Your NameEarth Science P.#Date Notes: Igneous Rocks

Hot molten rock – inside the Earth = magma - outside the Earth = lava

Igneous Rx (rocks) are formed by the cooling of magma or lava

*Intrusive coarse-grained large crystals cools slowly Granite is most common-The Idaho Batholith is made of Granite

Gabbro

*Extrusive fine-grained small crystals cools quickly

Basalt is most common- Snake River Plain is made of basalt (picture near Twin

Falls)

Rhyolite

Silica makes thicker (viscous) magma that usually cools below surface. Silica rich magma that does make it to the surface is very explosive.

see your book page 119 - Do not copy down chart