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