Deck 7: Metamorphism, Metamorphic Rocks, and Hydrothermal Rocks

Question 1

Metamorphic rock forms from pre-existing rock when heat and pressure cause solid-state transformations.

Answer 1

True

Question 2

Metamorphism includes melting.

Answer 2

False

Question 3

Metamorphic rocks owe their texture mostly to temperature.

Answer 3

False

Question 4

Any new mineral that has crystallized under high-pressure conditions tends to occupy less space than did the mineral or minerals from which it formed.

Question 5

Andalusite, kyanite, and sillimanite are among the best known index minerals that provide information about the temperature and pressure of metamorphism.

Question 6

The original rocks must have been brittle in order for them to bend and mold under stress.

Question 7

Gneissic texture has the minerals separated into distinct (light and dark) layers, or lenses.

Question 8

Minerals that crystallize in needle-like shapes (for example hornblende) grow with their long axis parallel to the plane of foliation.

Question 9

Hot water (or vapor) is the most important fluid involved in metamorphic processes.

Question 10

Schist forms at higher temperatures and pressure than slate.

Question 11

Contact metamorphism occurs adjacent to a pluton when a body of magma intrudes relatively cool country rock.

Question 12

If limestone is metamorphosed at relatively low temperatures and pressures it recrystallizes into marble.

Question 13

Hydrothermal processes are not important along submarine mid-ocean ridges because of the cooling effect of seawater.

Question 14

Differential stress forces constituents of the rock to become parallel to one another.

Question 15

Shearing causes parts of a body to move or slide relative to one another across a plane.

Question 16

Schist is a metamorphic rock characterized by a nonfoliated texture.

Question 17

Meteor craters show an unusual type of metamorphism called shock metamorphism.

Question 18

Confining pressure is pressure applied equally on all surfaces of a substance as a result of burial or submergence.

Question 19

A migmatite forms when a rock partially melts.

Question 20

A metamorphic rock is similar both in mineralogy and texture to its parent rock.

Question 21

____ is the lowest-grade rock in progressive metamorphism.

A) Schist
B) Gneiss
C) Marble
D) Slate
E) Phyllite

Question 22

A _______ is characterized by parallel-orientated minerals, commonly mica.

A) schist
B) gneiss
C) greenstone
D) amphibolite
E) phyllite

Question 23

_______ metamorphism occurs adjacent to a pluton when a body of magma intrudes a relatively cool country rock.

A) Sedimentary
B) Igneous
C) Regional
D) Burial
E) Contact

Question 24

Low grade metamorphism of _____ forms greenschist, with chlorite as the dominant mineral.

A) granite
B) basalt
C) ocean-floor sediments
D) lake sediments
E) limestone

Question 25

___ is pressure applied equally to all surfaces of a substance as a result of burial or submergence.

A) Differential stress
B) Strain
C) Temperature
D) Confining pressure
E) Magnetism

Question 26

The most important factors controlling the characters of metamorphic rocks include ___.

A) composition of the parent rock
B) temperature
C) pressure
D) water
E) All of the choices are correct.

Question 27

The two most common non-foliated metamorphic rocks are _______ and marble.

A) slate
B) gneiss
C) migmatite
D) quartzite
E) phyllite

Question 28

___ metamorphism is the term used for the process in which rocks are altered by hot water.

A) Aqueous
B) Tectonic
C) Burial
D) Hydrothermal
E) Shock

Question 29

Because of the ease with which it can be split into thin flat sheets, this metamorphic rock is used for making chalkboard, pool tables, and roofs.

A) granite
B) marble
C) gneiss
D) slate
E) quartzite

Question 30

_______ forms when a limestone recrystallizes during metamorphism.

A) Marble
B) Gneiss
C) Phyllite
D) Quartzite
E) Coal

Question 31

___ is produced when grains of quartz in sandstone are welded together when the rock is subjected to high temperatures.

A) Limestone
B) Marble
C) Quartzite
D) Monzonite
E) Granite

Question 32

_____ are important economic resources for lead, zinc, gold, silver, tungsten, tin, and mercury.

A) Meteor impact sites
B) Hydrothermal veins
C) Marble
D) Schists
E) Quartzites

Question 33

___ metamorphism takes place at considerable depth underground (generally greater than 5 km).

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

Question 34

__________ forces the constituents of a rock to become parallel to one another.

A) Pressure
B) Differential stress
C) Strain
D) Heat from a nearby pluton
E) Starch

Question 35

In high temperature and pressure metamorphism, if the parent rock is _____ and the dominant mineral is amphibole then the rock is amphibolite.

A) granite
B) basalt
C) ocean-floor sediment
D) lake sediment
E) limestone

Question 36

_____ is metamorphism coupled with the introduction of ions (charged atoms) from an external source.

A) Metasomatism
B) Digitization
C) Intrusion
D) Differentiation
E) Blending

Question 37

___ tends to deform objects into oblong or flattened forms.

A) Differential stress
B) Strain
C) Temperature
D) Pressure
E) Magnetism

Question 38

The deeper a rock is below the Earth's surface ______.

A) the hotter it will be
B) the cooler it will be
C) the cooler it will be except near a pluton or magma chamber
D) has no influence on temperature

Question 39

Metamorphism may involve all of the following except __.

A) formation of new minerals
B) changes in rock texture: grain size, grain shape, foliation, et cetera
C) metasomatism
D) complete melting of the rock
E) recrystallization

Question 40

_______ is a very fine-grained metamorphic rock that splits easily along parallel planes.

A) Slate
B) Sandstone
C) Marble
D) Arkose
E) Gneiss

Question 41

When hot solutions emerge from the ocean floor, submarine hot springs called ________ form.

A) ophiolites
B) geysers
C) hydrothermal vents
D) mud pots
E) fountains

Question 42

_________ is the pressure felt by deeply buried rock.

A) Shear pressure
B) Atmospheric pressure
C) Hydrostatic pressure
D) Lithostatic pressure
E) Differential pressure

Question 43

If the mineral assemblage in metamorphic rocks is the same, they are regarded as having formed under similar pressure and temperature conditions and belong to the same _______.

A) metamorphic rock group
B) metamorphic mineral group
C) metamorphic facies
D) metamorphic temperature/pressure suite
E) metamorphic province

Question 44

The light-color layers within a typical gneiss are formed by __.

A) amphiboles
B) feldspars
C) pyroxenes
D) olivine
E) calcite

Question 45

The differential stress responsible for foliation can take place at _____.

A) the Gutenberg discontinuity
B) hydrothermal locations
C) static plate boundaries
D) ocean-ocean convergent boundaries
E) the continental crust-ocean crust transition zone

Question 46

A migmatite is a mixed ___ rock.

A) metamorphic and igneous
B) metamorphic and pyroclastic
C) metamorphic and sedimentary
D) contact and regional metamorphic
E) contact and hydrothermal metamorphic

Question 47

The most important factor in controlling the final metamorphic product is __.

A) temperature
B) pressure/stress
C) the composition of the pre-existing rock
D) the effect of fluids such as water
E) shock

Question 48

When clay minerals in a shale are subjected to elevated temperature and pressure, they may change in the solid state (that is, without melting) to form platy minerals like ___ that are at equilibrium with the new temperature/pressure conditions.

A) feldspar
B) amphibole
C) mica
D) carbonate
E) pyroxene

Question 49

___ is a fine-grained metamorphic rock whose parent rock was basalt.

A) Mica schist
B) Phyllite
C) Hornfels
D) Garnet schist
E) Gneiss

Question 50

The zone of contact metamorphism (the aureole), ____.

A) extends throughout the surrounding region because rock is such a good conductor of heat
B) is commonly broad, as much as several kilometers wide
C) is commonly rather narrow, from 1 to 100 meters wide
D) is a thin zone, less than 1 meter wide
E) is a very thin zone, no more than a few centimeters in width

Question 51

Shock metamorphism can occur as a result of ______.

A) volcanic eruptions
B) meteor impacts
C) tsunami
D) earthquakes
E) tornadoes

Question 52

A mineral is said to be ____, if after a long time it does not convert to a new mineral.

A) fixed
B) stable
C) invariable
D) crystalline
E) constant

Question 53

Metamorphic rocks are prevalent __.

A) in continental crust in the middle of a plate, far away from any mountains or active faults
B) within volcanoes
C) in the oceanic crust away from the mid-ocean ridge
D) in intensely deformed portions of large mountain ranges, where the continental crust is subjected to high temperatures, pressures, and tectonic stress
E) nowhere on Earth, because regional metamorphism only occurred back when the mountains were forming

Question 54

______ stress is a type of differential stress.

A) Shearing
B) Confining
C) Lithostatic
D) Hydrostatic
E) Atmospheric

Question 55

When a rock is buried to increasing depth it is subject to increasingly greater temperature and pressure and will undergo _____.

A) contact metamorphism
B) prograde metamorphism
C) shock metamorphism
D) retrograde metamorphism
E) hydrothermal metamorphism

Question 56

In some instances a single mineral, a ____, suffices for determination of the pressure and temperature under which a metamorphic rock formed.

A) metamorphic index mineral
B) metamorphic key mineral
C) metamorphic trace mineral
D) metamorphic mica mineral
E) metamorphic pressure-temperature mineral

Question 57

When hot metal-rich solutions contact cold seawater at submarine spreading ridges, _______ are precipitated.

A) carbonate
B) ore minerals
C) oils
D) basalts
E) silicates

Question 58

___ is a metamorphic rock with distinct light and dark layers that formed at high temperatures and pressures.

A) Slate
B) Phyllite
C) Schist
D) Gneiss
E) Greenstone

Question 59

Lines connecting points of equal temperature on maps or cross sections are called __.

A) thermochrons
B) isochrons
C) isohyetal curves
D) isopleths
E) isotherms

Question 60

The major ____ classification of metamorphic rocks divides them into foliated and non-foliated groups.

A) mineral
B) genetic
C) crystal size
D) fabric
E) textural