Question

Select the choice below that best describes the role of volatiles in an ascending magma.
A) Volatiles increase the rate of crystallization in intrusive structures.
B) Volatiles will force the magma to contract as it rises.
C) Volatiles will shatter surrounding rocks, making it easier for the magma to rise.
D) Volatiles will expand with decreasing pressure, carrying the melt upward.

Answer 1

Answer: Volatiles will expand with decreasing pressure, carrying the melt upward

Explanation:

Volatile refers to the gases which are dissolved in a magma. Examples of volatile include CO2, H2O and SO2.

The role of volatiles in an ascending magma is that the volatiles will expand with decreasing pressure, carrying the melt upward. Therefore, the correct option is D