Deck 8: Metamorphism and Metamorphic Rocks

Question 1

Because large intrusions, such as batholiths, have such a large surface area they cool quickly and only a relatively small area of surrounding rock undergoes metamorphism.

Answer 1

False

Question 2

Minerals such as mica, quartz, and feldspar ____.

A)can occur only as igneous rocks
B)can occur only as metamorphic rocks
C)can occur as both igneous and metamorphic rocks
D)are useful index minerals for metamorphic rocks that formed from clay-rich rocks
E)all have the same chemical formula

Answer 2

can occur as both igneous and metamorphic rocks

Question 3

Metamorphic rocks ____.

A)always have igneous parent rock
B)always have sedimentary parent rock
C)are the oldest rock on Earth
D)are formed under conditions of high temperatures and pressures
E)can form on Earth's surface under special conditions

Answer 3

are formed under conditions of high temperatures and pressures

Question 4

Contact metamorphism along sills and dikes may produce metamorphosed zones many kilometers wide.

Question 5

Metamorphic rocks are very common in the crystalline basement rocks of shields.

Question 6

Migmatites can form in the deeper portions of the crust at convergent plate boundaries.

Question 7

Differential pressure ____.

A)produces similar features to lithostatic pressure but is a much longer process
B)is always rotational
C)cannot occur at the same time as lithostatic pressure
D)is less transformational than lithostatic pressure
E)typically occurs when two plates collide

Question 8

Gneiss is a high-grade metamorphic rock that is streaked or has segregated bands of light and dark minerals.

Question 9

Various colors of slate result from differing intensities of deformation.

Question 10

During metamorphism, the original rock undergoes changes ____.

A)that result in instability
B)that soften the rock
C)but its former identity is always easily recognizable
D)to achieve equilibrium with its new environment
E)and is always pushed deeper into Earth due to tremendous pressure

Question 11

The two most familiar and widely used metamorphic rocks are marble and slate.

Question 12

Regional metamorphism is confined to convergent plate margins.

Question 13

Shields are ____.

A)composed of igneous, sedimentary, and metamorphic rocks
B)composed of sedimentary and metamorphic rocks
C)composed of limestone and quartz
D)regions of the continents where basement rocks are widely exposed
E)regions of the continents where basement rocks are deeply buried

Question 14

Metamorphism takes place ____.

A)as country rock is melted by contact with magma
B)while rocks remain solid
C)without high temperatures as long as rocks are buried at great depth
D)without high pressure, as long as high temperatures are present
E)only with fluid activity

Question 15

The changes that occur during metamorphosis of a rock can change its texture but will never form new minerals.

Question 16

Slate is a very fine-grained foliated metamorphic rock that commonly exhibits cleavage.

Question 17

The degree of metamorphic change within an aureole ____.

A)is always sharp and well-defined
B)is not dependent on the temperature of the intruding magma
C)is defined by an isograd
D)increases with distance from the intrusion
E)decreases with distance from the intrusion

Question 18

Regional metamorphism ____.

A)is confined only to convergent margins
B)occurs over a large area
C)occurs in shallow areas of Earth's crust
D)is difficult to see along convergent plate boundaries
E)usually has no gradation in metamorphic intensity from one area to another

Question 19

The Taj Mahal in India is constructed mostly of ____.

A)marble
B)slate
C)basalt
D)limestone
E)granite

Question 20

Contact metamorphism ____.

A)is principally the result of high differential pressures
B)produces basalt and gabbro
C)is associated with mountain-building episodes
D)is also known as thermal metamorphism
E)occurs within a large area

Question 21

Which list of foliated rock types is arranged correctly according to increasing coarseness of texture?

A)slate, phyllite, gneiss, schist
B)slate, amphibolite, schist, phyllite
C)schist, phyllite, gneiss, slate
D)slate, phyllite, schist, gneiss
E)schist, phyllite, amphibolite, gneiss

Question 22

Although metamorphism is associated with all three types of plate boundaries, it is ____.

A)most common along convergent plate margins
B)rare along convergent plate margins
C)most common along divergent plate margins
D)difficult to identify metamorphic rock that forms along divergent plate margins
E)coincidental that this association occurs

Question 23

A group of metamorphic rocks that formed under broadly similar temperature and pressure conditions is a(n)____.

A)metamorphic zone
B)isograd
C)metamorphic facies
D)contact zone
E)profile

Question 24

Many ore deposits result from contact metamorphism during which hot, ion-rich fluids ____.

A)migrate from surrounding rock into igneous intrusions
B)migrate from igneous intrusions into the surrounding rock
C)melt the surrounding rock which precipitates the ore
D)reach Earth's surface forming ore deposits as they move
E)become electrically neutral and react chemically with the surrounding rock

Question 25

Two characteristics that have made asbestos and important industrial mineral are ____ and ____.

A)flexibility; fire resistance
B)flexibility; combustibility
C)durability; combustibility
D)elasticity; fire resistance
E)elasticity; combustibility

Question 26

Intensity of regional metamorphism may be recognized by the index ____.

A)crystals
B)fossils
C)minerals
D)ores
E)rocks

Question 27

The rock type that is the source of most commercial asbestos is ____.

A)serpentine
B)amphibole
C)pegmatite
D)hematite
E)biotite

Question 28

The region between two adjacent isograds ____.

A)does not vary in width within a given metamorphic formation
B)is always nonfoliated rock
C)is composed of non-metamorphosed rock
D)makes up a single metamorphic zone
E)is where rock types change

Question 29

What is a metamorphic rock with more than 50% platy and elongated minerals, all of which are large enough to be clearly visible?

A)phyllite
B)gneiss
C)slate
D)schist
E)shale

Question 30

Reaction of country rock with solutions from a cooling magma is known as ____ alteration.

A)geostatic
B)geohydrous
C)geothermal
D)hydrothermal
E)hydrostatic

Question 31

Marble is ____.

A)an extremely hard rock
B)the result of dynamic metamorphism
C)metamorphosed limestone or dolostone
D)rarely used for building
E)metamorphosed quartz

Question 32

Blueschist facies indicate ____.

A)formation at high temperature and pressure
B)evidence of an ancient subduction zone
C)migmatite melting in a subduction zone
D)gneiss formation nearby
E)rock that is a very good heat conductor

Question 33

Two economically important metamorphic minerals are graphite and corundum, which can be used, respectively, for ____.

A)abrasives and furnace linings
B)furnace linings and abrasives
C)furnace linings and dry lubricants
D)dry lubricants and abrasives
E)dry lubricants and talcum powder

Question 34

Minerals in a metamorphic rock that are arranged in an elongated parallel manner indicate that the rock was exposed to ____.

A)water seeping through the rock in one direction
B)the north\south magnetic poles
C)the greater force of gravity closer to Earth's center
D)pressure applied to two sides
E)pressure applied equally to all sides

Question 35

Initial temperature, the size of the intrusion, the fluid content of the magma, and the nature of the country rock are important factors in ____ metamorphism.

A)fault
B)contact
C)divergent
D)convergent
E)conductive

Question 36

An example of a nonfoliated metamorphic rock is ____.

A)hornfels
B)migmatite
C)amphibolite
D)gneiss
E)schist

Question 37

The concept of metamorphic facies ____.

A)cannot be used in areas where the original rocks were clay-rich
B)cannot be used in areas where the original rocks were pure quartz sandstone
C)was developed in Italy in the 1600s
D)is not as useful as the concept of metamorphic zones
E)relies on finding a single index mineral in a particular zone

Question 38

Migmatite ____.

A)is produced during the lower temperature range of metamorphism
B)is a nonfoliated rock
C)never occurs due to regional metamorphism
D)always shows rotational metamorphism
E)has both igneous and metamorphic characteristics

Question 39

Divergent plate boundaries are characterized by ____.

A)contact metamorphism only
B)regional metamorphism only
C)dynamic metamorphism only
D)dynamic and contact metamorphism
E)dynamic and regional metamorphism

Question 40

Foliation indicates that ____ during metamorphism

A)a liquid intrusion flattened crystal patterns
B)magnetic influences were present
C)the rock was subjected to heat and differential pressure
D)the rock was formed deeper in Earth than its nonfoliated counterpart
E)carbon dioxide invaded pore spaces

Question 41

Why is time important in metamorphism?

Question 42

The minerals andalusite, sillimanite, and kyanite all have the chemical formula, Al₂SiO₅. Explain how three different minerals can have the same chemical components and why this fact is important.

Question 43

The three (3)principal agents of metamorphism are heat, ____________________, and ____________________.

Question 44

Explain the significance of metamorphism taking place below the melting temperature of a rock.

Question 45

Heat involved in the metamorphic process may come from lava, ____________________ in the crust, or ____________________.

Question 46

Concentric zones surrounding an igneous intrusion in which contact metamorphism has taken place are called ____________________.

Question 47

The accompanying figure represents the metamorphic grade of shale. Explain the figure in terms of changes in mineral assemblage with increasing metamorphism.

Question 48

Many ore deposits, including copper, lead, iron, and zinc, are associated with ____________________ metamorphism.

Question 49

What two fluid molecules are common in the formation of metamorphic rock? How do they affect the rate of metamorphism and why?

Question 50

Marble, quartzite, greenstone, hornfels, and anthracite are examples of ____________________ metamorphic rocks.

Question 51

____________________ is a general term applied to any silicate mineral that easily separates into flexible fibers.

Question 52

When an oceanic plate collides with a continental plate, what is the metamorphic result?

Question 53

When the locations of the first appearances of a particular index mineral are connected on a map, the result is a line of equal metamorphic intensity called a(n)____________________.

Question 54

What is a metamorphic facies? How is each facies named?

Question 55

A rock that has both igneous and metamorphic characteristics is called ____________________.

Question 56

For purposes of classification, metamorphic rocks are commonly divided into two groups based on their texture: ____________________ and ____________________.

Question 57

Rocks undergo ____________________ , which means that the stress on a rock in Earth's crust is the same in all directions.

Question 58

What are the three (3)types of metamorphism? Where and under what conditions does each occur?