Deck 8: Metamorphism and Metamorphic Rocks

Question 1

What physical properties have made asbestos an important industrial mineral?

Answer 1

noncombustibility and flexibility of the fibers

Question 2

What are some important types of ore deposits that may have resulted from movement of metallic ions in hydrothermal solutions?

Answer 2

copper,gold,iron ores,tin,zinc

Question 3

How does lithostatic pressure differ from differential pressure?

Answer 3

Lithostatic pressure is equal in all directions; differential pressure is not.

Question 4

Metamorphism can be caused by increased temperatures.How can temperatures be raised,geologically,to bring about metamorphism?

Question 5

List some of the minerals commonly used as index minerals for metamorphic zones.

Question 6

How do metamorphic processes form ore deposits? What are some of the ores that are formed?

Question 7

What is the difference between slate and phyllite?

Question 8

Name five of the more than 3,000 uses for asbestos.

Question 9

What does increasing grade of metamorphism mean in terms of the conditions which produced a sequence of metamorphic rocks?

Question 10

Why might the health hazard of asbestos be less widespread than previously believed?

Question 11

What are three possible sources of water and other fluids that are active in metamorphism?

Question 12

Asbestos has been linked to lung cancer,yet why would removing all asbestos from all buildings be a bad idea?

Question 13

What are some uses of metamorphic rocks such as marble,slate,sulfide ore,talc,graphite,and clay?

Question 14

What is the significance of foliation in a metamorphic rock? (Not what is foliation,but what does it mean in terms of the rock's history?

Question 15

Why is time important in metamorphism?

Question 16

Foliated metamorphic rocks are further classified on the basis of what observable properties?

Question 17

What are some examples of nonfoliated metamorphic rocks?

Question 18

Why is heat an important agent of metamorphism?

Question 19

Why is crocidolite asbestos harmful to lungs but chrysotile is not?

Question 20

Some of the oldest known rocks,which have been dated at 3.96 billion years,are metamorphic.What does this tell us about the age of Earth?

Question 21

Slate,phyllite,schist,gneiss,amphibolite,and migmatite are examples of _______ metamorphic rocks.

Question 22

What are two different types of pressures to which rocks can be subjected and can cause metamorphism? ____________________ ____________________,

Question 23

The most important fluid promoting metamorphism is ____________________.

Question 24

The type of metamorphism that occurs over large areas,commonly at convergent plate margins,and is responsible for the production of most metamorphic rocks is ____________________.

Question 25

A rock that has both igneous and metamorphic characteristics is called _______.These rocks form as the result of _______ temperatures.

Question 26

Contact metamorphism is found at the boundary between country rock and _______.

Question 27

What is a metamorphic zone?

Question 28

Many ore deposits,including tin and tungsten,are associated with ____________________ metamorphism.

Question 29

The type of metamorphism that typically produces the hard,dense,fine-grained rocks called mylonites is called ____________________.

Question 30

Name five metamorphic rocks or minerals for which there is an economic use.Name that use.

Question 31

Metamorphism is most common along ____________________ plate boundaries.

Question 32

What is an isograd?

Question 33

The concentric zones surrounding an igneous intrusion,and in which contact metamorphism has taken place,are called ____________________.

Question 34

The type of metamorphism that is common in fault zones in which rocks are subjected to high differential pressures is called ____________________.

Question 35

One plate tectonic process that causes very widespread metamorphism is ____________________.

Question 36

What are some types of ore deposits that have formed in association with contact metamorphism?

Question 37

Metamorphic rocks are commonly divided into these two groups,based on their textures: ____________________ and ____________________.

Question 38

The three types of metamorphism are ____________________,____________________,and ____________________.

Question 39

The region between two _______ makes up a single metamorphic _______.

Question 40

At which type(s)of tectonic plate boundaries does heat sufficient to cause metamorphism occur?

Question 41

What may the intensity of regional metamorphism be recognized by?

A) index of recrystallization
B) index fossils
C) index minerals
D) index polymorphs
E) index cards

Question 42

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

Question 43

Metamorphism takes place ____.

A) in the liquid state, melted by contact with magma
B) in the solid state with or without fluid activity
C) only at great depth
D) in the liquid state, melted by contact with magma, and only at great depth
E) all of these

Question 44

Which of the following correctly lists metamorphic mineral assemblages in order of decreasing temperature/pressure of formation?

A) chlorite, biotite, garnet, staurolite, kyanite, sillimanite
B) biotite, garnet, chlorite, staurolite, sillimanite, kyanite
C) garnet, biotite, chlorite, sillimanite, staurolite, kyanite
D) sillimanite, staurolite, kyanite, garnet, biotite, chlorite
E) sillimanite, garnet, kyanite, staurolite, biotite, chlorite

Question 45

Blueschist facies indicate

A) formation at high temperature and high pressure.
B) evidence of an ancient subduction zone.
C) migmatite melting in a subduction zone.
D) all of these

Question 46

When minerals in a metamorphic rock are arranged in a parallel manner this means that the rock was exposed to

A) pressure perpendicular to the mineral alignment.
B) pressure parallel to the mineral alignment.
C) pressure coming equally from all sides.
D) pressure perpendicular and parallel to the mineral alignment.

Question 47

A metamorphic rock with more than 50% platy and elongated minerals,all of which are visible to the naked eye is a

A) phyllite.
B) gneiss.
C) slate.
D) schist.

Question 48

Metamorphic rocks are those that ____.

A) are claimed to have certain metaphysical properties (e.g., quartz crystals)
B) have different mineral compositions due to increased temperature and pressure
C) have textures due to water and volatile magmatic fluids
D) have different chemical compositions due to organisms and sediments
E) have different mineral compositions due to increased temperature and pressure AND have textures due to water and volatile magmatic fluids

Question 49

Marble is

A) an extremely hard rock.
B) the result of dynamic metamorphism.
C) metamorphosed limestone or dolostone.
D) an extremely hard rock AND metamorphosed limestone or dolostone.

Question 50

Why is asbestos considered a health hazard?

A) The fibers can cause lung cancer.
B) Smoke from burning asbestos can cause lung cancer.
C) Particles are toxic when ingested.
D) Asbestos mining is hazardous for the miners.

Question 51

Metamorphism is a physical and chemical change that occurs in such a way that ____.

A) disequilibrium is reached with the new physical and chemical environment
B) a dynamic equilibrium is reached
C) equilibrium with the new environment is disturbed
D) the rock reaches equilibrium with its new environment
E) the rock's chemistry and texture become increasingly unstable

Question 52

An example of a region where mylonites are formed is ____.

A) the Cascade Range
B) the mid-oceanic ridges
C) the San Andreas Fault Zone
D) the Valles Marianas Rift Zone
E) the Mendocino Fracture Zone

Question 53

What is the reaction of country rock with solutions from a cooling magma known as?

A) hydrothermal solution
B) hydroxide alteration
C) geothermal alteration
D) hydrothermal alteration
E) hydrostatic alteration

Question 54

Which of the following lists of foliated rock types is arranged 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 55

A group of metamorphic rocks that formed under the same broad conditions of temperature and pressure is a

A) metamorphic zone.
B) isograd.
C) metamorphic facies.
D) contact zone.

Question 56

Which mineral group is the source of most commercial asbestos?

A) serpentine
B) amphibole
C) chrysotile
D) serpentine and amphibolite

Question 57

Divergent plate boundaries are characterized by ____.

A) hydrothermal alteration and contact metamorphism
B) regional and contact metamorphism
C) regional and dynamic metamorphism
D) dynamic and contact metamorphism
E) hydrothermal alteration and dynamic metamorphism

Question 58

What are the two most important sources of heat for metamorphism?

A) intrusive magma bodies and deep burial
B) intrusive magma bodies and heat from the core
C) deep burial and volcanism
D) radioactive decay and volcanism
E) radioactive decay and deep burial

Question 59

Kyanite,andalusite,and sillimanite ____.

A) are index minerals formed from clay-rich parent rocks
B) form from the same parent rocks under different combinations of pressure and temperature
C) can transform from one to the other depending on changes in temperature and pressure
D) have the same chemical composition
E) all of these

Question 60

Metamorphic rocks are most common in the flat-lying rocks overlying the stable shields of continents.

Question 61

Granulites are low temperature but high pressure metamorphic facies.

Question 62

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

Question 63

Only magmatic fluids,not pore fluids of the country rock,have an effect on contact metamorphism.

Question 64

Aureoles surrounding felsic bodies will contain higher temperature metamorphic minerals than will mafic magmas.

Question 65

Migmatites can form at convergent plate boundaries.

Question 66

The temperature of the intrusive magma has little effect on the metamorphic minerals formed.

Question 67

The various colors of slate result from differing intensities of deformation.

Question 68

Metamorphic rocks can indicate the chemical changes that have occurred at various depths.

Question 69

Metamorphic rocks have formed throughout all geological periods.

Question 70

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

Question 71

Metamorphic rocks indicate that an even older parent rock once existed in that place.

Question 72

Isograds separate different metamorphic zones.

Question 73

A greenstone is a metamorphosed clay-rich sedimentary rock.