Igneous Rocks
Practice Test
1.
What is the last mineral to form on the left branch of Bowen's reaction series?
a.
pyroxene
b.
olivine
c.
feldspar
d.
quartz
2.
According to the figure, what types of minerals are ultramafic?
a.
pyroxine and olivine
b.
amphibole and pyronene
c.
feldspar and quartz
d.
feldspar and biotite
3.
An igneous rock with two distinct grain sizes has a __________ texture.
a.
porphyritic
b.
felsic
c.
fine-grained
d.
coarse-grained
4.
What is the source of heat inside Earth that melts rocks into magma?
a.
the decay of radioactive elements
b.
geothermal energy
c.
Earth's core is hotter for no reason.
d.
other molten rocks
5.
Peridotite and dunite have __________ compositions.
a.
ultramafic
b.
mafic
c.
felsic
d.
intermediate
6.
What is the temperature change in Earth's crust called?
a.
geothermal gradient
b.
thermal energy
c.
radioactive decay
d.
hydrothermal gradient
7.
What extrusive igneous rock has a mafic composition and a glassy texture?
a.
basaltic glass
b.
obsidian
c.
gabbro
d.
diorite
8.
According to the figure, what type of rocks can include quartz?
a.
granite
b.
peridotite
c.
basalt
d.
gabbro
9.
According to the map shown in the figure, which area of Earth contains the highest concentrations of quartz and feldspars?
a.
Hawaii
b.
the west coast of the U.S.
c.
North America
d.
the Pacific Ocean
10.
What is an example of an igneous ore deposit?
a.
hydrothermal deposits
b.
placer deposits
c.
metal-rich quartz veins
d.
porphyritic deposits
