Given (a.k.a. `First’) Name(s): ____________________
Family (a.k.a. `Last’) name: ______________________________
ON YOUR PARSCORE: `Bubble’ your name, your student I.D. number, and your multiple-choice answers.
I will keep the Parscore forms.
ON THIS TEST PACKET: Write your name. Circle your multiple-choice answers on this packet, so that you can check them when
we go over the test in class.
I will hand this packet back to you when we go over the test, and you’ll keep it.
Geology 10 Test #1 Practice Version
True/False
Indicate whether the statement is true or false. (2 pts. each)
1. Pillow lava forms when a flow of molten lava erupts underwater, quickly cooling the outer surface of
the molten lava.
2. Mineral crystals grow flat faces, which meet at well-defined angles, because they have random,
disorganzed arrangements of atoms that make them up.
3. It is possible to cause part of the Earth’s upper mantle to partially melt by increasing the pressure on
it, such as happens under a mid-ocean ridge.
4. Igneous rocks form when particles of sediment (sand, mud, etc...) pile up in layers and get compacted
into solid rock.
5. A shield volcano has extremely steep sides due to the very low viscosity of its lava flows.
6. A felsic volcanic rock like rhyolite has the same chemical composition as granite, it just cooled more
slowly than granite did.
7. The Earth formed when a large volume of silicate material was ejected from the newly-formed Sun.
8. Part of the evidence for the orderly arrangments of atoms in minerals is the fact that many minerals
display crystal cleavage, i.e. they break in an `organized’ way.
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Matching (3 pts. each)
For each of the questions below, choose the ONE item from `a’ through `e’ that fits best.
a. Biotite
d. Olivine
b. Amphibole
e. Silicate tetrahedron
c. Quartz
9. A light-colored mineral that’s harder than steel, but which doesn’t exhibit cleavage.
10. An example of a double-chain silicate mineral, with cleavage directions at 56 degrees and 124 degrees
from each other.
11. A mineral in which Fe+2 and Mg+2 ions substitute for each other, producing a black variety and a
green variety.
12. Formed from one silicon atom and four surrounding oxygen atoms
13. A sheet-silicate mica mineral that splits along one cleavage direction
For each of the questions below, choose the item from `a’ through `e’ that fits best.
a. pahoehoe
d. pyroclastic
b. a’a
e. cinder cone
c. caldera
14. A large hill formed of small pieces of jagged vesicular basalt
15. Basalt lava flow with a smooth, `ropy’-looking surface
16. Term for material blasted out of volcanoes during explosive eruptions
17. A large depression in the Earth’s surface formed when a volcano collapses into its partially-emptied
magma chamber
18. A flow of basaltic lava with a rough, jagged surface that would be very hard to walk across
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Multiple Choice - General Knowledge
Choose the ONE best answer and mark it on your Parscore form. (4 pts. each)
19. The volcanic activity that creates about 70% of the Earth’s surface occurs in which of the following
settings?
a. Oceanic island volcanic arcs
b. Continental volcanic arcs
c. Mid-ocean ridges
d. Flood-basalt areas on the continents
20. Which of the following is NOT one of the major groups of rocks?
a. Metamorphic
b. Fossiliferous
c. Sedimentary
d. Igneous
21. What caused the Earth to acquire its compositional layering?
a. Differentiation of the planet due to differences in density
b. Large-scale volcanic activity on the early Earth’s surface
c. Accretion of the planet from smaller bodies called `planetesimals’
d. A giant impact from a Mars-sized planet
22. If a batch of lava erupted from a volcano and cooled too quickly for any crystals to form, which of
these rocks would be the result?
a. Obsidian
b. Gabbro
c. Granite
d. Diorite
23. Imagine that you’re studying a volcanically active area, and you find a dome of volcanic rock that has
steep sides and an irregular, lumpy top. Which of the following types of volcanic rock is it probably
made of?
a. Basalt
b. Diorite
c. Andesite
d. Rhyolite
24. Which of these bodies of igneous rock is likely to be the LARGEST?
a. A dike
b. A pluton
c. A batholith
d. A sill
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25. In a very hard mineral like quartz or diamond, which of these is the most likely explanation for the
hardness?
a. The atoms of which it’s made are harder than other atoms.
b. It is coated with a second, much harder mineral.
c. Atoms are sharing electrons in covalent bonds.
d. Atoms are ionically bonded, as in halite.
26. Why are the Na+1 and Cl-1 ions (in the mineral halite) attracted to each other?
a. They are the same size.
b. They have opposite electric charges.
c. They aren’t actually attracted; they repel each other.
d. They come from the same column on the periodic table.
27. The metal alloy that makes up the core of Earth is ____________ as compared to the rocky
mantle.
a. less dense
b. denser
c. very similar in chemistry and density
d. distinct in chemistry but of very similar density
28. Imagine an underground magma chamber, in which the magma is cooling slowly, forming crystals. If
this mixture of liquid and crystals is suddenly erupted out of a volcano, what will be the most likely
texture of the resulting volcanic rock?
a. Aphanitic
b. Porphyritic
c. Glassy
d. Phaneritic
29. Imagine that you’re studying the side of a mountain in Antarctica, and it’s made of layers of
sedimentary rock. Between two of these layers of sedimentary rock - and parallel to them - is a layer of
igneous rock. A friend of yours claims that it’s a lava flow. Which of the following is another
reasonable possibility?
a. It is a sill that intruded parallel to the layers.
b. It is a dike that intruded parallel to the layers.
c. It is a pluton that intruded parallel to the layers.
d. It is a batholith that intruded parallel to the layers.
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Multiple Choice - Deeper Thought
These questions are just like the other multiple-choice questions, just a little harder. As before, choose the
ONE best answer and mark it on your Parscore form.
(6 pts. each)
30. Let’s say you’re exploring a distant planet, and you discover a new group of silicate minerals - the
*quadruple-chain* silicates. These minerals have two directions of cleavage. What would be a
reasonable guess for the angles between these cleavagees?
a. 90 degrees
b. 56 and 124 degrees
c. 25 and 155 degrees
d. Minerals like this probably won’t have cleavage.
31. Imagine you find an exotic new mineral, made of gallium (Ga) and sulfur (S). You decide to name it
DeAnzium. What would be the most likely chemical formula of DeAnzium?
a. Ga3 S
b. GaS2
c. GaS
d. Ga2 S3
32. Imagine you’re examining a sample of granite by looking at a `thin section’ of it. You see evidence
that the crystals that make up the granite have organized atomic structures, but the crystals don’t look
much like crystals - that is, they don’t have flat faces that meet at well-defined angles. Why is this?
a. The crystals interfered with each other’s growth as they grew larger.
b. These crystals only have a well-organized atomic structure in the innermost part
of each crystal.
c. These crystals formed through very fast cooling, so they couldn’t form
well-defined shapes.
d. These are a special category of crystals that don’t obey the Law of Constancy
of Interfacial Angles.
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33. Imagine that you’re thinking of building a house with a view of a beautiful mountain. After studying
the mountain closely, you discover that it is a volcanic landform like Mt. St. Helens or Mt. Etna. What
will you probably think about building a house in this area, after you make this discovery?
a. Explosive eruptions are not much of a danger, since this mountain is made of
gently-sloping flows of basalt that were erupted quietly.
b. Volcanoes like this are almost all inactive, and so it’s safe to build close to the
mountain.
c. The house had better be built a very long way from the mountain, to be out of
reach of lahars and pyroclastic flows.
d. I don’t need to build a strong roof on this house, since ash falls are not much of
a hazard from this type of volcano.
e. As long as I build on a ridgeline near the mountain, there is little danger from
lahars or pyroclastic flows.
34. You and your friends are watching a TV program about earthquakes. The narrator says that `the
Earth’s crust is divided into about 12 major plates’. Which of the following best describes the main
problem with this statement?
a. The number of plates is actually much larger; there are about 40 major plates.
b. The Earth’s crust is actually divided into only 3 major plates, each of which
covers about the same surface area.
c. It’s actually the Earth’s outer core that’s divided into plates, and this includes
both molten iron-nickel alloy and some mantle material.
d. It’s actually the Earth’s lithosphere that’s divided into plates, this includes the
crust and the uppermost part of the mantle.
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Slide Section
35. (T/F) The lowest layer shown in this diagram is the Earth’s outer core.
36. Which of these is the best description of Layer F in this diagram?
a. It is the crust, which is made of lower-density rock than the mantle.
b. It is the asthenosphere, which is the soft layer upon which the Earth’s tectonic
plates move around.
c. This layer is the Earth’s mantle, which underlies the crust and overlies the core.
d. It is the lithosphere, which is composed of the crust and the uppermost part of
the mantle.
37. Labels X, Y, and Z all indicate the same layer of the Earth. What is the best name for this layer?
a. The lithosphere
b. The continental crust
c. The oceanic crust
d. The asthenosphere
38. If you wanted to go to a place on this diagram where you could see active volcanic eruptions due to
decompression melting of the Earth’s mantle, which spot would be the best choice?
a. Z
b. Point Q, in the Earth’s interior
c. X
d. Y
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39. (T/F) The rock shown in this picture was probably a layer of sedimentary rock, deposited in a
deep-ocean environment.
40. What would be the most likely guess as to the type of rock shown in this picture?
a. Diorite
b. Basalt
c. Gabbro
d. Granite
41. What probably formed the prominent vertical structures that we see in this rock cliff?
a. The formation of long, 6-sided quartz crystals as a batch of magma cooled.
b. Metamorphism of rock, which means altering it by heat and pressure during a
long period of burial deep underground.
c. Shrinkage of lava during cooling
d. The deposition of many layers of sediment over a long period of time
42. Imagine that you went up to this cliff, and closely examined the rock that it’s made of. Each of the
columns turns out to be made of a fine-grained, hard, dark rock, with only a very few crystals visible
here and there. Why aren’t there more crystals visible in this rock?
a. Sedimentary rocks like this very rarely have any crystals in them, because
crystals dissolve in seawater.
b. The lava that became this rock cooled too quickly for large, visible-sized
crystals to form.
c. After the rock formed, the crystals in it evaporated into the Earth’s atmosphere,
because they had originally formed at high temperatures.
d. This is a mass of plutonic rock, which underwent very slow cooling deep
underground.
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43. (T/F) This diagram shows the atomic structure of the `building block’ of the most common class of
minerals in the Earth.
44. In this diagram, what is represented by “L”?
a. A large, negatively-charged anion, like neon (Ne)
b. A small, positively-charge cation, like oxygen (O)
c. A small, positively-charged cation, like silicon (Si)
d. A large, negatively-charged anion, like iron (Fe)
45. If you made a mineral out of a bunch of these “building blocks”, along with some Fe and/or Mg, and if
the structures shown here DIDN’T share any corner atoms, which of these minerals would you probably
have made?
a. A single-chain silicate like pyroxene
b. A sheet silicate like muscovite mica
c. An isolated-tetrahedron silicate like olivine
d. A double-chain silicate like amphibole
46. Imagine that you could take the atom at the center of this structure, and magically make it much
larger. What else would probably have to change about the structure?
a. The cations and anions in the structure would switch places.
b. Fewer “Z” atoms would be needed in order to surround each “L” atom.
c. All of the atoms in the structure would become noble-gas atoms.
d. More “Z” atoms would be needed in order to surround each “L” atom.
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47. (T/F) Judging from the steepness of this volcano’s flanks, it is probably made of many flows of basalt.
48. If you could examine the lava flows which, in part, make up this volcano, what sort of rock would they
probably be?
a. Basalt
b. Andesite
c. Gabbro
d. Granite
49. What do volcanologists call the material forming the grey clouds that are coming out of this volcano?
a. Particles of carbonate minerals
b. Lithospheric plate fragments
c. Volcanic ash
d. Volcanic cinders
50. Imagine that you wanted to make this volcanic eruption LESS explosive. If you could magically cause
one of the following changes to happen, which one would reduce the explosive nature of the eruption?
a. Add more volcanic gas to the ascending lava.
b. Make the ascending lava more viscous.
c. Make the ascending lava encounter a water-bearing layer of rock as it rises
towards the Earth’s surface.
d. Decrease the amount of silica in the lava, and increase the amounts of iron and
magnesium.
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51. (T/F) This rock probably formed by the extremely rapid cooling of lava at the Earth’s surface.
52. Which of these is the most likely description of the history of this igneous rock?
a. It was part of a large magma chamber, but got rapidly erupted and cooled
when the overlying volcano collapsed into the magma chamber.
b. It was once magma deep underground, but while this magma chamber was still
molten, erosion cut into it and exposed the still-molten rock, causing it to cool.
c. It cooled slowly underground, and was later exposed at the Earth’s surface by
erosion.
d. The magma from which it formed rose rapidly to the Earth’s surface, and
erupted as lava, which cooled quickly to form the rock.
53. Let’s say you examined this hand-sized sample closely, and found that the light-colored minerals were
mostly feldspars like plagioclase and orthoclase. Examining the feldspar crystals closely, which of these
things would be true about them?
a. They will fizz if you put dilute hydrochloric acid on them.
b. Their color comes from the abundant iron and magnesium in them.
c. They are good examples of single-chain silicates.
d. They are harder than steel, and thus cannot be scratched with a steel nail.
54. Let’s imagine you could go back in time and examine the tectonic setting where this rock formed.
Imagine this rock formed as part of a continental volcanic arc. At the surface, the arc exhibited many
stratovolcanoes. The magma that formed those stratovolcanoes, as well as the magma that formed this
rock, must have formed by some means or another. Which of these described how the magma probably
formed?
a. Where a continent is starting to pull apart, decompression melting of the mantle
(and, to some extent, the lower continental crust) has triggered partial melting.
b. At a mid-ocean ridge, the reduction in pressure on the rocks below the ridge
caused these rocks to melt more easily, thus generating magma.
c. A plume of hot, solid material rose from deep in the mantle, and decompression
of the plume head generated the magma that formed this rock.
d. A subducting oceanic plate released water, lowering the melting point of the
mantle rocks above it.
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Geology 10
Answer key for Practice Test #1
1
T
21
A
41
C
2
F
22
A
42
B
3
F
23
D
43
T
4
F
24
C
44
C
5
F
25
C
45
C
6
T
26
B
46
D
7
F
27
B
47
F
8
T
28
B
48
B
9
C
29
A
49
C
10
B
30
C
50
D
11
D
31
D
51
F
12
E
32
A
52
C
13
A
33
C
53
D
14
E
34
D
54
D
15
A
35
F
16
D
36
D
17
C
37
B
18
B
38
C
19
C
39
F
20
B
40
B