Deck 8: Metamorphism and Metamorphic Rocks

Question 1

Which of the following is not connected or involved with shock metamorphism?

A)mylonites
B)impactiles
C)coesite
D)asteroids

Answer 1

A

Question 2

Graphite is identified in a particular schist. Which one of the following conclusions is justified?

A)The schist formed from a quartz- rich, sedimentary limestone.
B)The rock also contains diamonds; both are crystalline forms of the element carbon.
C)The graphite lubricated shearing movements along a fault, causing a schist to form.
D)The pre- metamorphic rock was a shale or mudstone containing organic matter.

Answer 2

D

Question 3

is typically formed by metamorphism of a sandstone.

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

Answer 3

B

Question 4

is thought to form by partial melting and in situ crystallization of the melted portion.

A)Migmatite
B)Megatite
C)Magnetite
D)Magmatite

Question 5

is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a metamorphic rock.

A)Foliation
B)Marbleizing
C)Stress streaking
D)Rock cleavage

Question 6

What major change occurs during metamorphism of limestone to marble?

A)Calcite grains are dissolved away leaving only marble crystals.
B)Limestone grains react to form quartz and feldspars.
C)Calcite grains grow larger and increase in size.
D)Clays crystallize to micas, forming a highly foliated, mica- rich rock.

Question 7

What platy, parallel, mineral grains are the most visual aspect of foliated metamorphic rocks?

A)feldspars
B)quartz
C)carbonates
D)micas

Question 8

Which of the following forms at the highest grade of regional metamorphism?

A)schist
B)hornfels
C)phyllite
D)slate

Question 9

What is the major source of heat for contact metamorphism?

A)heat from the spontaneous decomposition of micas and feldspars
B)deep burial and heat from the Earth's interior
C)heat from grinding and shearing on faults
D)heat from a nearby magma body

Question 10

is characterized by the segregation of light- and dark- colored minerals into thin layers or bands.

A)Slate
B)Quartzite
C)Garnet hornfels
D)Granitic gneiss

Question 11

Which of the following lists the rocks in the order of increasing grain size and increasing grade of metamorphism?

A)schist, slate, phyllite
B)phyllite, slate, schist
C)slate, phyllite, schist
D)slate, schist, phyllite

Question 12

Which of the following is not necessary for the formation of metamorphic rock?

A)calcium- rich or liquids
B)chemically active liquids
C)heat
D)pressure

Question 13

is a nonfoliated rock formed by contact metamorphism of a shale or mudstone.

A)Hornfels
B)Gneiss
C)Schist
D)Marble

Question 14

Which of the following best describes the conditions of contact metamorphism?

A)Pressures are very high, the rock is deeply buried, and temperatures are raised by the Earth's internal heat.
B)Pressures are fairly low, the rock is in the upper part of the crust, and heat is supplied from a nearby magma body.
C)Depths are fairly shallow, but temperatures and pressures are so high that the rocks begin to partially melt.
D)Heat is generated by shearing and mechanical movements along faults.

Question 15

Which of the following environments would exhibit sheared and mechanically fragmented rocks?

A)regional metamorphism of pyroclastic volcanic rocks
B)intense compression in a deep- seated, regional metamorphic zone
C)fault movements at shallow depths
D)heating of shales and mudstones near a pluton

Question 16

Amphibolite is a foliated metamorphic rock composed principally of hornblende and plagioclase. It forms .

A)by regional metamorphism of volcanic rocks such as basalt
B)by contact metamorphism of sandstone along the contact with a granitic batholith
C)by gouging and crushing of limestone along a fault
D)by the impact of an asteroid on interbedded sandstone and shale

Question 17

What term describes the zone of contact metamorphism surrounding an intrusive magma body?

A)aureole
B)aura
C)auricle
D)oracle

Question 18

Which rock has the finest grain size?

A)phyllite
B)slate
C)marble
D)gneiss

Question 19

Which low- grade metamorphic rock, composed of extremely fine- sized mica and other mineral grains, typically exhibits well- developed rock cleavage?

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

Question 20

During metamorphism, what is the major effect of chemically active fluids?

A)They aid in the movement of dissolved silicate constituents and facilitate growth of the mineral grains.
B)They increase the pressures in deeply buried, regional- metamorphic zones.
C)They prevent partial melting so solid rocks can undergo very high temperature regional metamorphism.
D)They facilitate the formation of schistosity and gneissic banding in hornfels and slates.

Question 21

Which metamorphic rock or rocks exhibit alternating layers or bands of different light- and dark- colored minerals?

Question 22

In which setting would regional metamorphism be most likely?

A)at shallow depths below an oceanic ridge or rift zone
B)at great depths in the crust where two continents are colliding
C)at shallow depths beneath the seafloor where water pressures are immense
D)at shallow depths along major transform faults in the continental crust

Question 23

a. phyllite b. marble c. slate d. schist

Question 24

What foliated, metamorphic rock is texturally intermediate between slate and schist?

A)fault breccia
B)gneiss
C)quartzite
D)phyllite

Question 25

What type of stress (pressure)is illustrated in diagram B above?

Question 26

List the three most important agents of metamorphism.

Question 27

Which type of metamorphism occurs specifically in the heated zone around a pluton or other body of magma?

Question 28

Which of the following statements concerning slate is NOT true?

A)Rock cleavage is common.
B)It forms from shales and mudstones.
C)Sedimentary features may be visible.
D)It has abundant, coarse- grained mica.

Question 29

forms from the metamorphism of limestone or dolostone.

A)Migmatite
B)Quartzite
C)Amphibolite
D)Marble

Question 30

Which metamorphic rock, widely used for monuments and buildings, would deteriorate significantly in contact with acid rain?

Question 31

What type of sedimentary rock is typically metamorphosed to form slates or phyllites?

Question 32

What type of stress (pressure)is illustrated in diagram A above?

Question 33

Is the texture of a metamorphic rock always indicative of the conditions (degree of metamorphism)under which it formed? (Hint: Think about the protolith and how it may influence the resulting metamorphic rock.)

Question 34

Is it always possible to determine the original parent rock (called a protolith)prior to metamorphism? Why or why not? List three protoliths and give a possible metamorphic equivalent for each one.

Question 35

What metamorphic rock forms by intense ductile deformation along fault zones at depth in the Earth?

Question 36

What strongly banded, metamorphic rocks show good evidence for having formed by partial melting?

Question 37

Give the name of a rock formed by regional metamorphism of a conglomerate.

Question 38

Foliation in metamorphic rocks is mainly evident in the parallel alignment of certain mineral grains. What are they?

Question 39

Briefly outline how regional metamorphism is related to plate boundaries. Are certain types of metamorphic rocks indicative of particular plate boundaries or tectonic settings? Give two or three examples of such rocks and indicate the tectonic environment they represent.