Transcript Chapter 5 Earths Interior

Plate Tectonics
Breakdown of the Earth
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Composition
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Crust
Mantle
Core
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Structure
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Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
Crust
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Crust
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Continental Crust
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Outer most layer
5 – 100 km thick
Less than 1% of Earth’s mass
Minerals similar to granite, Less dense
Average thickness 30 km
Oceanic Crust
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Similar to basalt, dense
5 – 8 km thick
Lithosphere
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Lithosphere: “rock sphere”
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Outermost rigid layer
15 – 300 km thick
Made of crust and upper part of mantle
Divided into pieces known as “tectonic plates”
Tectonic Plates
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Pieces of the lithosphere that move
on top of the asthenosphere
Mantle
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Mantle
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Found between crust and core
2,900 km thick, 67% of Earth’s mass
Contains iron and magnesium, similar to the
mineral Olivine
Convection currents in the
Mantle
Mantle
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Asthenosphere: “weak sphere”
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Soft putty layer on which the lithosphere
moves upon
250 km thick
Mesosphere: “middle sphere”
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Lower Mantle
Strong interior structure
2,550 km thick
Core
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Core
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Outer core
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Comprised of iron, nickel, sulfur and oxygen
3,428 km thick
Liquid layer
2,200 km thick
Inner core
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Solid layer
1,228 km thick
Core Comparrison
Liquid Rock of the Core
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Pressure allows rock to be solid
Outer core has less pressure and is able
to spread out and become liquid.
Class example
How do scientists know
about the structure of the
Earth’s interior?
Measure different speed at which
seismic waves travel.
 Drilled to the center of the earth
 Volcanoes allow us to see into the
Earth
 Viewed satellite images from space
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Indirect Observation
Direct Observation