3 Groups of Rocks

There are only 3 groups of rocks, each is determined by how the rock formed All rocks are made from minerals

Igneous formed when melted rocks cool and harden http://topex.ucsd.edu/es10/lectures/lecture10/lecture10.html

2 Types EXTRUSIVE: Lava cooling on surface INTRUSIVE: Magma cooling in crust (Usually slow)

Some common ones are: Obsidian Granite Pumice Diorite

Metamorphic Rocks that are changed by extreme heat and pressure. Often found near mountains and deep in Earth http://geophysics.ou.edu/geol1114/notes/met_rx/met_rx.html

2 types: Nonfoliated Foliated Random mineral arrangement minerals arranged in layers or bands

Common Examples: Marble Schist Gneiss Slate quartzite

Sedimentary Rock When broken up pieces of rocks become compacted and cemented together. http://comp.uark.edu/~sboss/vrockbag.htm#sedimentary http://www.glogster.com/media/4/24/53/53/24535304.jpg

Usually found in places that were below water Made by weathering, erosion, deposition, compaction, and then cementation Usually found in places that were below water

Common Examples Sandstone Limestone Conglomerate shale

The Rock Cycle

It is the continual process that changes any type of rock into a different kind of rock. The cycle is very slow and never ending

Follow the arrows and 1 rock can turn into any of the other rock types. Erosion, deposition, compaction, and cementation Igneous Rock Sedimentary Rock Heat and pressure Cooling Melting Heat and pressure Erosion, deposition, compaction, & cementation Melting Melting Magma Metamorphic Rock