RocksRocks

And the Rock And the Rock CycleCycle

The Rock CycleThe Rock Cycle

Rock CycleRock Cycle

RocksRocks A mixture of minerals, A mixture of minerals,

mineraloids, glass, or organic mineraloids, glass, or organic matter.matter.

Three main types of RockThree main types of Rock– IgneousIgneous– MetamorphicMetamorphic– SedimentarySedimentary

The Rock CycleThe Rock Cycle

The changing of rocks from one form to The changing of rocks from one form to another by processes such as another by processes such as weathering, erosion, compaction, weathering, erosion, compaction, cementation, melting, and coolingcementation, melting, and cooling..

IgneousIgneousRocksRocks

Igneous RockIgneous Rock

The beginning of the The beginning of the Rock CycleRock Cycle

Igneous RocksIgneous Rocks

Starts as MAGMA… Starts as MAGMA… rock that has melted rock that has melted from pressure and heat from pressure and heat in the Earthin the Earth

Pressure and heat Pressure and heat buildbuild

Magma rises to Magma rises to surfacesurface

Comes out in Volcano Comes out in Volcano as LAVAas LAVA

Intrusive Vs. ExtrusiveIntrusive Vs. Extrusive Rocks form below Rocks form below

Earth’s surfaceEarth’s surface Cool slowlyCool slowly Large crystals formLarge crystals form ExamplesExamples

– GraniteGranite

– DioriteDiorite

– GabbroGabbro

Rocks form when lava Rocks form when lava cools on or near cools on or near Earth’s surfaceEarth’s surface

Fast coolingFast cooling Small crystals formSmall crystals form ExamplesExamples

– ObsidianObsidian

– PumicePumice

– BasaltBasalt

IntrusiveIntrusive

GraniteGranite

Notice the crystalsNotice the crystals The crystals are pieces The crystals are pieces

of mineralof mineral

DioriteDiorite

GabbroGabbro

ExtrusiveExtrusive

ObsidianObsidian

RhyoliteRhyolite

PumicePumice

BasaltBasalt

ScoriaScoria

AndesiteAndesite

Three Compositions that effect Three Compositions that effect Igneous Rock TypesIgneous Rock Types

BasalticBasaltic GraniticGranitic AndesiticAndesitic

Dense, heavyDense, heavy

Dark ColoredDark Colored

Rich in Fe, MgRich in Fe, Mg

HawaiiHawaii

Light ColoredLight Colored

Lower DensityLower Density

Thick and StiffThick and Stiff

Lot of Si, OLot of Si, O

Violent EruptionViolent Eruption

Halfway Halfway between otherbetween other

twotwo

Igneous Rock TypesIgneous Rock Types

G a bb ro

In trus ive

B a sa ltS co ria

E x tru s ive

B a sa lt ic

D io rite

In trus ive

A n de s ite

E x tru s ive

A n d e s it ic

G ra n ite

In trus ive

R h yo liteP u m ice

O b sid ian

E x tru s ive

G ra n it ic

In g eo u s ro cks

BasalticBasaltic

AndesiticAndesitic

GraniticGranitic

MetamorphicMetamorphicRocksRocks

Metamorphic RocksMetamorphic Rocks

Rocks that have changed due to temperature Rocks that have changed due to temperature and pressure increases or that undergo and pressure increases or that undergo changes in compositionchanges in composition

Can be formed from:Can be formed from:– Igneous RocksIgneous Rocks– Sedimentary RocksSedimentary Rocks– Metamorphic RocksMetamorphic Rocks

Formation of Metamorphic Formation of Metamorphic RocksRocks

Rocks beneath the Rocks beneath the surface under pressure surface under pressure and heatand heat

Once reach critical pt, Once reach critical pt, rocks meltrocks melt

Or mineral grains are Or mineral grains are flattenedflattened

New rocks formed by New rocks formed by combination of combination of processesprocesses

Classification of MetamorphicClassification of Metamorphic

FoliatedFoliated When mineral grains When mineral grains

flatten and line up in flatten and line up in parallel bandsparallel bands– SlateSlate– GneissGneiss

NonfoliatedNonfoliated When no banding When no banding

occurs during occurs during formationformation– QuartiziteQuartizite– MarbleMarble

Before and AfterBefore and After

ShaleShale SlateSlate

Before and AfterBefore and After

GraniteGranite GneissGneiss

Before and AfterBefore and After

SandstoneSandstone QuartziteQuartzite

Before and AfterBefore and After

LimestoneLimestone MarbleMarble

The Rock Cycle NowThe Rock Cycle Now

SedimentarySedimentaryRocksRocks

Sedimentary RocksSedimentary Rocks

Sediments and Sedimentary Sediments and Sedimentary RocksRocks

Sedimentary rock are made when sediments Sedimentary rock are made when sediments become pressed or cemented together or become pressed or cemented together or when sediments precipitate out of a solutionwhen sediments precipitate out of a solution

Sediments are loose materials such as rock Sediments are loose materials such as rock fragments, mineral grains, bits of plants and fragments, mineral grains, bits of plants and animals that have been moved by wind, animals that have been moved by wind, water, ice, or gravitywater, ice, or gravity

How they are madeHow they are made

11stst wind and/or water wind and/or water erode existing rockerode existing rock

22ndnd wind, water, ice, wind, water, ice, or gravity move or gravity move sediments to a new sediments to a new locationlocation

33rdrd new rocks are made new rocks are made by compaction or by compaction or cementationcementation

The two C’s that make Sed. RockThe two C’s that make Sed. Rock

Compaction:Compaction: after after erosion has moved erosion has moved sediment to new sediment to new location, pressure location, pressure from upper layers from upper layers pushed down on lower pushed down on lower layers and small layers and small sediments stick sediments stick togethertogether

Cementation:Cementation: from from large sediments, water large sediments, water socks through soil and socks through soil and rock and dissolves rock and dissolves minerals (calcite, minerals (calcite, hematite, & limonite) hematite, & limonite) these fill small spaces these fill small spaces in-between and hardenin-between and harden