Types of RocksSedimentary, 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

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?

Igneous Rocks

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 rock

Examples of Metamorphic Rocks