Deck 8: Metamorphism: A Process of Change

Question 1

Net chemical change in metamorphic rock induced by reaction with hot groundwater is termed ____________.

A)foliation
B)metasomatism
C)anachronism

Answer 1

B

Question 2

Metamorphism,in broadest terms,involves ____________.

A)the settling of crystals in a melt as it cools
B)the sorting of grains by size,as is accomplished by rivers and beach waves
C)cementation of loose grains and 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 preexisting rock that is subsequently altered to form a metamorphic rock is termed a ____________.

A)parent rock
B)source rock
C)protolith
D)premetarock

Answer 3

C

Question 4

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

Question 5

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 6

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 7

A buried body of aragonitic limestone is recrystallized at low temperatures and pressures,producing calcite;this is an example of ____________.

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

Question 8

At the surface,potassium feldspar reacts with water to form clay;this is an example of ____________.

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

Question 9

A primary difference between phyllite and schist is ____________.

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 10

Squashing a fly with a flyswatter is an application of ____________.

A)normal stress
B)shear stress

Question 11

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 12

Foliated metamorphic rocks possess ____________.

A)leafy plant fossils (ancient foliage)
B)a homogenous texture resulting from randomly oriented grains
C)a planar fabric consisting of mineral grains in preferred orientations or preferred patterns of association (banding)
D)minerals precipitated directly from sea water

Question 13

Metamorphism may be induced by ____________.

A)contact with a hot pluton
B)contact with hot groundwater
C)heat and pressure associated with deep burial
D)All of the above are correct.

Question 14

Metamorphism brings changes in mineral arrangement and the texture of rocks,but it never leads to new mineral assemblages.

Question 15

Consult the figure below.Spreading peanut butter on bread is an application of ____________.

A)normal stress
B)shear stress

Question 16

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

A)realignment of minerals so that they develop a preferred orientation
B)segregation of minerals into layers of different compositions
C)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 17

The protolith subjected to metamorphism ____________.

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

Question 18

A body of gneiss is subjected to heat and forms a melt.Later the melt cools and crystallizes to form a(n)____________.

A)metamorphic rock
B)igneous rock
C)sedimentary rock

Question 19

Consult the figure below.Compared to low-grade metamorphic rocks,high-grade rocks ____________.

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

Question 20

All metamorphic rocks are formed within a fairly narrow range of temperature,approximately 400 to 600°C.

Question 21

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

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

Question 22

In the formation of gneiss from granite,the distinctive compositional bands form due to ____________.

A)crystals migrating within the rock
B)crystals dissolving,and atoms and ions migrating and reorganizing as new crystals
C)crystals melting,with new crystals solidifying in color bands
D)the bizarre and seemingly unknowable nature of the blueschist metamorphic facies

Question 23

Precambrian metamorphic rocks are exposed at the surface ____________.

A)on Mars and Venus,but nowhere 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 24

The mineral assemblage within metamorphic rock is ____________.

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

Question 25

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 26

Gneiss typically forms under higher pressures than hornfels.

Question 27

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 28

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

A)thermineral
B)index mineral
C)mafic mineral
D)halide mineral

Question 29

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 30

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 31

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

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

Question 32

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

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

Question 33

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

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

Question 34

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 35

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

A)mineral cleavage
B)foliation
C)recrystallization
D)sedimentary structures

Question 36

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)oleo

Question 37

Consult the figure below.As compared to the amphibolite metamorphic facies,the greenschist facies ____________.

A)consist of lower-grade rocks
B)consist of higher-grade rocks
C)is an identical temperature and pressure regime;greenschists and amphibolites bear different mineral assemblages only because of differences in protolith chemistry

Question 38

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 39

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

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

Question 40

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

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

Question 41

Dynamothermal (regional)metamorphism occurs when ____________.

A)rock becomes buried deeply during continental collision and mountain building
B)regression of the sea leads to erosion of sedimentary cover atop 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 42

Which type of metamorphism affects the greatest volumes of rock?

A)thermal metamorphism
B)dynamothermal metamorphism
C)dynamic metamorphism

Question 43

Dynamothermal (regional)metamorphism produces ____________.

A)foliated rocks only
B)nonfoliated rocks only
C)both foliated and nonfoliated rocks

Question 44

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 45

Mylonites,formed from dynamic metamorphism,typically display ___________.

A)foliation roughly parallel to a fault
B)very fine grains
C)shear zones
D)All of the above are correct.

Question 46

Flattened-clast conglomerate would most likely be found ____________.

A)in an aureole around a cooled igneous intrusion
B)at the eroding base of an ancient collisional mountain range
C)at a depth within the mid-ocean ridge system
D)within a meteorite impact crater

Question 47

Burial metamorphism produces ____________.

A)foliated rocks only
B)nonfoliated rocks only
C)both foliated and nonfoliated rocks

Question 48

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 49

Thermal (contact)metamorphism produces ____________.

A)foliated rocks only
B)nonfoliated rocks only
C)both foliated and nonfoliated rocks

Question 50

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

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

Question 51

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)it is possible to find a variety of metamorphic rocks produced in distinct facies,including high-,low-,and intermediate-grade rocks

Question 52

Meteorite impacts have been known to induce metamorphism of sediments and rocks.

Question 53

Which of the following is part of the process that leads to the exhumation of metamorphic rocks?

A)continents squeezing together
B)mountain belts collapsing
C)erosion
D)All of the above are correct.