Author Question: What was the rate of cooling and the environment of formation for an extrusive igneous rock and why? ... (Read 13 times)

dalyningkenk · **on:** Jul 16, 2018

What was the rate of cooling and the environment of formation for an extrusive igneous rock and why?

A) Slow because the magma was insulated below the surface
B) Fast because it was erupted from a volcano
C) Slow because it cooled in a volcanic lava flow far from the vent
D) Fast because it cooled 6 kilometers below the surface

Question 2

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, then melt upward.