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Types of RockBy Paige BlackEmily.black@smail.astate.edu

1WHAT are rocks?A rock is a naturally occurring solid mixture of one or more minerals, or organic matter.Rocks are classified by how they are formed, their composition, and texture.Rocks change over time through the rock cycle.

23 types of rocksIgneous RocksExamples: granite, basalt, pumice, flint Sedimentary RocksExamples: limestone, chalk, sandstoneMetamorphic RocksExamples: slate, marble, quartzite

3Igneous rocksThese are rocks that solidified directly from magma.

Magma can form:When rock is heatedWhen pressure is releasedWhen rock changes compositionMagma freezes between 700C and 1,250C.Magma is a mixture of many minerals.

4Igneous rocksTypes of Composition:Felsic- light colored rocks that are rich in elements such as aluminum, potassium, silicon, and sodiumMafic- dark colored rocks that are rich in calcium, iron, and magnesium, poor in siliconCoarse-grained- takes longer to cool, giving mineral crystals more time to growFine-grained- cools quickly with little to no crystals 5Igneous rocksTypes of Formation:Intrusive- magma pushes into surrounding rock below the Earths surface

Extrusive- magma erupts onto the Earths surface (lava), cools quickly with very small or no crystals formed

6Sedimentary rocksThe rocks are formed when igneous rocks are eroded as a sediment under the sea.Sediments are moved from one place to another.Sediments are deposited in layers, with the older ones on the bottom.The layers become compacted and cemented together.7Sedimentary rocksThree Types:Clastic- made of fragments of rock cemented together with calcite or quartzExample: SandstoneChemical- minerals crystallize out of solution to become rockExample: Halite (Rock Salt)Organic- any accumulation of sedimentary debris caused by organic processesExample: Coal

8Metamorphic rocksMeans change in formChanges with temperature and pressure, but remains solid

Usually takes place deep in the EarthMake up a lot of the Earths crust

9Metamorphic rocksTwo Types:Contact- when magma is injected into the surrounding rock solid. Increased temperature changes the composition of the rock, minerals are changed into new minerals.

Regional- changes in great masses of rock over a wide area. Large pieces of the Earths crust collide and the rock is deformed and chemically changed by heat and pressure.

10Metamorphic rocksTwo Types of Texture:Foliated- contain aligned grains of flat mineralsExample: Slate

Non-foliated- mineral grains are not arranged in bands or plainsExample: Marble

113 Types of RocksIgneous

Sedimentary

Metamorphic

12resourceshttp://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry13.html http://en.wikipedia.org/wiki/Igneous_rock http://en.wikipedia.org/wiki/Sedimentary_rock http://en.wikipedia.org/wiki/Metamorphic_rock Google Images for Pictures13