Rocks Rock!!!: Igneous, Metamorphic, and Sedimentary

I. Igneous Rocks A. Forms when magma cools and hardens

Igneous (cont.) A. 2 Types 1. Intrusive igneous rock: magma cools deep below crust Extrusive igneous rock: magma/lava cools on the surface

Intrusive Igneous Rocks

Extrusive Igneous Rocks

Igneous (cont.) Texture or crystal size depends mostly on cooling rate 1. intrusive  cools slowly a. Large crystals b. Ex. Granite 2. Extrusive  cools rapidly a. Small crystals b. Ex. Slate, Obsidian

Igneous (cont) Some magma contains lots of dissolved gas  becomes trapped in rock  forms holes when it cools Ex. Pumice

II. Metamorphic Rocks A. Rocks that form from the alteration of existing rocks

Metamorphic (cont.) These changes occur by a. Heat b. Pressure c. Chemical change

III. Sedimentary Rocks A. Sedimentary rocks are made by compaction and cementation, this process is called LITHIFICATION

Conglomerate: Large rock made up of smaller rocks

Sedimentary (cont) A. Texture: gives clues to the environment of where it was deposited

Sedimentary (cont) Grain Size: shows how far the sediment traveled a. Large grain: did not travel far b. Small grain: traveled farther

Sedimentary (cont) Grain Shape: shape of grains in rock a. Angular: did not travel far enough to round out edges b. Rounded: traveled far enough to round out the edges