Exam 4: Magma, Igneous Rocks, and Intrusive Activity

What is the geologic definition of texture?

Mineral crystals that form early in the crystallization process will have better-developed crystal faces than later crystals.

________ is molten rock that is below the Earth's surface and retains most of its volcanic gases.

Which of the following best describes a pegmatitic texture?

Refer to the scenario above.How does this gradient compare to the average geothermal gradient?

Follow the geothermal gradient to the depth of 100 km.In which state of matter will peridotite exist at 100 km?

Most sills are intrusive igneous structures that display a fine-grained texture.

Which of the following statements best describes the relationship between pressure and melting point in the Earth's Interior?

________ is a felsic igneous rock with a meringuelike vesicular texture, consisting of very small holes, created by small shards of volcanic glass.

A ________ texture includes coarse phenocrysts surrounded by a phaneritic groundmass.

Plutonic bodies that have a surface exposure less than 100 km² are called ________.

Explain the processes occurring in the figure above that are generating magma.At what kind of tectonic boundary are such processes common?

What three components make up most magmas?

What creates the small holes found in a vesicular texture?

________ describes the formation of one or more secondary magmas from a single parent magma.

Which igneous texture has visible crystals that are a few millimeters across?

Will density increase or decrease with the crystallization of a magma?

Slow cooling produces ________ crystals, whereas fast cooling produces ________ crystals.

List the intrusive igneous textures below. Phaneritic, aphanitic, glassy, pyroclastic, pegmatitic

How does magma differ from lava?