Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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As
the water content of rock increases, the melting point ____. a. | first increases,
then decreases | c. | decreases | b. | remains the same | d. | increases | | | | |
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2.
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A
model that illustrates the predictable patterns of mineral formation from cooling magma is
____. a. | Bowen's reaction
series | c. | layered
intrusion formation | b. | crystal separation | d. | mineral composition | | | | |
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3.
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Intrusive igneous rocks form ____. a. | fine-grained rocks | b. | when a molten
mass of rocks cools quickly | c. | on Earth's surface | d. | coarse-grained
rocks | | |
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4.
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Rocks are
formed when magma ____. a. | erodes | c. | crystallizes | b. | undergoes radioactive
decay | d. | weathers | | | | |
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5.
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Igneous
rocks that cool slowly beneath Earth’s crust are ____. a. | extrusive | c. | sedimentary | b. | intrusive | d. | always magnetic | | | | |
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6.
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Igneous
rocks that cool quickly on Earth’s surface are ____. a. | extrusive | c. | metamorphic | b. | intrusive | d. | always magnetic | | | | |
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7.
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Extrusive
rocks, which cool more rapidly than intrusive rocks, are generally more ____. a. | coarsely
grained | c. | radioactive | b. | finely grained | d. | magnetic | | | | |
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8.
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Factors that
affect a rock’s melting point include ____. a. | pressure and water content | c. | rarity | b. | value as a gem | d. | usefulness as a building material | | | | |
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9.
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Valuable ore
deposits and gem crystals are often associated with ____. a. | oceans | c. | thin crustal
areas | b. | oil deposits | d. | igneous intrusions | | | | |
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Matching
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Match each item with the correct statement below. a. | felsic | e. | pegmatite | b. | kimberlite | f. | porphyritic | c. | lava | g. | ultramafic | d. | mafic | | | | |
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10.
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Magma
that flows out onto Earth's surface
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11.
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Dark-colored rock such as gabbro that is rich in iron and magnesium
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12.
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Rock
that is very high in iron and magnesium
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13.
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Vein
of extremely large-grained minerals
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14.
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Ultramafic rock that can contains diamonds
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Short Answer
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15.
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A
group of igneous rocks are found. The rocks all have very low silica contents. Based on this
characteristic alone, to what group of igneous rocks do these rocks likely belong?
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Compare and contrast each pair of related terms or phrases.
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16.
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intrusive
igneous rock, extrusive igneous rock
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17.
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magma,
lava
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18.
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Which rock
type or feature forms when rapid cooling of magma does not allow its calcium-rich core to react
completely with the magma?
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19.
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What is
partial melting? Explain how partial melting affects igneous rock formation.
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20.
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What is
fractional crystallization? Does it add or remove elements from magma? Explain your
answer.
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21.
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Why would
crystals formed early in magma crystallization have larger, better-shaped crystals than those that
formed later?
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The diagram
shows the proportions of minerals in common igneous rocks. Use the diagram to answer the following
questions.
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22.
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What four
groups of igneous rocks are shown in the diagram?
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23.
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What
categories of rock grain are shown on the diagram?
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24.
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Rock Sample
A is coarse-grained, 90 percent olivine, and 10 percent pyroxene. What is the name of the rock? What
group is it in?
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Problem
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25.
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According to the diagram below, what elements are removed from this particular magma
during fractional crystallization? What effect does this have on the overall proportions of the
remaining elements—Al, Ca, Si, O, Na, and K—in the magma?
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