Question 1

At the Earth's surface, the mineral albite melts at 1118° C. At a depth of 100 km, it would melt at:

Accepted Answer

A)  900° C. 
B)  1100° C. 
C)  1440° C. 
D)  750° C. 
A)  900° C. 
B)  1100° C. 
C)  1440° C. 
D)  750° C.

Question 2

All of the following are differences between MORBs and OIBs EXCEPT:

Accepted Answer

A)  MORBs are composed of basalts, and OIBs are composed of gabbros. 
B)  MORBs probably formed from partial melting of the upper mantle, and OIBs probably formed from a deep part of the mantle. 
C)  MORBs contain less potassium and uranium than OIBs. 
D)  MORBs occur at divergent plate boundaries, and OIBs occur over hot spots. 
A)  MORBs are composed of basalts, and OIBs are composed of gabbros. 
B)  MORBs probably formed from partial melting of the upper mantle, and OIBs probably formed from a deep part of the mantle. 
C)  MORBs contain less potassium and uranium than OIBs. 
D)  MORBs occur at divergent plate boundaries, and OIBs occur over hot spots.

Question 3

Obsidian is dark- colored because of its:

Accepted Answer

A)  high concentrations of amphibole. 
B)  high concentration of iron and magnesium. 
C)  because it is a mafic rock. 
D)  minute iron minerals scattered throughout the glass. 
A)  high concentrations of amphibole. 
B)  high concentration of iron and magnesium. 
C)  because it is a mafic rock. 
D)  minute iron minerals scattered throughout the glass.

Question 4

All of the following represent typical tectonic settings for the occurrence of the specified rock type EXCEPT:

Accepted Answer

A)  granite at continental rifts. 
B)  andesite at subduction zones. 
C)  continental basalts at continental rifts. 
D)  rhyolite at subduction zones. 
A)  granite at continental rifts. 
B)  andesite at subduction zones. 
C)  continental basalts at continental rifts. 
D)  rhyolite at subduction zones.

Question 5

The geothermal gradient describes how:

Accepted Answer

A)  pressure increases with depth within the Earth. 
B)  temperature increases with depth within the Earth. 
C)  water content increases with depth within the Earth. 
D)  magma becomes more mafic with depth within the Earth. 
A)  pressure increases with depth within the Earth. 
B)  temperature increases with depth within the Earth. 
C)  water content increases with depth within the Earth. 
D)  magma becomes more mafic with depth within the Earth.

Question 6

The temperature at which a mineral melts:

Accepted Answer

A)  is the same temperature at which it crystallizes. 
B)  is higher than the temperature at which it crystallizes. 
C)  is lower than the temperature at which it crystallizes. 
D)  is much higher than the temperature at which it crystallizes. 
A)  is the same temperature at which it crystallizes. 
B)  is higher than the temperature at which it crystallizes. 
C)  is lower than the temperature at which it crystallizes. 
D)  is much higher than the temperature at which it crystallizes.

Question 7

Where are most igneous rocks found?

Accepted Answer

A)  Either within plates or at plate boundaries. 
B)  At or near plate boundaries. 
C)  Within plates. 
D)  No relationship exists. 
A)  Either within plates or at plate boundaries. 
B)  At or near plate boundaries. 
C)  Within plates. 
D)  No relationship exists.

Question 8

The rocks that make up the oceanic crust are all:

Accepted Answer

A)  basalts and gabbros. 
B)  andesites and diorites. 
C)  aphanitic (rhyolites, andesites, and basalts) because they were cooled rapidly by ocean water. 
D)  rhyolites and granites. 
A)  basalts and gabbros. 
B)  andesites and diorites. 
C)  aphanitic (rhyolites, andesites, and basalts) because they were cooled rapidly by ocean water. 
D)  rhyolites and granites.

Question 9

The texture of obsidian and pumice is:

Accepted Answer

A)  phaneritic, resulting from slow cooling. 
B)  aphanitic, resulting from rapid cooling. 
C)  porphyritic, resulting from first slow, then rapid, cooling. 
D)  glassy, resulting from rapid cooling. 
A)  phaneritic, resulting from slow cooling. 
B)  aphanitic, resulting from rapid cooling. 
C)  porphyritic, resulting from first slow, then rapid, cooling. 
D)  glassy, resulting from rapid cooling.

Question 10

Which of the following is NOT true about Bowen's reaction series?

Accepted Answer

A)  It shows how silicate minerals form as temperature decreases. 
B)  It shows how a complete range of igneous rock compositions may be formed from the same basaltic magma. 
C)  It shows that minerals never form in the same order. 
D)  It shows that minerals form in a definite sequence. 
A)  It shows how silicate minerals form as temperature decreases. 
B)  It shows how a complete range of igneous rock compositions may be formed from the same basaltic magma. 
C)  It shows that minerals never form in the same order. 
D)  It shows that minerals form in a definite sequence.

Question 11

Which of the following statements concerning cooling magma is NOT true?

Accepted Answer

A)  Different minerals crystallize at different temperatures. 
B)  Composition of the magma remains the same as it crystallizes. 
C)  Crystals grow until they touch the edges of other crystals. 
D)  As magma cools, new bonds form between ions. 
A)  Different minerals crystallize at different temperatures. 
B)  Composition of the magma remains the same as it crystallizes. 
C)  Crystals grow until they touch the edges of other crystals. 
D)  As magma cools, new bonds form between ions.

Question 12

In an igneous rock with two distinct classes of crystal size, which of the following is true?

Accepted Answer

A)  The rock cooled quickly at first, but then the cooling process slowed down. 
B)  There was an explosion producing different sized crystals. 
C)  The rock cooled slowly at first, but then the cooling process speeded up. 
D)  The minerals were all large, but then some melted. 
A)  The rock cooled quickly at first, but then the cooling process slowed down. 
B)  There was an explosion producing different sized crystals. 
C)  The rock cooled slowly at first, but then the cooling process speeded up. 
D)  The minerals were all large, but then some melted.

Question 13

Which of the following statements concerning batholiths is NOT true?

Accepted Answer

A)  They commonly consist of the mafic intrusive rock gabbro. 
B)  They often form the cores of mountain ranges. 
C)  They are at least 100 square kilometers (40 square miles) in surface area. 
D)  They are massive discordant igneous bodies. 
A)  They commonly consist of the mafic intrusive rock gabbro. 
B)  They often form the cores of mountain ranges. 
C)  They are at least 100 square kilometers (40 square miles) in surface area. 
D)  They are massive discordant igneous bodies.

Question 14

An ultramafic rock has the highest proportion of:

Accepted Answer

A)  iron and aluminum. 
B)  potassium and aluminum. 
C)  iron and magnesium. 
D)  oxygen and silicon. 
A)  iron and aluminum. 
B)  potassium and aluminum. 
C)  iron and magnesium. 
D)  oxygen and silicon.

Question 15

Why are basalt and gabbro the only igneous rocks in oceanic crust?

Accepted Answer

Oceanic crust is formed at divergent pla

Question 16

Which of the following is an example of an intermediate igneous rock?

Accepted Answer

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

Question 17

A laccolith is a:

Accepted Answer

A)  domed, concordant pluton. 
B)  massive discordant pluton. 
C)  saucer- shaped, concordant pluton. 
D)  discordant tabular pluton. 
A)  domed, concordant pluton. 
B)  massive discordant pluton. 
C)  saucer- shaped, concordant pluton. 
D)  discordant tabular pluton.

Question 18

List and describe four economic uses for igneous rocks.

Accepted Answer

Granite and diorite are used for buildin

Question 19

What is the last mineral to form according to Bowen's reaction series?

Accepted Answer

A)  Olivine. 
B)  Quartz. 
C)  Calcium plagioclase. 
D)  Muscovite. 
A)  Olivine. 
B)  Quartz. 
C)  Calcium plagioclase. 
D)  Muscovite.

Question 20

The term texture refers to:

Accepted Answer

A)  the kinds of minerals that constitute the rock. 
B)  the appearance of irregularities on the rock surface. 
C)  the size and shape of the mineral components. 
D)  whether the rock feels smooth or gritty. 
A)  the kinds of minerals that constitute the rock. 
B)  the appearance of irregularities on the rock surface. 
C)  the size and shape of the mineral components. 
D)  whether the rock feels smooth or gritty.

At the Earth's surface, the mineral albite melts at 1118° C. At a depth of 100 km, it would melt at:

All of the following are differences between MORBs and OIBs EXCEPT:

Obsidian is dark- colored because of its:

All of the following represent typical tectonic settings for the occurrence of the specified rock type EXCEPT:

The geothermal gradient describes how:

The temperature at which a mineral melts:

Where are most igneous rocks found?

The rocks that make up the oceanic crust are all:

The texture of obsidian and pumice is:

Which of the following is NOT true about Bowen's reaction series?

Which of the following statements concerning cooling magma is NOT true?

In an igneous rock with two distinct classes of crystal size, which of the following is true?

Which of the following statements concerning batholiths is NOT true?

An ultramafic rock has the highest proportion of:

Why are basalt and gabbro the only igneous rocks in oceanic crust?

Which of the following is an example of an intermediate igneous rock?

A laccolith is a:

List and describe four economic uses for igneous rocks.

What is the last mineral to form according to Bowen's reaction series?

The term texture refers to:

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

Exam 3: Igneous Rocks and Processes

At the Earth's surface, the mineral albite melts at 1118° C. At a depth of 100 km, it would melt at:

All of the following are differences between MORBs and OIBs EXCEPT:

Obsidian is dark- colored because of its:

All of the following represent typical tectonic settings for the occurrence of the specified rock type EXCEPT:

The geothermal gradient describes how:

The temperature at which a mineral melts:

Where are most igneous rocks found?

The rocks that make up the oceanic crust are all:

The texture of obsidian and pumice is:

Which of the following is NOT true about Bowen's reaction series?

Which of the following statements concerning cooling magma is NOT true?

In an igneous rock with two distinct classes of crystal size, which of the following is true?

Which of the following statements concerning batholiths is NOT true?

An ultramafic rock has the highest proportion of:

Why are basalt and gabbro the only igneous rocks in oceanic crust?

Which of the following is an example of an intermediate igneous rock?

A laccolith is a:

List and describe four economic uses for igneous rocks.

What is the last mineral to form according to Bowen's reaction series?

The term texture refers to:

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