Volcanoes

Pockets of magma push their way to the surface. 

Magma is molten rock, and is less dense than solid rock so it pushes it's way through the cracks in the crust from the Pluton by:
1.  wedging up the rock
2.  pushing up the rock
3.  breaking the rocks

Plutons are very large pools of magma under the surface of the earth that can be many miles long.


Eruptions consist of 3 main things:

1.  gases:  water vapor, carbon dioxide, and sulfur dioxide are the most common
2.  pyroclasts:  fire pieces, ash (shredded magma), bombs (molten rock), and blocks (solid rock)
3.  lava: magma that is no longer below the surface of the earth (least common)


There are 2 main types of explosion:

1.  Explosive:  thicker, Felsic magma, produces lightly colored rocks, very sticky and viscous
2.  Non-Explosive:  thinner, Basaltic magma, produces very darkly colored rocks, very fluid


Benefits of volcanic eruptions:

1.  Fertile soil
2.  abundance of economic minerals
3.  atmosphere and oceans created by the release of gases