Volcanic Activity
Practice Test
1.
What type of texture do most plutons have?
a.
fine grained
b.
coarse grained
c.
pegmatitic
d.
intermediate grained
2.
What type of igneous pluton is tabular and parallel to surrounding rock layers?
a.
a sill
b.
a dike
c.
a stock
d.
a batholith
3.
What letter in the figure depicts the possible beginning of a pluton like a stock?
a.
none of the above
b.
C
c.
B
d.
A
4.
__________ is the internal resistance to flow of a liquid.
a.
Viscosity
b.
Weight
c.
Specific gravity
d.
Gravity
5.
Rhyolitic magma has the __________ viscosity, the __________ gas content and the __________ silica content of any type of magma.
a.
highest, lowest, lowest
b.
lowest, highest, highest
c.
highest, highest, highest
d.
lowest, lowest, lowest
6.
A __________ is a mushroom-shaped pluton with a round top and flat bottom.
a.
batholith
b.
laccolith
c.
stock
d.
sill
7.
What is the name of a large volcanic crater over 1 km in diameter?
a.
a caldera
b.
a stock
c.
a batholith
d.
a vent
8.
What is a pyroclastic flow?
a.
when lava comes out of a volcanic vent
b.
poisonous gas of a volcano
c.
a mixture of volcanic gas, ash, and other tephra
d.
lava that hardens into a batholith
9.
What is the name for an igneous intrusion that is smaller than a batholith but similar in shape?
a.
stock
b.
dike
c.
laccolith
d.
sill
10.
Rock fragments thrown into the air during a volcanic eruption are called __________.
a.
granite
b.
extrusive
c.
tephra
d.
lava
11.
What type of volcano forms from alternating layers of tephra and nonexplosive lava?
a.
shield volcano
b.
composite volcano
c.
cinder cone
d.
caldera
12.
When does magma form?
a.
when new minerals form due to chemical changes in the rock
b.
when volcanoes erupt
c.
when grains have been compacted together
d.
when temperatures are hot enough to melt rock
13.
What type of magma has the lowest silica content and is the least explosive?
a.
rhyolitic magma
b.
granitic magma
c.
andesitic magma
d.
basaltic magma
14.
Why does magma move up to and through Earth's crust?
a.
It is less dense than surrounding rock.
b.
It is more dense than surrounding rock.
c.
It is more viscous than ocean water.
d.
It is cooler than the crust.
15.
What are large, angular fragments thrown from a volcano called?
a.
lapilli
b.
ash
c.
volcanic bombs
d.
volcanic blocks
