Question 1

The sequence in which minerals crystallize in a cooling igneous melt is called Bowen's Reaction Series.

Accepted Answer

A) True 
 B)False  True

Question 2

What is the sequence of crystallization along the discontinuous branch of Bowen's reaction series?

Accepted Answer

A)   sodium-rich to calcium-rich plagioclase
B)   quartz, potassium feldspar, biotite
C)   silicic, felsic, mafic, intermediate
D)   olivine, pyroxene, amphibole, biotite
E)   framework, double chain, single chain, sheet, isolated D

Question 3

A pluton is an igneous structure that crystallized at very shallow depths.

Accepted Answer

A) True 
 B)False  False

Question 4

Mineralogically and chemically equivalent rocks are ___ and __.

Accepted Answer

A)   granite; rhyolite
B)   gabbro; basalt
C)   diorite; andesite
D)   mafic; ultramafic
E)   intermediate; felsic

Question 5

______ are fragments of country rock that are distinct from the body of igneous rocks in which they are enclosed.

Accepted Answer

A)   Clasts
B)   Chill zones
C)   Phenocrysts
D)   Xenoliths
E)   Necks

Question 6

The first plagioclase crystals to form as a hot melt cools are high in ______.

Accepted Answer

A)   iron
B)   calcium
C)   manganese
D)   carbonate
E)   lead

Question 7

Igneous rock names are based on grain shape and chemical composition.

Accepted Answer

A) True 
 B)False

Question 8

A ______ is an intrusive structure that formed from magma that solidified within the "throat" of a volcano.

Accepted Answer

A)   volcanic neck
B)   sill
C)   laccolith
D)   batholith
E)   diapir

Question 9

Igneous rocks that are silica-rich with high aluminum, sodium, and potassium are _____ rocks.

Accepted Answer

A)   silicic
B)   ultramafic
C)   mafic
D)   extraterrestrial
E)   intermediate

Question 10

On its slow journey through the crust, mafic magma evolves into intermediate magma by differentiation and assimilation of ______.

Accepted Answer

A)   mantle rocks
B)   basalt
C)   gabbro
D)   silicic rocks

Question 11

___ is a coarse-grained igneous rock (grains > 1 mm diameter) with visible grains of quartz.

Accepted Answer

A)   Gabbro
B)   Granite
C)   Basalt
D)   Peridotite
E)   Andesite

Question 12

Partial melting of the lower continental crust produces a silicic magma that eventually solidifies into granite or rhyolite.

Accepted Answer

A) True 
 B)False

Question 13

Mafic igneous rocks are silica-poor.

Accepted Answer

A) True 
 B)False

Question 14

___ are igneous rocks that are silica-deficient but high in iron and magnesium.

Accepted Answer

A)   Felsic
B)   Intermediate
C)   Oxide
D)   Mafic
E)   Sulfate

Question 15

Most of the basalt and gabbro on the ocean floor is created at mid oceanic ridges, which are also ____.

Accepted Answer

A)   divergent plate boundaries
B)   ocean-ocean convergent plate boundaries
C)   transform plate boundaries
D)   ocean-continent plate boundaries
E)   intraplate igneous areas

Question 16

Lava is magma on the Earth's surface.

Accepted Answer

A) True 
 B)False

Question 17

The crust beneath the world's oceans is mafic ________.

Accepted Answer

A)   iron
B)   asthenosphere
C)   granite and rhyolite
D)   basalt and gabbro
E)   Answers iron, asthenosphere, and granite and rhyolite are all correct.

Question 18

What type of melting takes place when a body of hot mantle rock moves upward and the pressure is reducted to the extent that the melting point drops to the temperature of the body?

Accepted Answer

A)   decompression melting
B)   subduction melting
C)   depressurized melting
D)   exfoliational melting
E)   mantle plume melting

Question 19

Crystal settling accounts for important deposits of ______.

Accepted Answer

A)   chromium and platinum
B)   gold
C)   lead and zinc
D)   iron
E)   aluminum and silicon

Question 20

The geothermal gradient for a volcanic region is greater than that for the continental interior.

Accepted Answer

A) True 
 B)False

Exam 3: Igneous Rocks, Intrusive Activity, and the Origin of Igneous Rocks

The sequence in which minerals crystallize in a cooling igneous melt is called Bowen's Reaction Series.

What is the sequence of crystallization along the discontinuous branch of Bowen's reaction series?

A pluton is an igneous structure that crystallized at very shallow depths.

Mineralogically and chemically equivalent rocks are _ and .

______ are fragments of country rock that are distinct from the body of igneous rocks in which they are enclosed.

The first plagioclase crystals to form as a hot melt cools are high in ______.

Igneous rock names are based on grain shape and chemical composition.

A ______ is an intrusive structure that formed from magma that solidified within the "throat" of a volcano.

Igneous rocks that are silica-rich with high aluminum, sodium, and potassium are _____ rocks.

On its slow journey through the crust, mafic magma evolves into intermediate magma by differentiation and assimilation of ______.

___ is a coarse-grained igneous rock (grains > 1 mm diameter) with visible grains of quartz.

Partial melting of the lower continental crust produces a silicic magma that eventually solidifies into granite or rhyolite.

Mafic igneous rocks are silica-poor.

___ are igneous rocks that are silica-deficient but high in iron and magnesium.

Most of the basalt and gabbro on the ocean floor is created at mid oceanic ridges, which are also ____.

Lava is magma on the Earth's surface.

The crust beneath the world's oceans is mafic ________.

What type of melting takes place when a body of hot mantle rock moves upward and the pressure is reducted to the extent that the melting point drops to the temperature of the body?

Crystal settling accounts for important deposits of ______.

The geothermal gradient for a volcanic region is greater than that for the continental interior.