Question 1

Which of the following is an example of a mafic igneous rock?

Accepted Answer

A)  Gabbro. 
B)  Andesite. 
C)  Granite. 
D)  Rhyolite. 
A)  Gabbro. 
B)  Andesite. 
C)  Granite. 
D)  Rhyolite. A

Question 2

Batholiths are primarily composed of intermediate and felsic compositions. A few ancient batholiths that formed several billion years ago are mafic. Why is this the case?

Accepted Answer

The characteristics of intermediate and felsic magmas help to answer this question. These magmas occur at relatively low temperatures, which allows them to persist within the crust for large amounts of time. The viscous nature and high silica content of these magmas prevents rapid movement towards the surface, and gases trapped within the viscous magmas build pressures that force the rock apart to accommodate the cooling magma. In the first few billion years, the Earth's crust was much hotter than it is today, allowing ultramafic (komatiite) lavas to rise to the surface, and mafic magmas to cool within the crust, producing gabbroic(mafic) batholiths. Today, the Earth's surface is only warm enough to allow mafic magmas to reach the surface to form basaltic lavas.

Question 3

Which is a common rock found on both the Moon and the Earth?

Accepted Answer

A)  Andesite. 
B)  Granite. 
C)  Basalt. 
D)  Rhyolite. 
A)  Andesite. 
B)  Granite. 
C)  Basalt. 
D)  Rhyolite. C

Question 4

The classification of intrusive igneous structures depends on all of the following EXCEPT:

Accepted Answer

A)  orientation with country rock. 
B)  size. 
C)  shape. 
D)  composition and texture. 
A)  orientation with country rock. 
B)  size. 
C)  shape. 
D)  composition and texture.

Question 5

Plutonic rocks are characterized by which type of texture?

Accepted Answer

A)  Glassy. 
B)  Aphanitic. 
C)  Phaneritic. 
D)  Vesicular. 
A)  Glassy. 
B)  Aphanitic. 
C)  Phaneritic. 
D)  Vesicular.

Question 6

Explain the correlation between Bowen's reaction series and various igneous rock compositions.

Accepted Answer

The minerals formed early during the rea

Question 7

Which process accounts for the vast areas of intermediate and felsic rock seen in nature?

Accepted Answer

A)  Crystal settling. 
B)  Intrusion. 
C)  Magma mixing. 
D)  Extrusion. 
A)  Crystal settling. 
B)  Intrusion. 
C)  Magma mixing. 
D)  Extrusion.

Question 8

An aphanitic mafic rock is a:

Accepted Answer

A)  gabbro. 
B)  basalt. 
C)  rhyolite. 
D)  granite. 
A)  gabbro. 
B)  basalt. 
C)  rhyolite. 
D)  granite.

Question 9

Diorite is an example of an:

Accepted Answer

A)  extrusive felsic rock. 
B)  extrusive intermediate rock. 
C)  intrusive intermediate rock. 
D)  intrusive felsic rock. 
A)  extrusive felsic rock. 
B)  extrusive intermediate rock. 
C)  intrusive intermediate rock. 
D)  intrusive felsic rock.

Question 10

As the rate of cooling decreases, particle size in an igneous rock:

Accepted Answer

A)  can not predict. 
B)  stays the same. 
C)  increases. 
D)  decreases. 
A)  can not predict. 
B)  stays the same. 
C)  increases. 
D)  decreases.

Question 11

The two properties used most to classify igneous rocks are:

Accepted Answer

A)  the grain size and the number of different minerals present. 
B)  color and mineral composition. 
C)  color and texture. 
D)  texture and mineral composition. 
A)  the grain size and the number of different minerals present. 
B)  color and mineral composition. 
C)  color and texture. 
D)  texture and mineral composition.

Question 12

Continental Basalts are frequently found:

Accepted Answer

A)  where rifts open old continental plates. 
B)  above oceanic hot spots. 
C)  near colliding continental plates. 
D)  along transform plate boundaries. 
A)  where rifts open old continental plates. 
B)  above oceanic hot spots. 
C)  near colliding continental plates. 
D)  along transform plate boundaries.

Question 13

As pressure increases, the melting- point of a rock:

Accepted Answer

A)  can not predict. 
B)  stays the same. 
C)  decreases. 
D)  increases. 
A)  can not predict. 
B)  stays the same. 
C)  decreases. 
D)  increases.

Question 14

The fractional crystallization of mafic magmas into both mafic and felsic rocks cannot account for all the igneous rocks in existence. What other processes can be used to explain why felsic igneous rocks are so abundant?

Accepted Answer

As magma moves upward, blocks and pieces

Question 15

List and define the two properties by which igneous rocks are classified.

Accepted Answer

The two properties are texture and compo

Question 16

An ultramafic igneous rock is one that contains about how much silica?

Accepted Answer

A)  Greater than 65%. 
B)  55% to 65%. 
C)  Less than 40%. 
D)  45% to 55%. 
A)  Greater than 65%. 
B)  55% to 65%. 
C)  Less than 40%. 
D)  45% to 55%.

Question 17

An igneous structure produced by deep- seated, extremely gaseous, highly explosive eruptions is:

Accepted Answer

A)  a diapir. 
B)  a batholith. 
C)  a dike. 
D)  a diatreme. 
A)  a diapir. 
B)  a batholith. 
C)  a dike. 
D)  a diatreme.

Question 18

Why do the terms aphanitic or phaneritic not apply to the texture of pumice or obsidian?

Accepted Answer

The terms aphanitic and phaneritic descr

Question 19

A phaneritic rock containing a relatively high percentage of silica is a:

Accepted Answer

A)  granite. 
B)  gabbro. 
C)  rhyolite. 
D)  basalt. 
A)  granite. 
B)  gabbro. 
C)  rhyolite. 
D)  basalt.

Question 20

Describe how the factors of heat, pressure, and water content influence the melting point temperature of crustal rocks.

Accepted Answer

Crustal rocks are heated from three sour

Which of the following is an example of a mafic igneous rock?

Batholiths are primarily composed of intermediate and felsic compositions. A few ancient batholiths that formed several billion years ago are mafic. Why is this the case?

Which is a common rock found on both the Moon and the Earth?

The classification of intrusive igneous structures depends on all of the following EXCEPT:

Plutonic rocks are characterized by which type of texture?

Explain the correlation between Bowen's reaction series and various igneous rock compositions.

Which process accounts for the vast areas of intermediate and felsic rock seen in nature?

An aphanitic mafic rock is a:

Diorite is an example of an:

As the rate of cooling decreases, particle size in an igneous rock:

The two properties used most to classify igneous rocks are:

Continental Basalts are frequently found:

As pressure increases, the melting- point of a rock:

The fractional crystallization of mafic magmas into both mafic and felsic rocks cannot account for all the igneous rocks in existence. What other processes can be used to explain why felsic igneous rocks are so abundant?

List and define the two properties by which igneous rocks are classified.

An ultramafic igneous rock is one that contains about how much silica?

An igneous structure produced by deep- seated, extremely gaseous, highly explosive eruptions is:

Why do the terms aphanitic or phaneritic not apply to the texture of pumice or obsidian?

A phaneritic rock containing a relatively high percentage of silica is a:

Describe how the factors of heat, pressure, and water content influence the melting point temperature of crustal rocks.

A First Look at Planet Earth - Its Origins, Systems, and Tectonic Plates

Minerals

Volcanoes and Volcanism

Weathering - the Breakdown of Rocks

Sedimentary Processes, Environments, and Rocks

Metamorphism and Metamorphic Rocks

Telling Time Geologically

Earth Structures - Folds, Faults, and Fabrics

Earthquakes

The Earths Interior - Whats Going on Down There

Plate Tectonics and the Formation of the Earths Oceans

Continental Tectonics and the Formation of the Earths Continents

Mass Movement

Streams and Floods

Groundwater

Glaciers and Ice Ages

Deserts and the Work of Winds

Shores and Coastal Processes

Human Use of the Earths Resources Appendices Glossary

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Exam 3: Igneous Rocks and Processes

Which of the following is an example of a mafic igneous rock?

Batholiths are primarily composed of intermediate and felsic compositions. A few ancient batholiths that formed several billion years ago are mafic. Why is this the case?

Which is a common rock found on both the Moon and the Earth?

The classification of intrusive igneous structures depends on all of the following EXCEPT:

Plutonic rocks are characterized by which type of texture?

Explain the correlation between Bowen's reaction series and various igneous rock compositions.

Which process accounts for the vast areas of intermediate and felsic rock seen in nature?

An aphanitic mafic rock is a:

Diorite is an example of an:

As the rate of cooling decreases, particle size in an igneous rock:

The two properties used most to classify igneous rocks are:

Continental Basalts are frequently found:

As pressure increases, the melting- point of a rock:

The fractional crystallization of mafic magmas into both mafic and felsic rocks cannot account for all the igneous rocks in existence. What other processes can be used to explain why felsic igneous rocks are so abundant?

List and define the two properties by which igneous rocks are classified.

An ultramafic igneous rock is one that contains about how much silica?

An igneous structure produced by deep- seated, extremely gaseous, highly explosive eruptions is:

Why do the terms aphanitic or phaneritic not apply to the texture of pumice or obsidian?

A phaneritic rock containing a relatively high percentage of silica is a:

Describe how the factors of heat, pressure, and water content influence the melting point temperature of crustal rocks.

A First Look at Planet Earth - Its Origins, Systems, and Tectonic Plates

Minerals

Volcanoes and Volcanism

Weathering - the Breakdown of Rocks

Sedimentary Processes, Environments, and Rocks

Metamorphism and Metamorphic Rocks

Telling Time Geologically

Earth Structures - Folds, Faults, and Fabrics

Earthquakes

The Earths Interior - Whats Going on Down There

Plate Tectonics and the Formation of the Earths Oceans

Continental Tectonics and the Formation of the Earths Continents

Mass Movement

Streams and Floods

Groundwater

Glaciers and Ice Ages

Deserts and the Work of Winds

Shores and Coastal Processes

Human Use of the Earths Resources Appendices Glossary

Filters