Deck 8: Metamorphism and Metamorphic Rocks

Question 1

________ metamorphism tends to occur in regions where massive amounts of sedimentary or volcanic materials accumulate in a subsiding basin, pushing older rocks further into the interior.

A)Contact
B)Hydrothermal
C)Burial
D)Regional

Answer 1

C

Question 2

If clay minerals in a sedimentary rock were buried at a depth where subsurface temperatures exceeded 200°C, which common metamorphic mineral would they become?

A)Quartz
B)Muscovite
C)Amphibole
D)Plagioclase

Answer 2

B

Question 3

Metamorphic rocks can sometimes contain unusually large grains surrounded by a fine-grained matrix of other minerals.These large crystals are called ________.

A)vesicles
B)phenocrysts
C)inclusions
D)porphyroblasts

Answer 3

D

Question 4

Which of the following is the parent rock of quartzite?

A)Limestone
B)Conglomerate
C)Granite
D)Sandstone

Question 5

What kind of force will create foliation in metamorphic rocks?

A)Tension
B)Compression
C)Shear
D)Brittle

Question 6

________ is the process by which new mineral grains larger than the original mineral grains form as a result of metamorphic heat.

A)Recrystallization
B)Foliation
C)Dissolution
D)Metasomatism

Question 7

Which of the following is not an example of foliation?

A)Parallel alignment of flattened mineral grains or pebbles
B)Compositional banding in which the separation of light and dark minerals creates a layered appearance
C)Rock cleavage where rocks can be easily split into tabular slabs
D)Recrystallization of spherical minerals to create layers parallel to the direction of greatest stress

Question 8

In which geologic setting is the most widespread occurrence of hydrothermal metamorphism found?

A)Subduction zones between oceanic and continental plates
B)Along the axis of a mid-ocean ridge system
C)Along transform plate boundaries
D)Where mantle plumes interact with the bottom of continental plates

Question 9

Which style of metamorphism will be generated by a magma pluton?

A)Contact
B)Subduction zone
C)Burial
D)Regional

Question 10

Physical rotation of platy minerals will contribute most to the development of foliation in ________ grade metamorphism.

A)low-
B)medium-
C)medium-high-
D)high-

Question 11

Which of the following rocks represents the highest grade of metamorphism?

A)Biotite schist
B)Quartzite
C)Phyllite
D)Gneiss

Question 12

Which low-grade metamorphic rock displays thin, parallel layers and contains very fine grains of mica?

A)Schist
B)Gneiss
C)Anthracite
D)Slate

Question 13

Which of the following lists of metamorphic rocks places the rocks in order from lowest metamorphic grade to highest?

A)Gneiss, slate, phyllite, schist
B)Anthracite, hornfels, quartzite, marble
C)Slate, phyllite, schist, gneiss
D)Ironstone, sandstone, slate, gneiss

Question 14

Which of the following scenarios best describes the formation of hornfels?

A)Mudstones are metamorphosed by directed pressure.
B)Granite is melted and recrystallized.
C)Shales and mudstones are baked during contact metamorphism.
D)Phyllite is altered by contact with hydrothermal fluids.

Question 15

________ is the process by which a rock changes form or mineral content as a result of environmental changes such as heat and pressure.

A)Rifting
B)Precipitation
C)Metamorphism
D)Foliation

Question 16

What is the definition of metasomatism?

A)The rearrangement of ions already present due to changes in heat
B)The lengthening of mineral crystals due to directed pressure
C)The change in chemical composition because hot fluids are bringing or removing ions
D)The more compact organization of mineral crystals due to confining pressure

Question 17

What is foliation?

A)Intergrown mineral crystals formed from cooling magma
B)Randomly oriented mineral crystals placed due to confining pressure
C)Thin, parallel layers of clay sediments that have been compressed
D)Roughly parallel layers of mineral crystals aligned perpendicular to the direction of pressure

Question 18

Generally speaking, how does the chemical composition of most metamorphic rocks compare to that of the parent rock?

A)Their chemical composition will be nearly the same.
B)In order to be a metamorphic rock, the chemical composition must change by 50 percent.
C)There will be a complete compositional change.
D)Knowing the chemical composition is not necessary to understand metamorphic rocks.

Question 19

What is the definition of a parent rock?

A)The rock that was altered by metamorphism
B)The resulting precipitate when water dissolves mineral matter
C)The rock produced by metamorphism
D)The igneous rock forming through solidification of magma

Question 20

Which of the following is not an environment of metamorphism?

A)Contact with a hot magma body
B)Hot fluids coming off a diaper
C)Slow cooling of a magma
D)High pressure in a subduction zone

Question 21

Which of the following materials is most closely associated with shock metamorphism and meteorite impact sites?

A)Slate
B)Blueschist
C)Gneiss
D)Tektites

Question 22

Metamorphic facies derive their names from those metamorphic rocks specifically formed from a ________ parent.

A)basaltic
B)granitic
C)shale
D)obsidian

Question 23

What is a metamorphic facies?

A)A rock that forms at specific metamorphic conditions and can be used to determine the metamorphic style
B)Textural transitions based on the direction and amount of pressure
C)Zones of contact metamorphism along an intrusive igneous rock
D)An assemblage of minerals that form in very similar metamorphic environments

Question 24

________ are materials that are good indicators of the metamorphic environment in which they formed and can be used to distinguish between various zones of metamorphism.

A)Index fossils
B)Index minerals
C)Blueschists
D)Aureoles

Question 25

Which of the following is a metamorphic facies?

A)Kaolinite
B)Staurolite
C)Eclogite
D)Quartzite

Question 26

Which of the following can be a parent rock for gneiss?

A)Shale
B)Granite
C)Schist and phyllite
D)Marble and shale
E)Shale, granite, schist, and phyllite

Question 27

Why is quartz a bad mineral to use to determine a metamorphic environment?

A)Because it is not common in metamorphic rocks
B)Because silicate minerals do not metamorphose
C)Because quartz is stable over a wide range of metamorphic settings
D)Because it can only be used in hydrothermal metamorphism

Question 28

Can parent rock features such as sedimentary structures and fossils survive low-grade metamorphism?

A)Yes, because the shells of the organisms are strong enough to withstand directed pressure.
B)No, because the sediments and organic materials will be melted.
C)Yes, because such features can withstand low temperatures and pressures but will be destroyed in higher metamorphic grades.
D)No, because even low-grade pressure is too much for such delicate features.

Question 29

________ is a widespread type of metamorphism typically associated with mountain building.

A)Pyrometamorphism
B)Burial metamorphism
C)Shock metamorphism
D)Regional metamorphism

Question 30

What is the source of water for hydrothermal metamorphism?

A)Groundwater percolating from the surface
B)Fluids coming off magma plutons
C)Black smokers sucking seawater into the subsurface
D)Groundwater from the surface and fluids from magma plutons

Question 31

________ can produce intricately folded rocks.

A)Differential stress
B)Confining pressure
C)Heat
D)Hydrothermal fluids
E)Cold surface water

Question 32

A(n)________ facies is associated with a high-pressure, low-temperature environment.

A)zeolite
B)granulite
C)blueschist
D)eclogite

Question 33

Olivine can be converted to spinel through ________.

A)directed pressure
B)heat
C)hydrothermal fluids
D)confining pressure

Question 34

Along which type of tectonic boundary will greenschists and blueschists form?

A)Transform
B)Convergent
C)Divergent
D)Failed rift zone

Question 35

What is the most important factor driving metamorphism?

A)Pressure
B)Heat
C)Hydrothermal fluids
D)Orientation

Question 36

________ metamorphism is responsible for the emplacement of metallic ore veins.

A)Contact
B)Burial
C)Hydrothermal
D)Subduction zone

Question 37

Why will metamorphic rocks found in a contact metamorphism aureole be nonfoliated?

A)Because the main agent of metamorphism is heat, which will result in intergrown crystals
B)Because the pressures involved with contact metamorphism destroy foliated crystals
C)Because the temperatures associated with this are too low to alter the rock
D)Because the velocity of the hydrothermal fluids will carry foliated materials away

Question 38

Which tectonic boundary is associated with regional metamorphism?

A)Convergent
B)Divergent
C)Dip-slip
D)Transform

Question 39

Which of these mineral assemblages is characteristic of a greenschist facies?

A)Potassium feldspar, biotite, and quartz
B)Chlorite, epidote, and serpentine
C)Hornblende
D)Quartz and muscovite

Question 40

________ metamorphism will occur where two blocks of rock are grinding against each other.

A)Impact
B)Regional
C)Hydrothermal
D)Fault zone

Question 41

What role does heat play in creating new minerals or new crystalline structures in metamorphic rocks?

Question 42

What is gneissic banding, how does it form, and how does it compare to the color banding that is often found in marble?

Question 43

Compare and contrast confining pressure and compressional stress relating to metamorphic rocks.What will happen to the mineral crystals in each situation? Also, provide examples of geologic environments where such pressure would be the main agent of metamorphism.

Question 44

Most metamorphic rocks near the Earth's surface are derived from three common sedimentary rocks.Which three?

A)Conglomerate, graywacke, and arkose
B)Shale, quartz sandstone, and limestone
C)Basalt, travertine, and claystone
D)Quartz sandstone, arkose, and siltstone

Question 45

What is the average increase in temperature along the geothermal gradient in the upper crust?

A)13°C per km
B)25°C per km
C)30°C per km
D)42°C per km

Question 46

Which of the following environments would most likely produce metamorphism in fault zones?

A)Great depth and low temperatures
B)Shallow depth and low temperatures
C)Great depth and high temperatures
D)Shallow depth and high temperatures

Question 47

Compare and contrast how the aureole of contact metamorphism will change in thickness depending on the intrusive igneous structure.

Question 48

What fluid is generally responsible for metasomatism?

A)Sulfuric acid
B)Mixed air
C)Water
D)Petroleum

Question 49

Sedimentary rocks are always the parent rocks for metamorphic rocks.

Question 50

Explain how migmatites form.Why are they difficult to fit into any of the three basic rock types?

Question 51

The geothermal gradient represents a decrease in interior temperature with decreasing distance from the surface.

Question 52

What are the two main categories of metamorphic texture?

A)Heat and pressure
B)Schistosity and dissolution
C)Vesicular and pyroclastic
D)Foliated and nonfoliated

Question 53

Foliated textures are primarily the result of heat.Nonfoliated textures are primarily the result of directed pressure.

Question 54

Define metamorphic grade.

Question 55

________ metamorphism will occur when high-speed projectiles strike the Earth's surface.

A)Fault zone
B)Shock
C)Subduction zone
D)Contact

Question 56

How can a meteorite impact metamorphose a rock? What temperature/pressure conditions will be present?

Question 57

What kind of temperature and pressure conditions will exist in a burial metamorphism environment?

A)Low temperature and low pressure
B)Low temperature and high pressure
C)High temperature and low pressure
D)High temperature and high pressure

Question 58

Metamorphism ends when the rock begins to melt.

Question 59

Name three rocks that are produced by contact metamorphism.

A)Quartzite, marble, and hornfels
B)Marble, schist, and slate
C)Slate, phyllite, and gneiss
D)Gneiss, quartzite, and anthracite coal

Question 60

What kind of temperature and pressure conditions will exist in a subduction zone metamorphic environment?

A)Low temperature and low pressure
B)Low temperature and high pressure
C)High temperature and low pressure
D)High temperature and high pressure

Question 61

Slate and phyllite are similar in appearance.How can the foliation and the shine be used to tell them apart?

Question 62

What is the name of this rock?

A)Slate
B)Quartzite
C)Schist
D)Gneiss

Question 63

What is the name of this rock? (Hint: It can scratch glass.)

A)Slate
B)Quartzite
C)Marble
D)Gneiss

Question 64

What is the parent rock of the metamorphic sample displayed?

A)Limestone
B)Quartz sandstone
C)Shale
D)Granite

Question 65

What kind of metamorphism will occur if the temperature is 800°C and the depth of metamorphism is 7 km?

A)Hydrothermal
B)Contact
C)Regional
D)Subduction zone

Question 66

What are the four agents of metamorphism?

Question 67

What is the temperature range over which hydrothermal metamorphism will occur?

A)0-400°C
B)400-1000°C
C)200-600°C
D)600-750°C

Question 68

Assume that this foliated rock is oriented so that north is at the top of the image.From which compass directions is the greatest differential stress coming?

A)North and south
B)North and east
C)South and west
D)West and east

Question 69

What is the name of the metamorphic rock in the image above?

A)Slate
B)Shale
C)Gneiss
D)Schist

Question 70

What is the minimum depth at which subduction zone metamorphism will occur?

A)0 km
B)30 km
C)25 km
D)13 km

Question 71

What degree of foliation is exhibited by the metamorphic rock in the image above?

A)Schistosity
B)Nonfoliation
C)Gneissic banding
D)Slaty cleavage

Question 72

Which agent of metamorphism was primarily responsible for generating the rock in the image above?

A)Heat
B)Directed pressure
C)Confining pressure
D)Partial melting

Question 73

Marble and quartzite can be similar in appearance.Name two simple ID techniques that can be used to differentiate between the two.

Question 74

Which kind of stress (confining pressure or differential stress)is responsible for creating the texture visible in this rock?

A)Confining pressure
B)Differential stress

Question 75

What is the texture of this rock?

A)Schistosity
B)Nonfoliated
C)Slaty cleavage
D)Gneissic banding

Question 76

What kind of metamorphism will occur if the environmental conditions are 400°C and 5 kilobars?

A)Hydrothermal
B)Contact
C)Regional
D)Subduction zone