D)billions of years

Question 29

The Peninsular terrane is now part of the crust of North America in southern Alaska.The dominant rock type in this terrane is intrusive igneous rock that ranges in composition from gabbro to granite and volcanic rock with a similar compositional range.Geologic evidence indicates the Peninsular terrane collided with North America during late Mesozoic time.Which of the following would be the most reasonable interpretation for the origins of the Peninsular terrane?

A)a Mesozoic island arc
B)a Mesozoic oceanic plateau
C)a Mesozoic accretionary wedge
D)a Cenozoic forearc basin
E)a Paleozoic accretionary wedge

Question 30

Use this figure for the following questions: The figure above is an oblique Google earth image from southwestern North America looking approximately north.The view is approximately 50km across.The area is a classic area of normal faulting.
This area represents what type of mountain system

A)Fault block mountains
B)Andrean type mountains
C)Collisional orogen
D)Strike-slip mountains

Question 31

Southwestern North America contains a large area called the Basin and Range province.What is the origin of this name?

A)Ranges are uplifted horst blocks adjacent to basins formed as graben.
B)The area is characterized by chains of volcanos forming ranges next to basins that form valleys.
C)Thrust faulting along the San Andreas fault produces linear ridges,the ranges,with intervening basinal valleys forming fault block mountains.
D)Folds have formed by compressional stresses along the plate margin forming ridges (ranges)and valleys (the basins)of the basin and range province.

Question 32

What type of basin would be most likely to contain large amounts of sediments derived from a volcanic source?

A)a continental interior basin
B)a passive continental margin
C)a forearc basin
D)a strike-slip basin

Question 33

A(n)________ is a thick accumulation of sediments and small tectonic blocks formed of material scraped off subducting oceanic lithosphere at a convergent margin.

A)mass movement complex
B)continental shelf,terrain complex
C)accretionary-wedge complex
D)subterranean-accumulation complex

Question 34

Studies of the chemistry of rocks from arc volcanos indicate the main source of the magma is ________.

A)melting of subducted oceanic crust
B)melting of the subducted mantle lithosphere
C)melting of the asthenosphere above the subducting oceanic plate by frictional heating on the subduction interface
D)melting of the asthenosphere above the subducting oceanic plate by fluids acting as a flux to enhance melting

Question 35

What is the modern theory for orogenesis?

A)geosynclinal theory
B)shrinking earth model
C)expanding earth theory
D)plate tectonics theory

Question 36

In what part of a subduction margin might you find rocks deposited on the abyssal plain,far from land?

A)Accretionary Wedge
B)Volcanic Arc
C)Forearc Basin
D)Cratonic Basin

Question 37

Island arcs and Andean type mountains are both examples of mountains formed by ________.

A)collisional tectonics
B)subduction
C)rifting/oceanic spreading
D)transform faults

Question 38

The west coast of California is underlain by rocks that represent ________.

A)an ancient volcanic arc
B)an ancient Forearc Basin and accretionary wedge
C)a collisional orogenic belt
D)an oceanic plateau

Question 39

The Sierra Nevada Mountains of California,and the Teton Mountains of Wyoming,ranges are examples of ________.

A)fault blocks uplifted by late Tertiary to Quaternary normal faulting
B)folding,compression,and thickening of Paleozoic strata in Jurassic time
C)isostatic uplift of crust over thickened in early Paleozoic time
D)uplifted blocks bounded by Quaternary reverse faults

Question 40

Mountain building uplifts rocks against the force of gravity raising their potential energy,which requires work by the earth system.Based on the relative motion of fault blocks,what type of fault would you expect to require more energy than the others?

A)normal
B)strike-slip
C)thrust
D)There is no way of knowing.

Question 41

The Rocky Mountains of western North America were produced in an orogeny called the ________.

A)Absaroka orogeny
B)Laurentide orogeny
C)Uinta orogeny
D)Laramide orogeny

Question 42

Island arc systems now on the Tibet plateau record subduction prior to the collision of India with Eurasia.Geologists would map these pre-collisional arc rocks as ________.

A)hot spot tracks
B)terranes
C)rift zones
D)pre-collisional transform zones

Question 43

When the differential stress exceeds the strength of the material,the material will begin to undergo elastic strain.

Question 44

In the interior of continents the earth's crust is typically about 40km thick and the elevation is near sea level.In an area where the crust is 20km thick,isostasy would suggest the elevation in this area would be ________ unless the density changes from one area to the other.

A)below sea level
B)near sea level
C)slightly above sea level
D)high mountains

Question 45

The ________ is (are)characterized by terrane accretion that has been active throughout most of Mesozoic and Cenozoic time.

A)western margin of Africa
B)southern margins of India and Australia
C)western margin of North America
D)western margin of the Mid-Atlantic Ridge

Question 46

Ocean spreading centers are highlands on the ocean floor,sometimes referred to as submarine mountains.Oceanic crust worldwide is about the same thickness so isostasy would suggest the ocean floor should be as flat as Kansas.Which of the following statements best describes the origin of these submarine mountains?

A)The ridges are sites of young volcanos that produce high topography on the sea floor,like Hawaii.
B)The ridges represent upwelling zones from the core which produces a bulge at the earth's surface.
C)Compression at the ridges produce local uplift along the ridge axis.
D)The mantle beneath the ridges remains hot for millions of years producing an elevated region along the ridge axis because hot rocks are lower density than cold rocks.

Question 47

Refer to the figure below,captured from Google Earth,for the following questions.
This mountain belt would be called ________.

A)a collisional mountain belt
B)a terrane accretion mountain belt
C)an Andrean mountain belt
D)fault block mountains

Question 48

Folded limestones that are exposed high elevations in the Himalayas were originally deposited as sediments in a ________.

A)marine basin between India and Eurasia.
B)Cenozoic fault basin between Africa and Arabia.
C)deep ocean trench along the southern margin of India.
D)late Paleozoic syncline north of the Tibetan Plateau.

Question 49

A widely cited theory associates active faults and earthquakes in China and southeast Asia to the India-Eurasia collision.This theory suggests ________.

A)East Asia is moving toward the Himalaya,causing faulting and earthquakes
B)subduction beneath East Asia is pushing East Asia toward the Himalaya,forming young mountains between the Himalaya and Pacific subduction zones
C)India is moving west relative to Eurasia,pulling central Asia away from East Asia
D)India is plowing into the "soft underbelly" of Asia,pushing East Asia eastward

Question 50

The Appalachian Mountains may have once been as lofty as the Himalayan-Tibetan Mountain belt is today.Why are they not this high now?

A)They developed a dense crustal root following collision,and isostasy forced them to sink to their present elevation.
B)They formed long ago,and erosion has beveled them to their present low elevation.
C)The mountains cooled following the collision,which increased the density of the of the rocks by cooling,and isostasy forced the mountains to sink.
D)Opening of the North Atlantic Ocean converted lithosphere to asthenosphere beneath eastern North America,forcing eastern North America to sink to low elevations.

Question 51

A thrust fault increases the thickness of the crust as it moves toward a continental interior in a mountain belt; yet the crust beyond the mountain front stays the same thickness.Isostasy would suggest that the area at the mountain front,where the thrust emerges,should ________ over time.

A)uplift
B)stay the same
C)subside
D)near sea level

Question 52

In the interior of continents the earth's crust is typically about 40km thick and the elevation is near sea level.Most earth materials expand when heated,lowering their density.During rifting continental margins are heated but cool as sea floor spreading moves offshore from the continent.Thus,basic isostasy suggests that after rifting,a continental margin will ________.

A)uplift
B)subside
C)remain near sea level
D)rise slowly as erosion removes uplifted rocks

Question 53

The Appalachians were formed by three phases of ________ orogeny.

A)collisional
B)Andean
C)rifting
D)transform

Question 54

Orogenesis refers to the formation of mineral deposits.

Question 55

The Tibetan plateau is high above sea level because ________.

A)there are many active faults across Tibet that produce internal crustal thickening and uplift
B)the extrusion of East Asia has produced structures that thicken the crust under Tibet,producing regional uplift
C)a giant fault beneath Tibet raises it up relative to adjacent areas
D)crustal thickening over millions of years has produced a thick crust that stands high due to Isostasy

Question 56

The Himalayas and Tibet are the archetypical example of a(n)________ mountain belt.

A)Andean
B)continental rift
C)transform
D)collisional

Question 57

Most geologists think the elevation of mountains above sea level is limited by earth's gravity because ________.

A)rocks can never reach escape velocity
B)rock cliffs are subject to gravity failure and can only be about 1km high
C)the earth's mantle is too weak to support the load of large mountains
D)thickening of the crust in mountain belts produces a weak deep crust the spreads by gravity collapse,limiting the elevation

Question 58

Mountain building in the western margin of North America records a history of both ________.

A)continental collision and terrane accretion
B)Andean type subduction and terrane accretion
C)Andean type subduction and continental collision
D)none of the above

Question 59

The hinge of a fold must lie within the axial plane of the fold.

Question 60

The boundary between two terranes or two continents that have collided is called a ________.

A)suture
B)join
C)weld
D)stitch

Question 61

Fractures in rock with no conspicuous offset are called ________.

Question 62

________

Question 63

Exhumed basins contain ________ rocks in the center of the structure and domes contain ________ rocks in the center.

Question 64

Changes in the shape of a rock body in response to a differential stress is called ________.

Question 65

A(n)________ fault forms when the hanging wall moves down relative to the footwall .

Question 66

Terrane accretion generally occurs along a divergent boundary between a continental plate and an oceanic plate.

Question 67

Use this figure for the following questions: The figure above is an oblique Google earth image from southwestern North America looking approximately north.The view is approximately 50km across.The area is a classic area of normal faulting.
The topographic highlands,or ranges,in this area labeled A are also called ________ blocks.

Question 68

________

Question 69

What type of structure is shown below?

Question 70

When the hinge line of a fold is not horizontal the fold is said to ________.

Question 71

Use this figure for the following questions: The figure above is an oblique Google earth image from southwestern North America looking approximately north.The view is approximately 50km across.The area is a classic area of normal faulting.
Topographic basins like the areas labeled B in this figure are called ________.

Question 72

Use this figure for the following questions: The figure above shows a popular area for North American tourists in winter,the Caribbean region.Match the term to the letter on the Figure.
Island arc

Question 73

________

Question 74

On the blanks provided below,fill in the name of the specific type of geologic features that have been labeled.

Question 75

Subduction only occurs when oceanic rocks are forced beneath a continent.

Question 76

Which letter in the figure above corresponds to a "syncline"?

Question 77

Use this figure for the following questions: The figure above shows a popular area for North American tourists in winter,the Caribbean region.Match the term to the letter on the Figure.
Accretionary Wedge

Question 78

Use this figure for the following questions: The figure above shows a popular area for North American tourists in winter,the Caribbean region.Match the term to the letter on the Figure.
Forearc Basin

Question 79

Which letter in the figure corresponds to a "fault"?

Question 80

Subduction produces mountains because subduction zones are the upwelling zones of mantle convection,which lifts the earth's surface to form mountains.