Question 1

Volcanoes composed of multiple, overlapping volcanic domes are called a

Accepted Answer

A)  dome complex. 
B)  shield volcano. 
C)  composite volcano. 
D)  cinder cone. 
A)  dome complex. 
B)  shield volcano. 
C)  composite volcano. 
D)  cinder cone.

Question 2

Which igneous rocks are typically the lightest in color?

Accepted Answer

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

Question 3

Why is granite considered a coarse-grained felsic rock?

Accepted Answer

A)  It contains a lot of feldspar and silica. 
B)  It contains little feldspar and silica. 
C)  It contains a lot of magnesium and iron. 
D)  It contains a lot of feldspar and a little silica. 
A)  It contains a lot of feldspar and silica. 
B)  It contains little feldspar and silica. 
C)  It contains a lot of magnesium and iron. 
D)  It contains a lot of feldspar and a little silica.

Question 4

Figure 4.22  
-According to Figure 4.22 which types of magma can erupt as lava flows?

Accepted Answer

A)  Basaltic, Andesitic, and Dacitic 
B)  Basaltic, Andesitic, Dacitic and Rhyolitic 
C)  Basaltic and Andesitic 
D)  Basaltic 
A)  Basaltic, Andesitic, and Dacitic 
B)  Basaltic, Andesitic, Dacitic and Rhyolitic 
C)  Basaltic and Andesitic 
D)  Basaltic

Question 5

Which minerals usually give mafic and ultramafic rocks their dark colors?

Accepted Answer

A)  plagioclase feldspar and pyroxene 
B)  amphibole and pyroxene 
C)  olivine and pyroxene 
D)  plagioclase feldspar and olivine 
A)  plagioclase feldspar and pyroxene 
B)  amphibole and pyroxene 
C)  olivine and pyroxene 
D)  plagioclase feldspar and olivine

Question 6

Why are there different types of volcanoes and different volcanic eruptions? (4.8)

Accepted Answer

Volcanic phenomena and volcanic landform

Question 7

Why does Silica content in most magmas range from 45 to almost 80 percent by weight?

Accepted Answer

A)  Silica is very heavy and therefore throws off the percent weight. 
B)  Silica is made up of silicon and oxygen, two elements most prevalent in the earth's crust. 
C)  Silica is a very heavy gas. 
D)  Silica is extremely light. 
A)  Silica is very heavy and therefore throws off the percent weight. 
B)  Silica is made up of silicon and oxygen, two elements most prevalent in the earth's crust. 
C)  Silica is a very heavy gas. 
D)  Silica is extremely light.

Question 8

Why do igneous rocks have so many uses (anything from building stone to abrasive in toothpaste)?

Accepted Answer

A)  They are harmful to the environment, so we use them to prevent harm done. 
B)  They are very easy to attain. 
C)  They are strong because their finely intergrown mineral crystals are difficult to fracture along grain boundaries. 
D)  They are cheap. 
A)  They are harmful to the environment, so we use them to prevent harm done. 
B)  They are very easy to attain. 
C)  They are strong because their finely intergrown mineral crystals are difficult to fracture along grain boundaries. 
D)  They are cheap.

Question 9

Igneous rocks are overwhelmingly composed of silicate minerals. Why is this so?

Accepted Answer

A)  Silicates are very heavy. 
B)  Silicates compose a huge amount of the earth's crust. 
C)  Silicates are only found in igneous rocks. 
D)  Silicates are very rare. 
A)  Silicates are very heavy. 
B)  Silicates compose a huge amount of the earth's crust. 
C)  Silicates are only found in igneous rocks. 
D)  Silicates are very rare.

Question 10

How and why do rocks melt? (4.4)

Accepted Answer

Rocks melt gradually as the melting temp

Question 11

A sample contains 60 % Plagioclase Feldspar and a medium amount of silica. What would you call it?

Accepted Answer

A)  an intermediate igneous rock 
B)  a mafic igneous rock 
C)  an ultramafic igneous rock 
D)  a felsic igneous rock 
A)  an intermediate igneous rock 
B)  a mafic igneous rock 
C)  an ultramafic igneous rock 
D)  a felsic igneous rock

Question 12

Which is not a danger associated with volcanic ash?

Accepted Answer

A)  Ash gets caught in jet engines causing them to fail. 
B)  Ash can set fire to everything it falls on. 
C)  Ash can cause roofs to collapse. 
D)  Ash, if exposed to enough heat, can turn back to lava. 
A)  Ash gets caught in jet engines causing them to fail. 
B)  Ash can set fire to everything it falls on. 
C)  Ash can cause roofs to collapse. 
D)  Ash, if exposed to enough heat, can turn back to lava.

Question 13

Figure 4.22  
-According to Figure 4.22 which types of magma form cinder cones?

Accepted Answer

A)  Basaltic, Andesitic, and Dacitic 
B)  Basaltic, Andesitic, Dacitic and Rhyolitic 
C)  Basaltic and Andesitic 
D)  Basaltic 
A)  Basaltic, Andesitic, and Dacitic 
B)  Basaltic, Andesitic, Dacitic and Rhyolitic 
C)  Basaltic and Andesitic 
D)  Basaltic

Question 14

Why does Basaltic magma have the lowest viscosity?

Accepted Answer

A)  Basaltic lava has more silicate. 
B)  Basaltic lava has less silicate. 
C)  Basaltic lava is hotter than other flows. 
D)  Basaltic lava is less hot than other flows. 
A)  Basaltic lava has more silicate. 
B)  Basaltic lava has less silicate. 
C)  Basaltic lava is hotter than other flows. 
D)  Basaltic lava is less hot than other flows.

Question 15

Why are rocks rich in magnesium and iron called mafic?

Accepted Answer

A)  Mafic is the opposite of felsic. 
B)  Ferric is the same as mafic, which means rich in magnesium and iron. 
C)  Mafic comes from magnesium and ferric. 
D)  Mafic is the Latin word that means rich is magnesium and iron. 
A)  Mafic is the opposite of felsic. 
B)  Ferric is the same as mafic, which means rich in magnesium and iron. 
C)  Mafic comes from magnesium and ferric. 
D)  Mafic is the Latin word that means rich is magnesium and iron.

Question 16

What did Tuttle and Bowen observe in their experiment that helps geologists try to understand how magma is made? (4.5)

Accepted Answer

The melting temperature of granite is mu

Question 17

Why are rocks rich in feldspar and silica called felsic?

Accepted Answer

A)  Felsic is the Latin word that means rich in feldspar and silica. 
B)  Felsic is the opposite of mafic. 
C)  Felsic comes from feldspar and silica. 
D)  Felsic is the opposite of ultramafic. 
A)  Felsic is the Latin word that means rich in feldspar and silica. 
B)  Felsic is the opposite of mafic. 
C)  Felsic comes from feldspar and silica. 
D)  Felsic is the opposite of ultramafic.

Question 18

All igneous rocks exhibit identical grain size.

Accepted Answer

A) True 
 B)False

Question 19

What process forms rocks with porphyritic texture?

Accepted Answer

A)  quick cooling above ground 
B)  slow cooling below ground 
C)  a mixture of quick and slow cooling as rock moves from a warmer environment to a cooler one 
D)  slow cooling combined with pressure underground 
A)  quick cooling above ground 
B)  slow cooling below ground 
C)  a mixture of quick and slow cooling as rock moves from a warmer environment to a cooler one 
D)  slow cooling combined with pressure underground

Question 20

A geologist looks at a piece of rock from Yosemite National Park under a microscope and sees tiny crystals of olivine, pyroxene, and plagioclase feldspar. What process might have formed this rock?

Accepted Answer

A)  melting underground, violent volcanic eruption, and solidification above ground 
B)  melting underground, flowing to Earth's surface, and solidification above ground 
C)  solidification underground, violent volcanic eruption of ash and solid rock 
D)  both melting and crystallization underground 
A)  melting underground, violent volcanic eruption, and solidification above ground 
B)  melting underground, flowing to Earth's surface, and solidification above ground 
C)  solidification underground, violent volcanic eruption of ash and solid rock 
D)  both melting and crystallization underground

Exam 4: Formation of Magma and Igneous Rocks

Volcanoes composed of multiple, overlapping volcanic domes are called a

Which igneous rocks are typically the lightest in color?

Why is granite considered a coarse-grained felsic rock?

Figure 4.22 -According to Figure 4.22 which types of magma can erupt as lava flows?

Which minerals usually give mafic and ultramafic rocks their dark colors?

Why are there different types of volcanoes and different volcanic eruptions? (4.8)

Why does Silica content in most magmas range from 45 to almost 80 percent by weight?

Why do igneous rocks have so many uses (anything from building stone to abrasive in toothpaste)?

Igneous rocks are overwhelmingly composed of silicate minerals. Why is this so?

How and why do rocks melt? (4.4)

A sample contains 60 % Plagioclase Feldspar and a medium amount of silica. What would you call it?

Which is not a danger associated with volcanic ash?

Figure 4.22 -According to Figure 4.22 which types of magma form cinder cones?

Why does Basaltic magma have the lowest viscosity?

Why are rocks rich in magnesium and iron called mafic?

What did Tuttle and Bowen observe in their experiment that helps geologists try to understand how magma is made? (4.5)

Why are rocks rich in feldspar and silica called felsic?

All igneous rocks exhibit identical grain size.

What process forms rocks with porphyritic texture?

A geologist looks at a piece of rock from Yosemite National Park under a microscope and sees tiny crystals of olivine, pyroxene, and plagioclase feldspar. What process might have formed this rock?

Why Study Earth

Minerals: Building Blocks of the Planet

Rocks and Rock-Forming Processes

Formation of Sediment and Sedimentary Rocks

Formation of Metamorphic Rocks

Earth Materials As Time Keepers

Earth Materials As Time Keepers

Making Earth

Motion Inside Earth

Deformation of Rocks

Global Tectonics: Plates and Plumes

Tectonics and Surface Relief

Soil Formation and Landscape Stability

Mass Movements: Landscapes in Motion

Streams: Flowing Water Shapes the Landscape

Water Flowing Underground

Glaciers: Cold-Climate Sculptors of Continents

Shorelines: Changing Landscapes Where Land Meets Sea

Wind: a Global Geologic Process

Global Warming: Real Time Change in the Earth System

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