Question 1

Explain how a laccolith is similar to a sill.

Accepted Answer

Both are near-surfac...

Question 2

How does a dike differ from a sill?

Accepted Answer

Dike is tabular (ver...

Question 3

What are the effects of assimilation on magma composition?

Accepted Answer

As magma rises through preexisting rock,...

Question 4

Give one reason why rhyolite flows are less common than basalt flows.

Accepted Answer

Rhyolitic magmas are more visc...

Question 5

What are pegmatites, and how do they form?

Accepted Answer

Pegmatites are composed of mostly felsic...

Question 6

How do volcanic necks form?

Accepted Answer

Magma travels from the magma chamber thr...

Question 7

When looking at a hand sample of an igneous rock, how would you tell if it is plutonic or volcanic?

Accepted Answer

If you can see individual minerals in th...

Question 8

Plutons form within the peaky structure of a volcano.

Accepted Answer

A) True 
 B)False

Question 9

Hot-spot volcanism is likely the result of

Accepted Answer

A)   a subduction zone.
B)   rifting.
C)   strike-slip movements.
D)   a mantle plume.
E)   none of theseF) A) and D)
G) A) and C)

Question 10

What are flood basalts?

Accepted Answer

Flood basalts are va...

Question 11

According to the Bowen's reaction series ____________________ is the first ferromagnesian mineral to crystallize from a mafic magma.

Accepted Answer

The answer of According to the Bowen's reaction series ____________________...

Question 12

What are the three major types of magmas? How are they defined? What elements increase or decrease in the composition of the three types?

Accepted Answer

The three types being felsic or granitic...

Question 13

Most igneous rocks are classified by:

Accepted Answer

A)   texture.
B)   composition.
C)   size.
D)   texture and composition.
E)   composition and size.F) A) and E)
G) A) and D)

Question 14

The presence of ____________________, which are incompletely melted pieces of rock within igneous rocks, demonstrates that ____________________ occurs.

Accepted Answer

inclusions...

Question 15

The only minerals in the continuous branch of Bowen's reaction series are the _________________________.

Accepted Answer

plagioclas...

Question 16

Partial melting of basalt, together with the processes of assimilation, ____________________ settling, and ____________________ mixing, are believed to explain the generation of felsic intrusive magmas from ____________________ magmas.

Accepted Answer

crystal, m...

Question 17

Large crystals found in a fine-grained groundmass can indicate:

Accepted Answer

A)   origin from a magma with an early intrusive phase followed by an extrusive phase.
B)   origin from a magma with an early extrusive phase followed by an intrusive phase.
C)   a rock of mixed volcanic-plutonic origin.
D)   origin from a magma with an early intrusive phase followed by an extrusive phase AND a rock of mixed volcanic-plutonic origin.
E)   origin from a magma with an early extrusive phase followed by an intrusive phase AND a rock of mixed volcanic-plutonic origin.F) D) and E)
G) A) and C)

Question 18

Texture of the rock is influenced by the rate of cooling.

Accepted Answer

A) True 
 B)False

Question 19

Mantle plumes are found primarily at:

Accepted Answer

A)   divergent plate boundaries.
B)   convergent plate boundaries.
C)   transform plate boundaries.
D)   intraplate regions.
E)   none of the aboveF) B) and C)
G) A) and C)

Question 20

What are dikes, sills, and laccoliths?

Accepted Answer

Dikes and sills are tabular or sheet-lik...

Exam 4: Igneous Rocks and Intrusive Igneous Activity

What are flood basalts?

Correct AnswerverifiedFlood basalts are va...View AnswerShow Answer

Give one reason why rhyolite flows are less common than basalt flows.

Correct AnswerverifiedRhyolitic magmas are more visc...View AnswerShow Answer

The presence of ____________________, which are incompletely melted pieces of rock within igneous rocks, demonstrates that ____________________ occurs.

Correct Answerverifiedinclusions...View AnswerShow Answer

What are dikes, sills, and laccoliths?

Correct AnswerverifiedDikes and sills are tabular or sheet-lik...View AnswerShow Answer

How does a dike differ from a sill?

Correct AnswerverifiedDike is tabular (ver...View AnswerShow Answer

Explain how a laccolith is similar to a sill.

Correct AnswerverifiedBoth are near-surfac...View AnswerShow Answer

When looking at a hand sample of an igneous rock, how would you tell if it is plutonic or volcanic?

Correct AnswerverifiedIf you can see individual minerals in th...View AnswerShow Answer

What are pegmatites, and how do they form?

Correct AnswerverifiedPegmatites are composed of mostly felsic...View AnswerShow Answer

Texture of the rock is influenced by the rate of cooling.

Correct AnswerverifiedShow Answer

The only minerals in the continuous branch of Bowen's reaction series are the _________________________.

Correct Answerverifiedplagioclas...View AnswerShow Answer

Mantle plumes are found primarily at:

Correct AnswerverifiedShow Answer

Hot-spot volcanism is likely the result of

Correct AnswerverifiedShow Answer

What are the three major types of magmas? How are they defined? What elements increase or decrease in the composition of the three types?

Correct AnswerverifiedThe three types being felsic or granitic...View AnswerShow Answer

How do volcanic necks form?

Correct AnswerverifiedMagma travels from the magma chamber thr...View AnswerShow Answer

Partial melting of basalt, together with the processes of assimilation, ____________________ settling, and ____________________ mixing, are believed to explain the generation of felsic intrusive magmas from ____________________ magmas.

Correct Answerverifiedcrystal, m...View AnswerShow Answer

What are the effects of assimilation on magma composition?

Correct AnswerverifiedAs magma rises through preexisting rock,...View AnswerShow Answer

Large crystals found in a fine-grained groundmass can indicate:

Correct AnswerverifiedShow Answer

Most igneous rocks are classified by:

Correct AnswerverifiedShow Answer

According to the Bowen's reaction series ____________________ is the first ferromagnesian mineral to crystallize from a mafic magma.

Correct AnswerverifiedShow Answer

Plutons form within the peaky structure of a volcano.

Correct AnswerverifiedShow Answer

Correct Answer
verified
Flood basalts are va...
View Answer

Correct Answer
verified
Rhyolitic magmas are more visc...
View Answer

The presence of , which are incompletely melted pieces of rock within igneous rocks, demonstrates that occurs.

Correct Answer
verified
inclusions...
View Answer

Correct Answer
verified
Dikes and sills are tabular or sheet-lik...
View Answer

Correct Answer
verified
Dike is tabular (ver...
View Answer

Correct Answer
verified
Both are near-surfac...
View Answer

Correct Answer
verified
If you can see individual minerals in th...
View Answer

Correct Answer
verified
Pegmatites are composed of mostly felsic...
View Answer

Correct Answer
verified

Correct Answer
verified
plagioclas...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The three types being felsic or granitic...
View Answer

Correct Answer
verified
Magma travels from the magma chamber thr...
View Answer

Partial melting of basalt, together with the processes of assimilation, settling, and mixing, are believed to explain the generation of felsic intrusive magmas from magmas.

Correct Answer
verified
crystal, m...
View Answer

Correct Answer
verified
As magma rises through preexisting rock,...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified