Types of Rocks

Sedimentary, Igneous, Metamorphic

Sedimentary Rocks

• Made up of smaller rocks cemented together

• Sometimes have fossils• Usually have layers.

Sedimentary Rocks

• Form when loose sediment (rocks, sand) is deposited by water, compacted, and cemented together.

• Form as a chemical reaction in the water that leaves a chemical deposit, usually on an ocean bottom.

• Form along beaches, by rivers, or under the water in lake or oceans.

Sedimentary Rocks

Examples of Sedimentary Rocks

Igneous Rocks

• Some were once liquid magma that erupted from volcanoes. They cooled very quickly. (Extrusive)

• Others were once liquid magma, but they did not erupt from volcanoes. Instead, they cooled slowly underground. (Intrusive)

Igneous Rocks

• Extrusive:– Rocks that are from cooled lava (above

ground.– They cooled very quickly, therefore formed

small crystals

• Intrusive– Rocks that are from cooled magma (below

ground)– They cooled very slowly, therefore formed

large crystals.

Igneous Rocks

• Which is extrusive and which is intrusive?

Extrusive

Intrusive

Igneous Rocks

Examples of Igneous Rock

Metamorphic

• Form when igneous, sedimentary, or other metamorphic rocks are heated and/or squished, forming a new rock type.

• Usually has interlocking crystals and layers (called foliation)

Metamorphic

• This can either happen underground or above ground.– Underground: high pressure and heat– Above ground: volcano erupting

• When classifying metamorphic rocks, they always come from a parent rock.

Metamorphic Rocks

Examples of Metamorphic Rocks

Review

• What are the three rock types?• What are sedimentary rocks?• What are igneous rocks?• What are the two types of igneous

rocks?• What are metamorphic rocks?

Copyright Information

• All information was retrieved from research done on the internet in February 2007.

• All pictures were retrieved from a Yahoo image search in February 2007.