Question 1

A volcanic neck,such as that seen at Shiprock,New Mexico (below),is a(n)____________.

Accepted Answer

A) sheet-like intrusion that lies parallel to surrounding layers of sedimentary rock 
B) cooled layer of lava 
C) intrusion formed within the magma chamber of a volcano 
D) sheet-like intrusion that cuts across preexisting layers 
A) sheet-like intrusion that lies parallel to surrounding layers of sedimentary rock 
B) cooled layer of lava 
C) intrusion formed within the magma chamber of a volcano 
D) sheet-like intrusion that cuts across preexisting layers C

Question 2

Radioactive isotopes,differentiation of Earth's iron core,gravity-driven compression,and meteoric bombardment all caused early Earth to ____________.

Accepted Answer

A) glow brighter than the Sun 
B) be much cooler than at present 
C) be much hotter than at present 
D) be much more oblong than at present 
A) glow brighter than the Sun 
B) be much cooler than at present 
C) be much hotter than at present 
D) be much more oblong than at present C

Question 3

If a body of magma is subjected to fractional crystallization,the rock that results is expected to be ____________.

Accepted Answer

A) identical in chemical composition to the magma 
B) more mafic than the magma 
C) more felsic than the magma 
A) identical in chemical composition to the magma 
B) more mafic than the magma 
C) more felsic than the magma B

Question 4

An island volcanic arc occurs at ____________.

Accepted Answer

A) the Aleutian Islands of Alaska 
B) the Andes Mountains 
C) Hawaii 
D) Mt.St.Helens,Washington 
A) the Aleutian Islands of Alaska 
B) the Andes Mountains 
C) Hawaii 
D) Mt.St.Helens,Washington

Question 5

A majority of the melts in the Earth form through the partial melting of ultramafic mantle rock.These newly formed magmas are ____________.

Accepted Answer

A) ultramafic 
B) mafic 
C) felsic 
D) intermediate 
A) ultramafic 
B) mafic 
C) felsic 
D) intermediate

Question 6

A volcano emits ash,which falls from the sky,settles in layers,and is eventually cemented.The resulting rock is termed ____________.

Accepted Answer

A) pumice 
B) granite 
C) tuff 
D) ignimbrite 
A) pumice 
B) granite 
C) tuff 
D) ignimbrite

Question 7

A blob-like igneous rock body that has cooled beneath the surface of Earth is ____________.

Accepted Answer

A) guyot 
B) pluton 
C) lava flow 
D) andesite 
A) guyot 
B) pluton 
C) lava flow 
D) andesite

Question 8

The geotherm is the rate of change of ____________.

Accepted Answer

A) pressure with depth in Earth's interior 
B) temperature with depth in Earth's interior 
C) temperature with altitude in Earth's atmosphere 
D) temperature with latitude on Earth's surface 
A) pressure with depth in Earth's interior 
B) temperature with depth in Earth's interior 
C) temperature with altitude in Earth's atmosphere 
D) temperature with latitude on Earth's surface

Question 9

If the volatile content of magma is increased,its viscosity will ____________.

Accepted Answer

A) increase 
B) decrease 
C) stay the same 
A) increase 
B) decrease 
C) stay the same

Question 10

Igneous rocks ____________.

Accepted Answer

A) are formed through the freezing of melt 
B) can be produced at the surface of the Earth as well as deep below the surface 
C) are the most common type of rocks within Earth 
D) All of the above are correct. 
A) are formed through the freezing of melt 
B) can be produced at the surface of the Earth as well as deep below the surface 
C) are the most common type of rocks within Earth 
D) All of the above are correct.

Question 11

As compared to mafic igneous rocks,all felsic igneous rocks ____________.

Accepted Answer

A) cool and solidify more quickly 
B) cool and solidify more slowly 
C) solidify at higher temperatures 
D) solidify at lower temperatures 
A) cool and solidify more quickly 
B) cool and solidify more slowly 
C) solidify at higher temperatures 
D) solidify at lower temperatures

Question 12

Which type of magma has the greatest silica content?

Accepted Answer

A) felsic 
B) intermediate 
C) mafic 
D) ultramafic 
A) felsic 
B) intermediate 
C) mafic 
D) ultramafic

Question 13

The difference between magma and lava is ____________.

Accepted Answer

A) magma cools more rapidly than lava 
B) magma is found at the surface,whereas lava is found below the surface 
C) magma is found beneath the surface,whereas lava is found at the surface 
D) There is no difference;the two terms mean the same thing. 
A) magma cools more rapidly than lava 
B) magma is found at the surface,whereas lava is found below the surface 
C) magma is found beneath the surface,whereas lava is found at the surface 
D) There is no difference;the two terms mean the same thing.

Question 14

The formation of magma within Earth is NOT caused by which of the following processes?

Accepted Answer

A) decompression (drop in pressure) 
B) addition of volatiles 
C) transfer of heat from adjacent magma or very hot rocks 
D) loss of volatiles to the atmosphere 
A) decompression (drop in pressure) 
B) addition of volatiles 
C) transfer of heat from adjacent magma or very hot rocks 
D) loss of volatiles to the atmosphere

Question 15

Ash and lava fragments that cascade down the sides of a volcano eventually settle and lithify to form ____________.

Accepted Answer

A) basalt 
B) andesite 
C) welded tuff 
D) ash-fall tuff 
A) basalt 
B) andesite 
C) welded tuff 
D) ash-fall tuff

Question 16

Important volatiles in magmas include ____________.

Accepted Answer

A) iron- and magnesium-rich minerals,such as olivine 
B) potassium and aluminum 
C) water and carbon dioxide 
D) trinitrotoluene and nitroglycerin 
A) iron- and magnesium-rich minerals,such as olivine 
B) potassium and aluminum 
C) water and carbon dioxide 
D) trinitrotoluene and nitroglycerin

Question 17

An igneous rock with a mixed texture of coarse grains (phenocrysts)surrounded by fine crystals (groundmass)is termed ____________.

Accepted Answer

A) porphyritic 
B) phaneritic 
C) aphanitic 
D) necrotic 
A) porphyritic 
B) phaneritic 
C) aphanitic 
D) necrotic

Question 18

Most commonly,felsic igneous rocks ____________.

Accepted Answer

A) contain more iron and magnesium than intermediate rocks 
B) are lighter in color than mafic rocks 
C) are darker in color than mafic rocks 
D) are found in oceanic crust 
A) contain more iron and magnesium than intermediate rocks 
B) are lighter in color than mafic rocks 
C) are darker in color than mafic rocks 
D) are found in oceanic crust

Question 19

Pillow basalts,shown below,attain their distinctive blob-like shapes because their parent lavas do not travel far prior to solidification.This is because the parent lavas ____________.

Accepted Answer

A) are completely devoid of volatiles and thus travel slowly 
B) erupt underwater and thus cool very quickly 
C) are highly felsic and thus travel slowly 
D) are ultramafic and thus freeze at exceptionally high temperatures 
A) are completely devoid of volatiles and thus travel slowly 
B) erupt underwater and thus cool very quickly 
C) are highly felsic and thus travel slowly 
D) are ultramafic and thus freeze at exceptionally high temperatures

Question 20

Very early in Earth's history,it was so hot that the surface was likely entirely molten.

Accepted Answer

A) True 
 B)False

Exam 6: Up From the Inferno: Magma and Igneous Rock

A volcanic neck,such as that seen at Shiprock,New Mexico (below),is a(n)____________.

Radioactive isotopes,differentiation of Earth's iron core,gravity-driven compression,and meteoric bombardment all caused early Earth to ____________.

If a body of magma is subjected to fractional crystallization,the rock that results is expected to be ____________.

An island volcanic arc occurs at ____________.

A majority of the melts in the Earth form through the partial melting of ultramafic mantle rock.These newly formed magmas are ____________.

A volcano emits ash,which falls from the sky,settles in layers,and is eventually cemented.The resulting rock is termed ____________.

A blob-like igneous rock body that has cooled beneath the surface of Earth is ____________.

The geotherm is the rate of change of ____________.

If the volatile content of magma is increased,its viscosity will ____________.

Igneous rocks ____________.

As compared to mafic igneous rocks,all felsic igneous rocks ____________.

Which type of magma has the greatest silica content?

The difference between magma and lava is ____________.

The formation of magma within Earth is NOT caused by which of the following processes?

Ash and lava fragments that cascade down the sides of a volcano eventually settle and lithify to form ____________.

Important volatiles in magmas include ____________.

An igneous rock with a mixed texture of coarse grains (phenocrysts)surrounded by fine crystals (groundmass)is termed ____________.

Most commonly,felsic igneous rocks ____________.

Pillow basalts,shown below,attain their distinctive blob-like shapes because their parent lavas do not travel far prior to solidification.This is because the parent lavas ____________.

Very early in Earth's history,it was so hot that the surface was likely entirely molten.

Cosmology and the Birth of Earth

Journey to the Center of the Earth

Drifting Continents and Spreading Seas

The Way the Earth Works: Plate Tectonics

Patterns in Nature: Minerals

Pages of Earths Past: Sedimentary Rocks

Metamorphism: A Process of Change

The Wrath of Vulcan: Volcanic Eruptions

A Violent Pulse: Earthquakes

Cracks, crags, and Crumples: Crustal Deformation and Mountain Building

Deep Time: How Old Is Old

A Biography of Earth

Squeezing Power From a Stone: Energy Resources

Riches in Rock: Mineral Resources

Unsafe Ground: Landslides and Other Mass Movements

Streams and Floods: The Geology of Running Water

Restless Realm: Oceans and Coasts

A Hidden Reserve: Groundwater

An Envelope of Gas: Earths Atmosphere and Climate

Dry Settings: the Geology of Deserts

Amazing Ice: Glaciers and Ice Ages

Global Change in the Earth System

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