Deck 7: Metamorphism: A Process of Change

Question 1

The figure below shows the application of ________.

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

Answer 1

D

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 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

Answer 3

D

Question 4

Metamorphism occurs at temperatures between ________ and ________.

A)diagenesis;lithification
B)diagenesis;melting
C)magmatism;sedimentation
D)melting;pressure solution

Question 5

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

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

Question 6

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 7

Foliation is the alignment of ________ in a metamorphic rock.

A)minerals
B)strata
C)stress
D)facies

Question 8

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 9

Clay minerals within a slate are changed into mica minerals due to the application of heat to a rock.This is an example of ________

A)pressure solution
B)neocrystallization
C)plastic deformation
D)phase change

Question 10

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 11

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

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

Question 12

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

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

Question 13

The image below shows ________.

A)foliation
B)migmatites
C)pressure solution
D)metasomatism

Question 14

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 15

Preferential stress will cause crystals to rotate into a preferred orientation unless the crystals are ________.

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

Question 16

Spreading peanut butter on bread is an application of ________.

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

Question 17

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

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

Question 18

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 19

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 20

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 21

What was the direction of compression that formed the foliation in the image below?

A)top and bottom,pressing inward
B)both sides,pressing inward
C)top and bottom,pulling outward
D)in and out of the image,pulling outward

Question 22

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 23

If mineral grains have been smeared out,the rock was subjected to ________.

A)shear
B)compression
C)tension
D)extension

Question 24

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 25

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 26

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 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

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 29

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

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

Question 30

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 31

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 32

The rock hornfel is often formed due to ________ metamorphism.

A)dynamothermal
B)hydrothermal
C)dynamic
D)thermal

Question 33

Rocks subjected to ________ feel a squeezing motion.

A)metasomatism
B)diagenesis
C)compression
D)extension

Question 34

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

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

Question 35

Heating up a rock causes the atoms in the rock to vibrate and break their bonds.The atoms can then move slightly and create new bonds with nearby atoms.This process is called ________.

A)preferred orientation
B)solid-state diffusion
C)plastic deformation
D)melting

Question 36

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 37

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

A)shear zone
B)aureole
C)chilled margin
D)metamorphic ring

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

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

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

Question 40

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 41

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

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

Question 42

Metamorphic grade describes the intensity or degree of metamorphism.The metamorphic grade of a rock is determined mainly by the temperature and amount of recrystallization or neocrystallization to which a rock is subjected.List the following rocks in order from low-grade to high-grade metamorphic rocks and then describe the changes seen in the suite of rocks as the grade is increased: gneiss,slate,schist,phyllite,and migmatite.

Question 43

Nonfoliated metamorphic rocks are classified based on their ________.

A)metamorphic texture
B)mineral composition
C)percentage of preferred orientation
D)proximity to the metamorphic source

Question 44

Draw the orientation of the preferential stress that created the foliation in the image below.

Question 45

Describe the resulting metamorphism that occurs next to an igneous intrusion.

Question 46

Foliated rock is created by a preferential stress oriented ________ the foliation.

A)the same way as
B)diagonally to
C)perpendicular to
D)parallel to

Question 47

During dynamothermal metamorphism several metamorphic processes are at work.Describe these processes and what effect they might have on the rocks subjected to metamorphism.

Question 48

Which of the following processes is NOT involved directly with the creation of foliation?

A)recrystallization
B)preferential stress
C)compression
D)shear stress

Question 49

A geologist finds a nonfoliated metamorphic rock that is composed entirely of calcite.What is the name of the rock?

A)hornfels
B)slate
C)quartzite
D)marble

Question 50

Which of the following is a high-grade metamorphic rock?

A)quartzite
B)slate
C)gneiss
D)schist

Question 51

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 52

Geologists classify metamorphic rocks according to ________.

A)whether they are foliated
B)whether they contain pseudomorphs
C)the percentage of silica
D)the size of their crystals

Question 53

Metamorphism includes a solid-state change in a rock due to heat,pressure,and/or hydrothermal fluids.Explain what is meant by solid-state change.

Question 54

________ is a common foliated metamorphic rock.

A)Marble
B)Gneiss
C)Hornfel
D)Diorite

Question 55

Which of the following images is of a foliated metamorphic rock?

A)A
B)B
C)C
D)D