Deck 7: Metamorphism: a Process of Change

Question 1

Spreading peanut butter on bread is an application of ____________.

A) compression
B) shear stress

Answer 1

B

Question 2

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

Answer 2

C

Question 3

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

Answer 3

False

Question 4

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 5

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

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

Question 6

A primary difference between phyllite and schist is ____________.

A) schist contains mica, but phyllite contains only clay
B) phyllite contains mica, but 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 7

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

Question 8

A buried body of shale is subjected to differential stress at temperatures greater than 200ºC,causing clay minerals to grow in preferred orientation and producing slate.This is an example of ____________.

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

Question 9

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 10

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

A) compression
B) shear stress

Question 11

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 12

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 13

Clay minerals within a buried body of shale are recrystallized at 400ºC and high pressure to form mica,producing a rock called phyllite; this is an example of ____________.

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

Question 14

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

Question 15

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 16

Two common metamorphic rocks that typically lack foliation are ____________.

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

Question 17

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 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

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 20

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 21

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 22

The region of thermally metamorphosed rock surrounding a cooled pluton is called a(n)____________.

A) shear zone
B) aureole
C) oriole
D) oleo

Question 23

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

A) foliation
B) metasomatism
C) anachronism

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

Which type of metamorphism affects the greatest volumes of rock?

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

Question 26

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 27

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 28

Phyllite 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 depth within the mid-ocean ridge system
D) within a meteorite impact crater

Question 29

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 30

As compared to the amphibolite metamorphic facies,the greenschist facies ____________.

A) consists of lower-grade rocks
B) consists 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 31

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 32

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 33

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 34

Dynamothermal 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 35

Metamorphism,in broadest terms,involves ____________.

A) the settling of crystals within 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

Question 36

Thermal (contact)metamorphism occurs ____________.

A) in areas surrounding igneous intrusions
B) only where gneiss is in contact with schist
C) as 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 37

Foliated metamorphic rocks possess ____________.

A) leafy plant fossils (ancient foliage)
B) a homogeneous 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 38

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 39

Gneiss typically forms under higher pressures than hornfels.

Question 40

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 41

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

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

Question 42

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 43

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

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

Question 44

Burial metamorphism produces ____________.

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

Question 45

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

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

Question 46

Dynamothermal metamorphism produces ____________.

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

Question 47

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

Question 48

The preexisting rock which is subsequently altered to form a metamorphic rock is termed a ____________.

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

Question 49

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

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

Question 50

Thermal (contact)metamorphism produces ____________.

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