plutons

What happens when magma cools underground?

It forms intrusive igneous rock bodies.

What does “intrusive” mean when describing igneous rock bodies?

It means inside Earth.

Where do new rock bodies form in relation to older rocks?

They intrude inside the cracks and fissures of older rocks.

What are two possible shapes of new rock bodies formed from cooling magma?

Some are thin and ribbonlike

What is the name for the intrusive igneous rock bodies formed by cooling magma?

Plutons.

How can plutons eventually be exposed at Earth’s surface?

Through uplift and erosion.

What determines the type of pluton (batholith

stock

What determines the type of rock (basalt

andesite

What type of magma creates basalt rocks?

Basaltic magma.

What type of magma creates andesite rocks?

Andesitic magma.

What type of magma creates granite rocks?

Rhyolitic magma.

What types of rocks can plutons be composed of?

Basalt

What is the largest type of magma chamber called?

Batholith.

What shape and texture do batholiths typically have?

Irregular shaped and coarse-grained.

How long does it take for batholiths to form?

Millions of years.

Where are batholiths commonly found?

Interiors of major mountain chains.

What type of rock are batholiths mostly made of?

Granite.

What type of pluton is similar to a batholith but smaller in size?

Stock.

What can stocks be thought of as in relation to batholiths?

Subchambers of batholiths.

What shape is a laccolith

and how does it form?

How does the size of a laccolith compare to batholiths and stocks?

Smaller.

What type of pluton forms when magma intrudes parallel to rock layers?

Sill.

What is the texture of sills?

Coarse-grained.

What type of pluton cuts across (perpendicular to) preexisting rock layers?

Dike.

What is the texture of dikes?

Coarse-grained.