Section #: 5.1
What Are Igneous Rocks?
Practice Test
1.
Peridotite and dunite have __________ compositions.
SC.D.1.4.2
a.
mafic
b.
ultramafic
c.
felsic
d.
intermediate
Hint
2.
Igneous rocks that cool on Earth's surface are called __________.
SC.D.1.4.2
a.
lava
b.
molten
c.
intrusive
d.
extrusive
Hint
3.
What process explains why a molten magma often is a mix of molten rock and crystals?
SC.D.1.4.2
a.
Bowen's reaction series
b.
plate tectonics
c.
partial melting
d.
melting points
Hint
4.
Which is not a compositional classification of a magma?
SC.D.1.4.2
a.
andesitic
b.
basaltic
c.
phaneritic
d.
rhyolitic
Hint
5.
What is the temperature change in Earth's crust called?
SC.D.1.4.2
a.
radioactive decay
b.
geothermal gradient
c.
thermal energy
d.
hydrothermal gradient
Hint
6.
Oceanic crust melts at __________ than continental crust.
SC.D.1.4.2
a.
lower temperatures
b.
the same temperature
c.
higher temperatures
d.
higher pressures and lower temperatures
Hint
7.
Extrusive rocks have fine-grained textures because __________.
SC.D.1.4.2
a.
they cooled inside Earth's crust
b.
they cooled quickly
c.
they are derived from volcanoes
d.
they cooled slow
Hint
8.
__________ explains the relationship between cooling magma and mineral formation.
SC.D.1.4.2
a.
Geothermal gradients
b.
Bowen's reaction series
c.
Branches of crystallization
d.
Partial melting
9.
What is the last mineral to form on the left branch of Bowen's reaction series?
SC.D.1.4.2
a.
quartz
b.
olivine
c.
pyroxene
d.
feldspar
10.
What is the source of heat inside Earth that melts rocks into magma?
SC.D.1.4.2
a.
other molten rocks
b.
Earth's core is hotter for no reason.
c.
geothermal energy
d.
the decay of radioactive elements
Hint
11.
What branch of Bowen's reaction series cools with a continuous change in composition?
SC.D.1.4.2
a.
the feldspars
b.
the iron-magnesium groups
c.
the silica chains
d.
the carbonates
12.
Granite is an example of __________ rock.
SC.D.1.4.2
a.
a partially melted
b.
an intrusive igneous
c.
an extrusive igneous
d.
a volcanic ash
13.
What extrusive igneous rock has a mafic composition and a glassy texture?
SC.D.1.4.2
a.
obsidian
b.
basaltic glass
c.
gabbro
d.
diorite
Hint
14.
How are igneous rocks formed?
SC.D.1.4.2
a.
from increased pressures and temperatures
b.
from the cementation of mineral grains
c.
from the compaction of loose sediments
d.
from the crystallization of magma
Hint
