Question 1

The famous Mother Lode of the 1849 California gold rush is an example of

Accepted Answer

A) a basaltic dike. 
B) a hydrothermal vein. 
C) a volcanic tuff. 
D) a granitic pluton. 
A) a basaltic dike. 
B) a hydrothermal vein. 
C) a volcanic tuff. 
D) a granitic pluton.

Question 2

Which of the following best describes a rhyolite?

Accepted Answer

A) fine-grained igneous rock rich in silica 
B) fine-grained igneous rock poor in silica 
C) coarse-grained igneous rock rich in silica 
D) coarse-grained igneous rock poor in silica 
A) fine-grained igneous rock rich in silica 
B) fine-grained igneous rock poor in silica 
C) coarse-grained igneous rock rich in silica 
D) coarse-grained igneous rock poor in silica

Question 3

Which of the following statements is true?

Accepted Answer

A) Gabbro has a higher melting temperature than granite. 
B) Gabbro has a higher potassium content than granite. 
C) Gabbro has a higher silica content than granite. 
D) Gabbro has a higher viscosity than granite. 
A) Gabbro has a higher melting temperature than granite. 
B) Gabbro has a higher potassium content than granite. 
C) Gabbro has a higher silica content than granite. 
D) Gabbro has a higher viscosity than granite.

Question 4

What is the approximate silica content of granite?

Accepted Answer

A) 30% 
B) 50% 
C) 70% 
D) 90% 
A) 30% 
B) 50% 
C) 70% 
D) 90%

Question 5

Which of the following processes would most likely yield a granitic magma?

Accepted Answer

A) partial melting of subducted oceanic crust and sediments 
B) partial melting of the continental crust 
C) partial melting of the core 
D) partial melting of the upper mantle 
A) partial melting of subducted oceanic crust and sediments 
B) partial melting of the continental crust 
C) partial melting of the core 
D) partial melting of the upper mantle

Question 6

Which of the following types of igneous rocks are rarely found as lavas today?

Accepted Answer

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

Question 7

Which of the following minerals is rarely found in felsic igneous rocks?

Accepted Answer

A) olivine 
B) orthoclase feldspar 
C) plagioclase feldspar 
D) quartz 
A) olivine 
B) orthoclase feldspar 
C) plagioclase feldspar 
D) quartz

Question 8

Which of the following minerals is most likely to settle to the bottom of a magma chamber?

Accepted Answer

A) olivine 
B) plagioclase feldspar 
C) pyroxene 
D) quartz 
A) olivine 
B) plagioclase feldspar 
C) pyroxene 
D) quartz

Question 9

If a magma undergoes fractional crystallization,the remaining magma will be

Accepted Answer

A) more felsic. 
B) less viscous. 
C) more mafic. 
D) exactly the same. 
A) more felsic. 
B) less viscous. 
C) more mafic. 
D) exactly the same.

Question 10

Felsic igneous rocks contain abundant __________ silicate minerals.

Accepted Answer

A) double-chain 
B) framework 
C) isolated tetrahedra 
D) single-chain 
A) double-chain 
B) framework 
C) isolated tetrahedra 
D) single-chain

Question 11

Fluid-induced melting generates magmas in which of the following tectonic settings?

Accepted Answer

A) mantle plumes 
B) subduction zones 
C) mid-ocean ridges 
D) transform faults 
A) mantle plumes 
B) subduction zones 
C) mid-ocean ridges 
D) transform faults

Question 12

Which of the following statements about felsic igneous rocks is true?

Accepted Answer

A) Felsic rocks contain less silica than mafic rocks. 
B) Felsic rocks crystallize at lower temperatures than mafic rocks. 
C) Felsic rocks tend to be darker colored than mafic rocks. 
D) Felsic rocks tend to be finer grained than mafic rocks. 
A) Felsic rocks contain less silica than mafic rocks. 
B) Felsic rocks crystallize at lower temperatures than mafic rocks. 
C) Felsic rocks tend to be darker colored than mafic rocks. 
D) Felsic rocks tend to be finer grained than mafic rocks.

Question 13

What type of volcanic rock contains a large number of vesicles (bubbles)that form when gases escape from the solidifying melt?

Accepted Answer

A) granite 
B) obsidian 
C) porphyry 
D) pumice 
A) granite 
B) obsidian 
C) porphyry 
D) pumice

Question 14

Which of the following types of igneous rocks are rarely found as lavas?

Accepted Answer

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

Question 15

Which of the following pairs of intrusive and extrusive rocks have the same chemical composition?

Accepted Answer

A) diorite and rhyolite 
B) gabbro and rhyolite 
C) gabbro and basalt 
D) granite and andesite 
A) diorite and rhyolite 
B) gabbro and rhyolite 
C) gabbro and basalt 
D) granite and andesite

Question 16

At approximately what temperature do olivine and calcium-rich plagioclase feldspar crystallize from a mafic melt?

Accepted Answer

A) 300°C 
B) 600°C 
C) 1200°C 
D) 2000°C 
A) 300°C 
B) 600°C 
C) 1200°C 
D) 2000°C

Question 17

Which of the following igneous bodies is a concordant intrusive rock?

Accepted Answer

A) dike 
B) pluton 
C) sill 
D) stock 
A) dike 
B) pluton 
C) sill 
D) stock

Question 18

Which of the following lists is in the correct order of increasing silica content?

Accepted Answer

A) diorite,granite,gabbro 
B) gabbro,diorite,granite 
C) gabbro,granite,diorite 
D) granite,diorite,gabbro 
A) diorite,granite,gabbro 
B) gabbro,diorite,granite 
C) gabbro,granite,diorite 
D) granite,diorite,gabbro

Question 19

The presence of water will ________ the melting temperature of a rock.

Accepted Answer

A) increase 
B) raise 
C) decrease 
D) not affect 
A) increase 
B) raise 
C) decrease 
D) not affect

Question 20

The largest forms of igneous intrusions are called

Accepted Answer

A) plutons. 
B) stocks. 
C) sills. 
D) batholiths. 
A) plutons. 
B) stocks. 
C) sills. 
D) batholiths.

Exam 4: Igneous Rocks: Solids From Melts

The famous Mother Lode of the 1849 California gold rush is an example of

Which of the following best describes a rhyolite?

Which of the following statements is true?

What is the approximate silica content of granite?

Which of the following processes would most likely yield a granitic magma?

Which of the following types of igneous rocks are rarely found as lavas today?

Which of the following minerals is rarely found in felsic igneous rocks?

Which of the following minerals is most likely to settle to the bottom of a magma chamber?

If a magma undergoes fractional crystallization,the remaining magma will be

Felsic igneous rocks contain abundant __________ silicate minerals.

Fluid-induced melting generates magmas in which of the following tectonic settings?

Which of the following statements about felsic igneous rocks is true?

What type of volcanic rock contains a large number of vesicles (bubbles)that form when gases escape from the solidifying melt?

Which of the following types of igneous rocks are rarely found as lavas?

Which of the following pairs of intrusive and extrusive rocks have the same chemical composition?

At approximately what temperature do olivine and calcium-rich plagioclase feldspar crystallize from a mafic melt?

Which of the following igneous bodies is a concordant intrusive rock?

Which of the following lists is in the correct order of increasing silica content?

The presence of water will ________ the melting temperature of a rock.

The largest forms of igneous intrusions are called

The Earth System

Plate Tectonics: The Unifying Theory

Earth Materials: Minerals and Rocks

Sedimentation: Rocks Formed by Surface Processes

Metamorphism: Alteration of Rocks by Temperature and Pressure

Deformation: Modification of Rocks by Folding and Fracturing

Clocks in Rocks: Timing the Geologic Period

Early History of the Terrestrial Planets

History of the Continents

Geobiology: Life Interacts With Earth

Volcanoes

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Exploring Earths Interior

The Climate System

Weathering,erosion,and Mass Wasting: Interactions Between the Climate and Plate Tectonic Systems

The Hydrologic Cycle and Groundwater

Stream Transport: From Mountains to Oceans

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Coastlines and Ocean Basins

Glaciers: the Work of Ice

Landscapes: Tectonic and Climate Interaction

The Human Impact of Earths Environment

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