1. Select the choice below that best describes the role of volatiles in an ascending magma.

-Volatiles increase the rate of crystallization in intrusive structures

-Volatiles will force the magma to contract as it rises

-Volatiles will shatter surrounding rocks, making it easier for the magma to rise

-Volatiles will expand with decreasing pressure, carrying the melt upward

2. The partial melting of a mafic magma would produce what composition of igneous rocks?

-Ultramafic

-Mafic

-Intermediate

-Felsic

3. What creates the small holes found in a vesicular texture?

-Liquid water

-Volatiles

-Soluble minerals

-Weathering

4. What is the geological definition of texture?

-How the sample feels to the touch

-The mineral content of the sample

-The percentage of silica in a sample

-Size and shape of mineral grains in the sample

5. What is the name of the pre-existing rock that is displaced by intrusive igneous bodies?

-Acid Rock

-Parent Rock

-Stock

-Country Rock

6. What is the term used to describe increased temperature with depth in the Earth?

-Decompression melting

-Convection cells

-Geothermal gradient

-Hydrothermal alteration

7. What magma would have formed from the partial melting of mantle material?

-Felsic Magma

-Primary Magma