Question 1

Which of the following changes in conditions represents decompression melting?

Accepted Answer

A)   from A to B
B)   from B to A
C)   from B to C
D)   from C to B
E)   from D to AF) A) and D)
G) D) and E)

Question 2

What texture is displayed by the igneous rock in this photograph?

Accepted Answer

A)   vesicles
B)   breccia
C)   porphyritic
D)   glassy
E)   none of theseF) C) and E)
G) None of the above

Question 3

Which of the magma systems shown is most likely to include felsic or intermediate magmas?

Accepted Answer

A)   A and B
B)   B and C
C)   A, B, and C
D)   B, C, and D
E)   C, D, and EF) B) and C)
G) A) and C)

Question 4

The igneous feature shown in this figure is a:

Accepted Answer

A)   dike
B)   sill
C)   volcanic neck
D)   laccolithE) A) and D)
F) B) and D)

Question 5

What is a path for magma as it solidifies at great depth and then is uplifted slowly toward the surface?

Accepted Answer

A)   from B to A
B)   from C to A
C)   from C to B to A
D)   from D to C to B
E)   from D to C to AF) A) and D)
G) A) and C)

Question 6

When melting forms magma:

Accepted Answer

A)   rocks in the source region generally are completely melted
B)   partial melting produces a magma that is more felsic than the source
C)   melting of the mantle generally produces felsic magma
D)   melting of continental crust generally produces mafic magma
E)   none of theseF) C) and E)
G) B) and E)

Question 7

What texture is displayed by the igneous rock in this photograph?

Accepted Answer

A)   vesicles
B)   breccia
C)   porphyritic
D)   glassy
E)   none of theseF) B) and E)
G) A) and E)

Question 8

How could a rock at point C be melted?

Accepted Answer

A)   increase in temperature
B)   decrease in pressure
C)   increase in temperature accompanied by a decrease in pressure
D)   all of theseE) B) and D)
F) C) and D)

Question 9

Most subduction-derived magma never reaches the surface. However, what is formed if this type of magma reaches the surface of a continent?

Accepted Answer

A)   belts of volcanoes
B)   lines of calderas
C)   basalt fissureD) None of the above
E) A) and B)

Question 10

Which of the following is the best example of heat transfer by conduction?

Accepted Answer

A)   newly created lithosphere loses heat to adjacent rocks
B)   water flows in a circular path in a pan
C)   a burner gives heat through the air without touching the object
D)   seawater is drawn into a mid-ocean ridgeE) C) and D)
F) B) and C)

Question 11

Which of the following photographs depicts an igneous rock where the magma cooled slowly at first and then had fast cooling?

Accepted Answer

A)   
B)   
C)   
D)   E) B) and D)
F) All of the above D

Question 12

Most hot spots are considered to be:

Accepted Answer

A)   crustal expressions of a rising plume of hot magma
B)   volcanoes with an active lava flow
C)   seamounts with no active flow of lavaD) All of the above
E) B) and C)

Question 13

Which letter in this classification table indicates the position of gabbro?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   EF) B) and D)
G) A) and D)

Question 14

What does this welded texture indicate about the formation of this rock?

Accepted Answer

A)   It formed from an explosive pyroclastic eruption.
B)   The rock solidified at great depth.
C)   The magma formed some crystals before rising closer to the surface and solidifying.
D)   The magma had abundant dissolved gas.E) A) and C)
F) All of the above A

Question 15

An igneous rock that solidifies below the surface is called an) :

Accepted Answer

A)   intrusive rock
B)   extrusive rock
C)   magma rock
D)   lava rockE) B) and C)
F) A) and B)

Question 16

An ophiolite is identical to:

Accepted Answer

A)   a newly formed segment of oceanic crust, except it contains an additional layer of sediment
B)   a magma chamber, only it is formed beneath the ocean
C)   a combination of mafic and felsic magmas at depth lodged within sheeted dikes of basaltD) All of the above
E) A) and B)

Question 17

For the letters on this figure, choose the likely cause of melting for Site B.

Accepted Answer

A)   Decompression melting as the mantle rises
B)   Melting by adding water
C)   Melting of continental crust caused by an influx of mantle-derived magmasD) A) and B)
E) All of the above

Question 18

What does the texture of this rock indicate about its cooling history? The magma cooled:

Accepted Answer

A)   entirely at the surface
B)   for a while at some depth and then rose to the surface where it finished solidifying
C)   slowly under relatively deep conditions
D)   slowly in the presence of waterE) A) and B)
F) All of the above

Question 19

Which of the following igneous rocks would be formed by the fastest cooling?

Accepted Answer

A)   very coarse granite pegmatite
B)   coarse granite
C)   medium-grained granite
D)   fine-grained granite
E)   volcanic glassF) A) and B)
G) None of the above

Question 20

At which of the sites shown in this figure would melting probably be caused by introduction of water into hot rocks?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   EF) All of the above
G) C) and E) C

Exam 5: Igneous Environments

Which of the following changes in conditions represents decompression melting?

Correct AnswerverifiedShow Answer

What texture is displayed by the igneous rock in this photograph?

Correct AnswerverifiedShow Answer

Which of the magma systems shown is most likely to include felsic or intermediate magmas?

Correct AnswerverifiedShow Answer

The igneous feature shown in this figure is a:

Correct AnswerverifiedShow Answer

What is a path for magma as it solidifies at great depth and then is uplifted slowly toward the surface?

Correct AnswerverifiedShow Answer

When melting forms magma:

Correct AnswerverifiedShow Answer

What texture is displayed by the igneous rock in this photograph?

Correct AnswerverifiedShow Answer

How could a rock at point C be melted?

Correct AnswerverifiedShow Answer

Most subduction-derived magma never reaches the surface. However, what is formed if this type of magma reaches the surface of a continent?

Correct AnswerverifiedShow Answer

Which of the following is the best example of heat transfer by conduction?

Correct AnswerverifiedShow Answer

Which of the following photographs depicts an igneous rock where the magma cooled slowly at first and then had fast cooling?

Correct AnswerverifiedD

Most hot spots are considered to be:

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Which letter in this classification table indicates the position of gabbro?

Correct AnswerverifiedShow Answer

What does this welded texture indicate about the formation of this rock?

Correct AnswerverifiedA

An igneous rock that solidifies below the surface is called an) :

Correct AnswerverifiedShow Answer

An ophiolite is identical to:

Correct AnswerverifiedShow Answer

For the letters on this figure, choose the likely cause of melting for Site B.

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What does the texture of this rock indicate about its cooling history? The magma cooled:

Correct AnswerverifiedShow Answer

Which of the following igneous rocks would be formed by the fastest cooling?

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At which of the sites shown in this figure would melting probably be caused by introduction of water into hot rocks?

Correct AnswerverifiedC

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D

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A

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C