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