Earth’s LayersEarth’s Layers

CrustCrustOuter most layerOuter most layerThinnestThinnest5 to 100 kilometer (km) 5 to 100 kilometer (km) thickthick

Temperatures range Temperatures range from 0from 0° C to 1000°C° C to 1000°C

CrustCrust Composition: Composition:

mostly silicon, oxygen, mostly silicon, oxygen, sodium, small amounts of sodium, small amounts of magnesium, potassium, magnesium, potassium, and iron.and iron.

CrustCrust

Continental CrustContinental CrustThickest up to 100 km Thickest up to 100 km at mountainsat mountains

Most abundant rock is Most abundant rock is granitegranite

““Two Types”Two Types”

Oceanic CrustOceanic CrustAs thin as 5 kmAs thin as 5 kmMost abundant rock is Most abundant rock is basaltbasalt

Density averages 3g per Density averages 3g per cmcm³³

Crust/MantleCrust/Mantle

Mohorovicic Mohorovicic Discontinuity (Moho):Discontinuity (Moho):Transition boundary Transition boundary between the crust and between the crust and mantlemantle

Crust/MantleCrust/Mantle

Mohorovicic Mohorovicic Discontinuity (Moho):Discontinuity (Moho):This boundary marks a This boundary marks a significant change in significant change in chemical composition.chemical composition.

MantleMantle

67% of Earth’s mass67% of Earth’s mass2,900 km thick2,900 km thickTemperature ranges Temperature ranges from 1000from 1000° C to 3700 ° ° C to 3700 ° C C

MantleMantleDensity averages from Density averages from 4.3g to 5.4g per cm4.3g to 5.4g per cm³³

Composition: mostly Composition: mostly silicon, oxygen, silicon, oxygen, magnesium, and ironmagnesium, and iron

MantleMantleConvection currents Convection currents occur hereoccur here

MantleMantle

Divided into 3 layers: Divided into 3 layers: 1. Lithosphere1. Lithosphere2. Asthenosphere2. Asthenosphere3. Mesophere3. Mesophere

MantleMantle Lithosphere:Lithosphere:

10 to 300 km thick10 to 300 km thickSolid and made up of crust Solid and made up of crust and mantle materialand mantle material

VERY rigidVERY rigidDivided into sections Divided into sections called platescalled plates

MantleMantle

AsthenosphereAsthenosphere250 km thick250 km thickSoft layer that allows Soft layer that allows plates to shiftplates to shift

MantleMantle

MesosphereMesosphere2550 km thick2550 km thickLower part of the Lower part of the mantlemantle

CoreCore

Divided into 2 layers:Divided into 2 layers:1. Outer Core1. Outer Core2. Inner Core2. Inner Core

CoreCoreOuter CoreOuter Core

LiquidLiquid2200 km thick2200 km thick

CoreCore

Outer Core:Outer Core:Composition: Iron and Composition: Iron and Nickel, 10% sulfur and Nickel, 10% sulfur and oxygenoxygen

CoreCoreOuter Core:Outer Core:

Density: 10g to 12g Density: 10g to 12g per cmper cm³³

Temperature: 4000° to Temperature: 4000° to 5000° C5000° C

CoreCoreInner Core:Inner Core:

SolidSolid1230 km thick1230 km thickAbout 6380 km About 6380 km beneath Earth’s surfacebeneath Earth’s surface

CoreCore Inner Core:Inner Core:

Composition: Iron and Composition: Iron and NickelNickel

Density: 15 g per cmDensity: 15 g per cm³³Temperature: 5000° to Temperature: 5000° to 6000° C6000° C

Earth’s LayersEarth’s LayersScientists use indirect Scientists use indirect methods to gain methods to gain information and information and knowledge of Earth’s knowledge of Earth’s interior (example: interior (example: earthquakes).earthquakes).

Earth’s LayersEarth’s LayersSeismic waves from Seismic waves from earthquakes travel at earthquakes travel at different speeds depending different speeds depending on the density and on the density and composition of the ground composition of the ground they move through. they move through.

Earth’s LayersEarth’s Layers

Scientists are able to Scientists are able to take this information take this information and learn about the and learn about the interior of Earth.interior of Earth.