Deck 8: Metamorphism: a Process of Change

Question 1

Clay minerals within a buried body of slate are recrystallized at high temperatures and pressures to form mica,producing a rock called phyllite.This is an example of ________.

A)diagenesis
B)erosion
C)metamorphism
D)weathering

Answer 1

C

Question 2

Broadly,metamorphism involves ________.

A)the settling of crystals in a melt as it cools
B)the sorting of grains by size,as accomplished by rivers and beach waves
C)the cementation of loose grains and the precipitation of new minerals into pore spaces
D)changes in mineralogy and texture in response to heat and stress

Answer 2

D

Question 3

The net chemical change in metamorphic rock induced by a reaction with hot groundwater is termed ________.

A)foliation
B)metasomatism
C)anachronism
D)hydrosomatism

Answer 3

B

Question 4

A buried body of shale is subjected to differential stress,causing clay minerals to realign and produce slate.This is an example of ________.

A)diagenesis
B)erosion
C)metamorphism
D)weathering

Question 5

Which of the following processes CANNOT induce metamorphism?

A)contact with a hot pluton
B)contact with hydrothermal fluids
C)heat and pressure associated with deep burial
D)cementation and compaction of grains during diagenesis

Question 6

A heavy book is placed on top of a ball of pizza dough,causing the dough to flatten.This is an application of ________.

A)normal stress
B)pressure
C)shear stress
D)metasomatism

Question 7

Spreading peanut butter on bread is an application of ________.

A)normal stress
B)pressure
C)shear stress
D)metasomatism

Question 8

Potassium feldspar reacts with water to form clay.This is an example of ________.

A)diagenesis
B)erosion
C)metamorphism
D)weathering

Question 9

Which of the following processes CANNOT occur in the formation of metamorphic rock?

A)the realignment of minerals so that they develop a preferred orientation
B)the segregation of minerals into layers of different compositions
C)the solid-state rearrangement of atoms or ions to create a new assemblage of minerals
D)complete remelting of the rock,followed by solidification to form a new rock

Question 10

Preexisting rock that is subsequently altered to form a metamorphic rock is termed a ________.

A)xenolith
B)source rock
C)protolith
D)phenocryst

Question 11

________ commonly serves as a protolith in the formation of quartzite.

A)Limestone
B)Sandstone
C)Shale
D)Slate

Question 12

The application of ________ during metamorphism causes elongated crystals to align parallel with each other.When this happens,the rock develops ________.

A)pressure;a homogeneous texture
B)differential stress;foliation
C)high temperatures;foliation
D)pressure;foliation

Question 13

The figure below shows the application of ________.

A)tension
B)pressure
C)normal stress
D)shear stress

Question 14

Slaty cleavage,schistosity,and compositional banding are all examples of ________.

A)mineral cleavage
B)foliation
C)recrystallization
D)metamorphic facies

Question 15

________ commonly serves as a protolith in the formation of slate.

A)Limestone
B)Sandstone
C)Shale
D)Basalt

Question 16

Foliated metamorphic rocks possess ________.

A)leafy plant fossils (ancient foliage)
B)a homogeneous texture resulting from randomly oriented grains
C)mineral grains in preferred orientations or patterns of association (banding)
D)minerals precipitated directly from seawater

Question 17

A protolith subjected to metamorphism ________.

A)is always metamorphic rock
B)is always igneous rock
C)is always sedimentary rock
D)may belong to any of the three primary rock types

Question 18

Differential stress will cause crystals to align in a preferred orientation unless the crystals are ________.

A)primarily mica
B)platy
C)equant
D)elongate

Question 19

A pre-existing body of gneiss is subjected to heat and forms a melt.Later,the melt cools and crystallizes to form a(n)________ rock.

A)metamorphic
B)igneous
C)sedimentary
D)metaigneous

Question 20

________ commonly serves as a protolith in the formation of phyllite.

A)Limestone
B)Sandstone
C)Shale
D)Basalt

Question 21

The development of a preferred orientation of large,flaky mica crystals within metamorphic rock is termed ________.

A)slaty cleavage
B)phyllitic luster
C)schistosity
D)compositional banding

Question 22

The blueschist facies is a metamorphic realm of ________.

A)high temperature and pressure
B)low temperature and pressure
C)high temperature but relatively low pressure
D)high pressure but relatively low temperature

Question 23

In the formation of gneiss from granite,distinctive compositional bands form because of ________.

A)crystals migrating within the rock
B)crystals dissolving,with atoms and ions migrating and reorganizing as new crystals
C)crystals melting,with new crystals solidifying in color bands
D)chemical reactions with groundwater

Question 24

Which of the following describes the progression of rock types through increasing metamorphic grade?

A)shale Ò slate Ò phyllite Ò schist
B)basalt Ò andesite Ò rhyolite Ò granite
C)sandstone Ò gneiss Ò hornfels Ò zeolite
D)migmatite Ò slate Ò eclogite Ò schist

Question 25

Regional metamorphism ________.

A)takes place at cool temperatures and low pressure
B)takes place at cool temperatures but high pressure
C)is another name for thermal metamorphism
D)is another name for dynamothermal metamorphism

Question 26

Which of the following statements is NOT true? Hornfels facies ________.

A)are typically nonfoliated.
B)form at high pressures but low temperatures
C)often form as a result of contact metamorphism
D)are often associated with igneous intrusions

Question 27

Which list properly orders metamorphic rocks from lowest grade to highest grade?

A)conglomerate,sandstone,siltstone,and shale
B)shale,slate,phyllite,and quartzite
C)slate,phyllite,schist,and gneiss
D)gneiss,phyllite,schist,and slate

Question 28

What is a primary difference between phyllite and schist?

A)Schist contains mica,whereas phyllite contains only clay.
B)Phyllite contains mica,whereas schist contains only clay.
C)Mica crystals within schist are larger than those within phyllite.
D)Mica crystals within phyllite are larger than those within schist.

Question 29

Consult the figure below.The region of thermally metamorphosed rock surrounding a cooled pluton is called a(n)________.

A)shear zone
B)aureole
C)oriole
D)metamorphic ring

Question 30

Two common metamorphic rocks that typically lack foliation are ________ and ________.

A)slate;phyllite
B)gneiss;migmatite
C)quartzite;marble
D)schist;metaconglomerate

Question 31

Marble and quartzite are nonfoliated rocks because ________.

A)they are never found beneath fault zones or collisional mountain ranges
B)both are dominated by minerals that produce equant grains
C)both are dominated by minerals with crystalline structures that cannot be dissolved
D)dynamothermal metamorphism can break down the structures of their constituent minerals,but neither of these minerals is stable in that metamorphic environment

Question 32

Precambrian metamorphic rocks are exposed at the surface ________.

A)on Mars and Venus but not on Earth
B)at places in continental interiors termed platforms
C)at places in continental interiors termed shields
D)at the bottom of the deep sea

Question 33

A mineral within a metamorphic rock that can be used to provide a narrow constraint on the temperature and pressure of rock formation is termed a(n)________ mineral.

A)thermal
B)index
C)mafic
D)halide

Question 34

The mineral assemblage within metamorphic rock is ________.

A)always identical to that found within its protolith
B)dependent only on the mineral assemblage of its protolith
C)dependent only on the temperature and pressure of formation
D)dependent on both the mineral content of its protolith and the temperature and pressure of formation

Question 35

The process of high-grade metamorphic rocks being altered to form low-grade metamorphic rocks is termed ________ metamorphism.

A)foliated
B)prograde
C)retrograde
D)dynamic

Question 36

________ commonly serves as a protolith in the formation of marble.

A)Limestone
B)Sandstone
C)Shale
D)Gneiss

Question 37

Consult the figure below.Compared with amphibolite metamorphic facies,greenschist facies ________.

A)consist of lower-grade rocks
B)consist of higher-grade rocks
C)involve partially melted rocks
D)have the same grade but a different chemistry due to different protoliths

Question 38

Retrograde metamorphism will not occur unless an increased amount of ________ is added to the system.

A)temperature
B)differential stress
C)pressure
D)water

Question 39

Consult the figure below.Compared with low-grade metamorphic rocks,high-grade rocks ________.

A)always contain more quartz and feldspar
B)are produced close to the surface but high in the stratigraphic column
C)are produced at greater temperatures and pressures
D)are produced at cooler temperatures but greater pressures

Question 40

The process of low-grade metamorphic rocks being altered to form high-grade metamorphic rocks is termed ________ metamorphism.

A)foliated
B)prograde
C)retrograde
D)dynamic

Question 41

Which of the following is NOT part of the process that leads to the exhumation of metamorphic rocks?

A)continents squeezing together
B)mountain belts collapsing
C)erosion
D)rising plumes of magma in the mantle

Question 42

Mylonites,formed from dynamic metamorphism,typically do NOT display ________.

A)foliation roughly parallel to a fault
B)very fine grains
C)shear zones
D)bands of randomly oriented mica grains

Question 43

The rapid,deep burial of sediments in an accretionary prism leads to the formation of a metamorphic rock termed ________.

A)blueschist
B)greenschist
C)migmatite
D)gneiss

Question 44

Thermal (contact)metamorphism produces ________.

A)foliated rocks only
B)nonfoliated rocks only
C)both foliated and nonfoliated rocks
D)Thermal metamorphism does not produce any metamorphic rocks.

Question 45

Consult the figure below.Hot water reacting with the crust is the basis for what type of metamorphism?

A)contact
B)hydrothermal
C)regional
D)shock

Question 46

Within a single mountain range,________.

A)only low-grade metamorphic rocks are likely to be found
B)only high-grade metamorphic rocks are likely to be found
C)only nonfoliated metamorphic rocks are likely to be found
D)it is possible to find a variety of metamorphic rocks produced in distinct facies,including high-,intermediate-,and low-grade rocks

Question 47

Dynamothermal (regional)metamorphism occurs when ________.

A)rock becomes deeply buried during continental collision and mountain building
B)regression of the sea leads to erosion of sedimentary cover on a body of rock
C)the upper surface of a body of rock develops a thick soil profile
D)a pluton causes metamorphism in a small surrounding region

Question 48

Thermal (contact)metamorphism occurs ________.

A)in areas surrounding igneous intrusions
B)only where gneiss is in contact with schist
C)as a consequence of the sinking of a broad region to great depth
D)only at the surface,where rock is in contact with the atmosphere

Question 49

Rocks resulting from thermal (contact)metamorphism will NOT possess ________.

A)a new mineral assemblage distinct from that found prior to intrusion
B)larger crystals than those characterizing the country rock prior to intrusion
C)foliation
D)silicate minerals

Question 50

________ metamorphism affects the greatest volumes of rock and produces the greatest variety in metamorphic rock types.

A)Thermal
B)Dynamothermal
C)Dynamic
D)Shock