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Earth Systems 3209
Sample Test Solutions
Chapters 6 & 7
Name _______________
Multiple Choice. Choose the best answer for the following multiple choice questions. Write
the UPPERCASE letter of the correct answer on the answer sheet on page 4.
1. Which one of the following is NOT an agent of metamorphism?
a) heat
b) chemically active fluids
c) lithification
d) pressure
2. The great majority of rocks exposed at Earth's surface are of which type?
a) igneous rocks
b) metamorphic rocks
c) sedimentary rocks
3. The greatest volume of metamorphic rock is produced during
a) contact metamorphism
b) crystallization
c) weathering
d) lithification
e) regional metamorphism
4. Which one of the following is NOT a common cement found in sedimentary rocks?
a) silica
b) calcite
c) gypsum
d) iron oxide
5. Fossils found in sedimentary rocks can be used to
a) interpret past environments
b) indicate certain periods of time
c) match rocks of the same age that are found at different places
d) all of the above
6. Which one of the following is NOT a detrital sedimentary rock?
a) shale
b) sandstone
c) siltstone
d) limestone
e) conglomerate
7. The surface process that slowly disintegrates and decomposes rock is called
a) erosion
b) exfoliation
c) crystallization
d) weathering
e) metamorphism
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8. The single most characteristic feature of sedimentary rocks are
a) crystals
b) ripple marks
c) mud cracks
d) strata
9. Metamorphic rocks can form from
a) igneous rocks
b) other metamorphic rocks
c) sedimentary rocks
d) all of the above
10. Which one of the following metamorphic rocks has a nonfoliated texture?
a) marble
b) mica schist
c) slate
d) gneiss
11. The term meaning "conversion into rock" is
a) metamorphism
b) ionization
c) weathering
d) crystallization
e) lithification
12. Which one of the following is the metamorphic form of coal?
a) lignite
b) anthracite
c) bituminous
d) peat
13. Detrital sedimentary rocks are subdivided according to
a) particle size
b) the place where they were found
c) color
d) their age
e) hardness
True/False. For the following true/false questions, if a statement is not completely true, mark
it false. Place a T for True and F for False on the answer sheet on page 4.
1. The nonfoliated metamorphic equivalent of limestone is marble.
2. About seventy-five percent of all rock outcrops on the continents are sedimentary.
3. Igneous rocks are the rock type most likely to contain fossils.
4. Igneous rock, when subjected to heat and pressure far below Earth's surface, will change to
sedimentary rock.
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5. Mineral alignment in a metamorphic rock usually gives the rock a foliated texture.
6. Most sediment ultimately comes to rest in the ocean.
7. Separating strata are bedding planes, flat surfaces along which rocks tend to separate or break.
8. Lithification literally means to "change form."
9. Rock salt and rock gypsum form when evaporation causes minerals to precipitate from water.
10. The two major groups of metamorphic rocks are detrital and chemical.
11. The lithification of sediment produces sedimentary rock.
12. The agents of metamorphism include heat, pressure, and chemically active fluids.
13. The mineral sylvite is the primary ingredient of plaster and wallboard.
Word Choice. Complete each of the following statements by selecting the correct response(s).
Write the correct response on the answer sheet on page 4.
1. Detrital sedimentary rocks are primarily classified by particle [size/shape/composition].
2. Coal forms in swamp water that is oxygen-[enriched/deficient], therefore complete decay of the
plant material is [not/always] possible.
3. During low-grade metamorphism, the sedimentary rock shale becomes the metamorphic rock
called [marble/slate].
4. The most important agent of metamorphism is [heat/pressure].
5. Sediment derived indirectly through the life processes of water-dwelling organisms is referred to
as [detrital/chemical/biochemical] material.
6. Iron oxide, silica, and [calcite/olivine] are the most common cements found in sedimentary
rocks.
7. A banded metamorphic rock that contains mostly elongated and granular minerals is called
[schist/gneiss].
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Written Questions: Answer all questions on this paper.
1. List and describe the two main ways in which sedimentary rocks are formed. (See pp. 1-2 Ch. 6
notes & pp. 158-159 text.)
Compaction: As piles of sediments accumulate the layers at the bottom are compacted by the
weight of the overlying layers. The amount of compaction increases as the size of the sediment
decreases.
Cementation: This is the most important process in the creation of sedimentary rock. Over long
periods of time, mineral matter is deposited from water in the spaces between particles. This mineral
matter (e.g.; iron oxide, calcite, quartz) joins the sediments together to form sedimentary rock.
2. Describe the 4 steps in the formation of anthracite coal. (See 6 Ch. 6 notes & pp. 170-172 text.)
For coal to form, large quantities of plant material have to build up in an environment that has little
or no oxygen to prevent the plants from decaying. As successive layers of plant material build up,
peat (not a rock) is formed. As more and more layers are added, compaction occurs to form lignite
coal. As still more layers of plant material are added, the further increase in temperature and
pressure changes lignite into bituminous coal. When bituminous coal is subjected to the even
higher temperature and pressure associated with mountain-building, it is changed to anthracite coal
(a metamorphic rock).
3. Describe the two main types of metamorphism and give an example of a rock produced by each
type of metamorphism. (See pp. 2-3, Ch. 7 notes & pp. 198-202 text.)
Contact Metamorphism: Thermal or contact metamorphism happens when igneous rocks are
intruded or force their way up into the "country rock". Because the igneous rocks are hot (lava or
magma) they heat the surrounding rock and add pressure. In this way, new minerals are formed and
recrystallization takes place. (The surrounding rocks are baked!). The crystals in the baked rock are
not forced to line up, so contact metamorphism typically produces non-foliated rocks. Chemically
active fluids may also produce new rock during contact metamorphism.
Regional Metamorphism: Regional metamorphism is caused by large movements of the Earth's
crust such as during mountain building, creating great pressure and heat on the rocks forming the
crust. The rocks becomes folded over each other, twisted and doubled. These metamorphic rocks
often compose large masses of some of the oldest known rocks - up to 3500 million years old. As
with contact metamorphism, chemically active fluids may also produce new rock during regional
metamorphism.
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Selected Response
1.
2.
3.
4.
5.
6.
7.
___C
___C
___E
___C
___D
___D
___D
8. ___D
9. ___D
10. ___A
11. ___E
12. ___B
13. ___A
True or False
1.
2.
3.
4.
5.
6.
7.
___T
___T
___F
___F
___T
___T
___T
8. ___F
9. ___T
10. ___F
11. ___T
12. ___T
13. ___F
Word Choice
1.
2.
3.
4.
5.
6.
7.
size
deficient
slate
heat
biochemical
calcite
gneiss
not
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