Igneous Process: Joe vs. the Volcano

Granite (Arcadia, Great Smokey Mt.)

Commonly used for tombstones and monuments and as building stones Well known areas in the US are Vermont, North Carolina and Minnesota coarse-grained rock composed of about 10-20% quartz and about 50% potassium feldspar.

Andesite (Mt Saint Helen's)

A type of Granite that is located near the surface Medium-gray, fine grained rock typically of volcanic origin

Rhyolite (Yellowstone, Crater Lake)

Fine-grained equivalent of granite and is composed of light colored silicates contains glass fragments and voids, indicating that it cooled rapidly in a surface large intrusive masses thick rhyolite lava flows and extensive ash deposits in and around Yellowstone NP

Extrusive Igneous rocks

They form on the and have smaller crystals Also called volcanic rocks

Intrusive Igneous rocks

They form underground and have larger crystals Also known as plutonic rocks

Basalt (Hawai'i)

composed primarily of pyroxene and calcium-rich plagioclase feldspar most common extrusive igneous rock the upper layers of the oceanic crust consists of basalt

Igneous Rock (ignis = fire)

forms as molten rock cools and solidifies composed mainly of silicate minerals

Magma

is formed by partial melting that occurs at various levels within Earth's crust and upper mantle to depths of about 250 kilometers

Granite Parks

Arcadia NP Yosemite NP

National Parks with a Crater Lake

Crater Lake NP

Lava

When molten rock reaches Earth's surface Lava is emitted as fountains that are produced when escaping gasses propel it from a magma chamber Can be explosively ejected, producing dramatic steam and ash eruptions