What is a rock? What is a rock? Where do we find rocks? Where do we find rocks? How are rocks classified?How are rocks classified? What is the Rock Cycle?What is the Rock Cycle?

What is a Rock?What is a Rock?

Naturally-occurring mixtures of Naturally-occurring mixtures of minerals, glass or organic matter.minerals, glass or organic matter.

Where do we find rocks?Where do we find rocks?

Rocks can be . . .Rocks can be . . . HardHard SoftSoft ShinyShiny DullDull SmoothSmooth RoughRough One colorOne color Many colorsMany colors

Classifying RocksClassifying Rocks Rocks are divided into 3 groups based on Rocks are divided into 3 groups based on

how they were formed:how they were formed:

Rocks

Igneous Sedimentary Metamorphic

Igneous RocksIgneous Rocks

Igneous RockIgneous Rock is formed when magma or lava is formed when magma or lava cools. cools.

Igneous rock can form:Igneous rock can form:– underground, where the magma (a hot underground, where the magma (a hot

liquid) cools slowly ORliquid) cools slowly OR– above ground, where the magma cools above ground, where the magma cools

quickly.quickly.

Igneous Rocks formed Igneous Rocks formed undergroundunderground (from lava or magma) (from lava or magma) usually have usually have LARGELARGE crystal grains crystal grains (they cooled (they cooled slowlyslowly))

Igneous Rocks formed above Igneous Rocks formed above groundground (from lava) usually have (from lava) usually have SMALL or NOSMALL or NO crystals (they cooled crystals (they cooled too too quicklyquickly))

Sedimentary RocksSedimentary Rocks Sedimentary RockSedimentary Rock is formed from sediments is formed from sediments

(rock fragments, mineral grains, animal & plant (rock fragments, mineral grains, animal & plant remains) that are pressed or cemented together.remains) that are pressed or cemented together.

Sedimentary rocks form at or near the earth's Sedimentary rocks form at or near the earth's surface at relatively low temperatures and surface at relatively low temperatures and pressurespressures

These sediments are moved by wind, water, ice or These sediments are moved by wind, water, ice or gravity.gravity.

Sedimentary rocks are Sedimentary rocks are fossilfossil-carrying rocks. They -carrying rocks. They can be formed underwater, too, and can be made can be formed underwater, too, and can be made up of bits of shells and skeletons of sea animals.up of bits of shells and skeletons of sea animals.

Metamorphic RockMetamorphic Rock Metamorphic RocksMetamorphic Rocks are those that are those that

have changed due to intense have changed due to intense temperature and pressure. temperature and pressure.

Metamorphic rocks CHANGE FORM. Both Metamorphic rocks CHANGE FORM. Both igneous rocks and sedimentary rocks can igneous rocks and sedimentary rocks can change into metamorphic rockschange into metamorphic rocks

Heat and pressure do not change the Heat and pressure do not change the chemical makeup of the parent rocks but chemical makeup of the parent rocks but they do change the physical properties they do change the physical properties of those rocks.of those rocks. This rock has many This rock has many layers.layers.

The Life of a RockThe Life of a Rock

Sedimentary Rock

Metamorphic

Igneous

Changes are made from pressure and

heat.

Layers of sediment join together.

Melted rock cools and hardens

Once a rock is formed, Once a rock is formed, does it stay the same does it stay the same

rock forever?rock forever? NONO!!

Rocks are Rocks are continually changedcontinually changed by many processes, such as by many processes, such as weathering, erosion, compaction, weathering, erosion, compaction, cementation, melting, and cementation, melting, and coolingcoolingRocks can change to and from Rocks can change to and from the three typesthe three types

Rocks become Rocks become biggerbigger, and , and biggerbigger, and , and

biggerbigger, and , and biggerbigger . . . . . .

By earthquakesBy earthquakes By volcanoesBy volcanoes By heat and By heat and

pressurepressure

Rocks become Rocks become smallersmaller, and , and smallersmaller, , and and smallersmaller,, and and smallersmaller. . .. . .

By erosionBy erosion By windBy wind By earthquakeBy earthquake By floodsBy floods By rainBy rain By mudslidesBy mudslides

The Rock Cycle SongThe Rock Cycle Song (Sing to the tune of "Row, Row, (Sing to the tune of "Row, Row,

Row Your Boat")Row Your Boat") SEDIMENTARY rockSEDIMENTARY rock

Has been formed in layersHas been formed in layers Often found near water sourcesOften found near water sources With fossils from decayersWith fossils from decayers

Then there's IGNEOUS rockThen there's IGNEOUS rock Here since Earth was bornHere since Earth was born Molten Lava, cooled and hardenedMolten Lava, cooled and hardened That's how it is formedThat's how it is formed

These two types of rocksThese two types of rocks Can also be transformedCan also be transformed With pressure, heat and chemicalsWith pressure, heat and chemicals METAMORPHIC rocks they’ll be.METAMORPHIC rocks they’ll be.

This rock is This rock is formed by formed by

cooling magma.cooling magma.IGNEOUSIGNEOUS

This type of rock can be This type of rock can be formed underwater. It is formed underwater. It is made up of bits of shells made up of bits of shells

and skeletons of sea and skeletons of sea animals.animals.

SEDIMENTARYSEDIMENTARY

This rock is formed by This rock is formed by intense heat & intense heat &

pressure.pressure.

METAMORPHIMETAMORPHICC

This rock is formed when This rock is formed when tiny grains of sand become tiny grains of sand become

cemented together.cemented together.

SEDIMENTARYSEDIMENTARY

This rock is formed This rock is formed by quickly cooled by quickly cooled

lava.lava.

IGNEOUSIGNEOUS

IGNEOUS ROCKS IGNEOUS ROCKS ARE FORMED BY:ARE FORMED BY:

Cooling Cooling Magma Magma or Lavaor Lava

Sedimentary rocks are Sedimentary rocks are formed when tiny grains of formed when tiny grains of

_______ become _______ become cemented together.cemented together.

SANSANDD

Let’s ReviewLet’s Review

A rock that has many layers, is flat, A rock that has many layers, is flat, and comes apart easily is most likely and comes apart easily is most likely which type?which type?– A. graniteA. granite– B. igneousB. igneous– C. metamorphicC. metamorphic– D. sedimentaryD. sedimentary