Igneous Rocks
Practice Test
1.
What is the source of heat inside Earth that melts rocks into magma?
SC.D.1.4.2
a.
geothermal energy
b.
Earth's core is hotter for no reason.
c.
the decay of radioactive elements
d.
other molten rocks
2.
Peridotite and dunite have __________ compositions.
SC.D.1.4.2
a.
felsic
b.
ultramafic
c.
intermediate
d.
mafic
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.
partial melting
c.
plate tectonics
d.
melting points
4.
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
5.
An igneous rock with two distinct grain sizes has a __________ texture.
SC.D.1.4.2
a.
coarse-grained
b.
felsic
c.
fine-grained
d.
porphyritic
6.
What extrusive igneous rock has a mafic composition and a glassy texture?
SC.D.1.4.2
a.
diorite
b.
basaltic glass
c.
gabbro
d.
obsidian
