Multiple Choice
Igneous intrusions often are associated with valuable
A. oil reservoirs B. ore deposits
C. fossil deposits D. radioactive elements
B. ore deposits
The process whereby some minerals melt at low temperatures while other minerals remain solid is called BLANK
partial melting
The process wherein different minerals form at different temperatures is called BLANK.
fractional crystallization
Magma that has a low silica content is called BLANK
basaltic
Why can minerals that form early in fractional crystallization form distinct crystal shapes.
They have space, in which to grow freely.
Which of the following is one of the most durable igneous rocks?
A. granite B. limestone
C. sandstone D. marble
A. granite
Because different minerals have different BLANK not all parts of a rock melt at the same time.
melting points
True
BLANK magma has the highest silica content.
Rhyolitic
How does pressure change with depth and why?
Pressure increases with depth from the weight of overlying root.
What are pegmatites?
A. veins of extremely large-grained minerals
B. microscopic, interlocking crystal grains
C. magmas of differing densities
D. small volcanoes
A. veins of extremely large-grained minerals
As each group of minerals crystallizes it removes elements from the remaining BLANK instead of adding new elements.
magma
Heat in the upper mantle and lower crust may come, in part, from the decay of radioactive elements.
TRUE or FALSE
True
Molten rock inside Earth's crust is called BLANK
magma
How does temperature change with depth in Earth's crust?
Temperature increases with depth in Earth's crust.
Diamonds can form only
A. near radioactive elements
B. above ground
C. under very low pressure
D. under very high pressure
D. under very high pressure
When magma cools, it crystallizes in the BLANK order of partial melting.
reverse
Contains moderate amounts of biotite, amphibole, and pyroxene
A. granitic
B. basaltic
C. intermediate
D. ultramafic
C. Intermediate
Magma that flows out on to Earth's surface is called BLANK.
lava
Do all minerals have the same melting point?
No, different minerals have different melting points.
Metal-rich quartz veins are formed at the end of
A. magma crystallization B. volcanic eruptions
C. radioactive decay D. the cooling of Earth's crust
A. magma crystallization
As each group of minerals melts, different BLANK are added to the magma mixture, changing its composition.
elements
Granite is an example.
A. granitic
B. basaltic
C. intermediate
D. ultramafic
A. granitic
A(n) BLANK is formed from the crystallization of magma.
igneous rock
How does pressure affect the melting point of rock?
As pressure increases, melting point increases.