Quiz 2

Question 1

T/F: The bedrock of the Columbia River Plateau in Oregon and Washington are flood basalts associated with a mantle superplume

Answer 1

True

Question 2

T/F: Ore minerals are often sulfides and oxides of metallic elements.

Answer 2

True

Question 3

Silicates…
- are a major component of continental crust.
- are classified on the basis of how the tetrahedrons join and share oxygen atoms.
- have the silicon-oxygen tetrahedron as their structural unit.
- All the possible answers are correct.
- are a huge category of minerals and include the common minerals quartz and feldspar

Answer 3

All the possible answers are correct

Question 4

Bowen’s reaction series…
A. shows that minerals crystallize in a random order, with no particular pattern involved.
B. allows a geologist to predict what minerals will be found in a given igneous rock.
C. is an attempt to explain the logic of formation of sedimentary rocks.
D. explains why some compounds use ionic bonds and others have covalent bonding.

Answer 4

B. allows a geologist to predict what minerals will be found in a given igneous rock.

Question 5

Which of the following volcanic features is NOT related to plate-boundary magmatism?
a. Kilauea, Hawaii
b. Cascade Range of the northwestern United States
c. Andes Mountains, South America
d. Mt. Fujiyama, Japan
e. Aleutian Islands, Alaska

Answer 5

a. Kilauea, Hawaii

Question 6

Pillow Basalts…
a) occur in tabular intrusions called dikes.
b) are composed of felsic lava.
c) are formed by lava quenching in a submarine environment.
d) contain large bulbous crystals called pillows.
e) All the possible answers are correct.

Answer 6

c) are formed by lava quenching in a submarine environment.

Question 7

Identify the FALSE statement. Mafic minerals…
- freeze at a higher temperature than silicic minerals do.
- would be at the top of Bowen’s reaction series, crystallizing first out of the melt.
- form rhyolite and granite.
- are those rich in iron and magnesium.
- form black or dark-gray rocks.

Answer 7

form rhyolite and granite

Question 8

Granite
- logically could be found in a batholith.
- is felsic in composition.
- is a phaneritic rock.
- is the coarse-grained equivalent of rhyolite.
- All the possible answers are correct

Answer 8

All the possible answers are correct.

Question 9

After an explosive volcanic eruption on an island, the surrounding sea is full of light-gray floating rock. What must this rock be?
a. rhyolite
b. pumice
c. obsidian
d. basalt

Answer 9

Pumice

Question 10

An unknown mineral scratches glass, has only average specific gravity, and shows no cleavage but does show conchoidal fracture. Which of the following could it be?
a. quartz
b. talc
c. halite
d. mica

Answer 10

Quartz

Question 11

Identify the FALSE statement. Formation of table salt:
a. is, in mineralogic terms, formation of the halide halite.
b. takes place when a solution has become saturated.
c. is an example of solidification of a melt.
d. needs a seed crystal to begin.
e. results in cubic crystals.

Answer 11

c. is an example of solidification of a melt.

Question 12

Which of the following is NOT a mineral?
a. petroleum (oil), which is a liquid
b. cubic zirconia, which is a synthetic diamond substitute that is not found in nature
c. ice, which is water in the solid state
d. Neither A nor B are minerals; however, C is a mineral.

Answer 12

d. Neither A nor B are minerals; however, C is a mineral.

Question 13

T/F: Yellowstone National Park marks the end of a continental hot-spot track.

Answer 13

True

Question 14

T/F: One often finds purple amethyst/quartz crystals within the cavity of a geode. The crystals are “euhedral”.

Answer 14

True

Question 15

The tendency of a mineral to break and produce smooth, curving shell-shaped surfaces is termed
a. luster
b. cleavage
c. conchoidal fracture
d. streak

Answer 15

c. conchoidal fracture

Question 16

Which pair of minerals listed below are polymorphs?
a) calcite and dolomite
b) quartz and halite
c) graphite and mica
d) diamond and topaz
e) graphite and diamond

Answer 16

e) Graphite and diamond

Question 17

When you scrape a mineral along a ceramic plate to observe the color of its powder, you are checking the physical property known as
a. streak
b. cleavage
c. luster
d. specific gravity

Answer 17

a. Streak

Question 18

A rock has a medium-gray, fine-grained groundmass with large crystals of plagioclase. Which of the following statements about it is FALSE?
A. It could logically be porphyritic andesite.
B. The lava flow that produced it got quenched in ocean water.
C. The plagioclase crystals are called phenocrysts.
D. It began to crystallize at depth from intermediate-composition magma, then rose to the surface and became a lava flow.

Answer 18

B. The lava flow that produced it was quickly quenched in ocean water.

Question 19

T/F: Window glass is not a mineral because it doesn’t have crystal lattice structure.

Answer 19

True

Question 20

Which mineral group composes more than 90% of the minerals of the continental crust?
- oxides
- carbonates
- silicates
- sulfides

Answer 20

Silicates

Question 21

T/F: The mineral bronze is produced when humans melt copper and tin together.

Answer 21

False

Question 22

Solid blocks of wall rock (sometimes called country rock) may…
- All the possible answers are correct.
- melt entirely and thus change the chemical composition of the intruding magma.
- be broken off during a process called stoping.
- be broken off by intruding magma.
- not melt but instead remain as recognizable blocks called xenoliths.

Answer 22

All the possible answers are correct

Question 23

Identify the FALSE statement. Diamonds:
- are brought from the mantle to the surface in magma that hardens into kimberlite
- are brought through the crust in large carrot shaped structures called pegmatites
- of industrial quality are used as abrasives
- that have weathered out of ore bodies can end up in stream gravels
- have been found in south africa, india, northwest canada, and the rocky mountains in the US

Answer 23

are brought through the crust in large carrot-shaped structures called pegmatites.

Question 24

T/F: Gold and copper can both be found as native metals.

Answer 24

True

Question 25

An unknown mineral sample can be scratched by a copper penny and will scratch the penny. It reacts with dilute hydrochloric acid to produce carbon dioxide gas. Which of the following could it be?
a. calcite
b. fluorite
c. talc
d. gypsum
e. none of the above

Answer 25

a. Calcite

Question 26

T/F: The energy of various crystals has been shown by scientists to improve human health.

Answer 26

False

Question 27

A black, fine-grained tabular intrusion between two layers of horizontal sedimentary rock must logically be a
a. basaltic sill
b. granitic sill
c. basaltic dike
d. granitic dike

Answer 27

a. Basaltic sill

Question 28

Calcite is a mineral that can constitute oyster shells, and, in such cases, is an example of which method of mineral formation?
a. solidification of a melt
b. precipitation from a solution
c. solid-state diffusion
d. biomineralization
e. fumerolic mineralization

Answer 28

d. Biomineralization

Question 29

Intrusive igneous rocks
a. are fine-grained because they cooled slowly
b. are volcanic rocks
c. are rocks like basalt, andesite, and rhyolite
d. are never seen by humans because they form and remain deep within the Earth
e. cool slowly and are coarse-grained

Answer 29

e. cool slowly and are coarse-grained.

Question 30

Identify the FALSE statement: Magma moves up toward Earth’s surface…
A. because the weight of overlying rock creates pressure that squeezes it up.
B. more quickly as it cools and therefore becomes less viscous and more dense.
C. because it is less dense than the surrounding rock.
D. slowly, working its way up through cracks and narrow conduits.

Answer 30

B. more quickly as it cools and therefore becomes less viscous and more dense.