the earth ’s interior - quiathe model of earth ’s interior model developed using seismic waves...

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Copyright © 2008 Thomson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED.

The EarthThe Earth’’s Interiors Interior

Chapter 8Chapter 8

Objectives: 1) Draw a picture illustrating the different parts of the earth’s interior. 2) Write a simple description of the earth’s crust (lithosphere), mantle, inner core, and outer core.



EarthEarth’’s Cores Core

�� Three major parts or layers of the Three major parts or layers of the earthearth’’cc core:core:•• EarthEarth’’s core:s core:

�� Outer liquid portionOuter liquid portion

�� Inner solid portionInner solid portion

�� Composition believed to be iron and nickelComposition believed to be iron and nickel


Inner core: solid

Outer core: liquid

Mantle: The mantle is almost 2900 kilometers thick and comprises about 83% of the Earth's volume , it is solid


EarthEarth’’s Core s Core ((continuedcontinued))

�� 1,800 miles to outer core1,800 miles to outer core

�� 1,300 miles to inner core1,300 miles to inner core

�� Core is extremely hotCore is extremely hot–– 8,0008,000°°FF

�� Impossible to observe directly because Impossible to observe directly because it is so hot and has extremely high it is so hot and has extremely high pressurepressure


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The MantleThe Mantle

�� Makes up most of EarthMakes up most of Earth’’s volumes volume

�� Composed of a hot solid materialComposed of a hot solid material•• Silicon, oxygen, iron, aluminum, and Silicon, oxygen, iron, aluminum, and

magnesiummagnesium

•• 1,800 miles thick and extremely high 1,800 miles thick and extremely high pressurespressures

•• Heat moves upward through mantleHeat moves upward through mantle



The Mantle (The Mantle (continuedcontinued))

�� Extreme heat comes from:Extreme heat comes from:

1) Radioactive decay1) Radioactive decay

2) Friction2) Friction

3) Residual heat3) Residual heat

�� Upper mantle called the Upper mantle called the asthenosphereasthenosphere

•• Flows like thick syrupFlows like thick syrup

•• The rocks in this upper portion of the The rocks in this upper portion of the mantle are more rigid and brittle because mantle are more rigid and brittle because of cooler temperatures and lower of cooler temperatures and lower pressures. pressures.


EarthEarth’’s Crusts Crust

�� LithosphereLithosphere——solid outer crust of Earthsolid outer crust of Earth•• Made up of rock and hot plasticMade up of rock and hot plastic--like upper like upper

mantlemantle

�� Thickness from 40 miles to 3 milesThickness from 40 miles to 3 miles•• 40 miles under mountains40 miles under mountains

�� Continental crustContinental crust——density 2.7 gm/ccdensity 2.7 gm/cc

•• 3 miles under parts of the ocean3 miles under parts of the ocean�� Oceanic crustOceanic crust——density 3 gm/ccdensity 3 gm/cc

�� Denser because of pressure of oceanDenser because of pressure of ocean



EarthEarth’’s Crust s Crust ((continuedcontinued))

�� Oceanic crust made of basaltOceanic crust made of basalt

�� Earth floats on top of upper mantleEarth floats on top of upper mantle•• Like a cracker floating on soupLike a cracker floating on soup

�� Seven elements make up 99 percent of crustSeven elements make up 99 percent of crust•• Oxygen and silicon form 72 percent of the crustOxygen and silicon form 72 percent of the crust

•• Aluminum, iron, calcium, magnesium, sodium form Aluminum, iron, calcium, magnesium, sodium form remainderremainder

�� Lower crust and upper mantle form the Lower crust and upper mantle form the asthenosphereasthenosphere (plastic like)(plastic like)

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The Model of EarthThe Model of Earth’’s Interiors Interior

�� Model developed using seismic wavesModel developed using seismic waves

�� Also studied inner composition of meteoritesAlso studied inner composition of meteorites

•• Helps in understanding EarthHelps in understanding Earth’’s interiors interior

�� Deepest penetration by drilling is 9 milesDeepest penetration by drilling is 9 miles

�� Deepest mine is slightly over 2 milesDeepest mine is slightly over 2 miles

the earth ’s interior - quiathe model of earth ’s interior model developed using seismic waves...

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