8.4 Earth’s Layers. Layers by Composition Earth’s interior consists of three major zones defined...
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Transcript of 8.4 Earth’s Layers. Layers by Composition Earth’s interior consists of three major zones defined...
8.4 Earth’s Layers
Layers by Composition
Earth’s interior consists of three major zones Earth’s interior consists of three major zones defined by its chemical composition. defined by its chemical composition.
CrustCrust
MantleMantle
CoreCore
Crust
Thin, rocky outer layer of Earth, is divided into Thin, rocky outer layer of Earth, is divided into oceanic & continental crust. oceanic & continental crust.
Oceanic crust is made up of igneous rocks Oceanic crust is made up of igneous rocks basalt and gabbro.basalt and gabbro.
Continental crust is made up of many rock Continental crust is made up of many rock types.types.
Mantle
Over 82 % of Earth’s volume is contained in Over 82 % of Earth’s volume is contained in the mantlethe mantle
Mantle – a solid, rocky shell that extends to a Mantle – a solid, rocky shell that extends to a depth of 2890 km.depth of 2890 km.
The boundary between the crust & mantle The boundary between the crust & mantle shows a change in chemical composition.shows a change in chemical composition.
Core
Sphere composed of an iron-nickel alloy. Sphere composed of an iron-nickel alloy.
Extreme pressure is found here.Extreme pressure is found here.
Layers by Physical Properties
Earth’s interior gradually increases in temperature, Earth’s interior gradually increases in temperature, pressure, and density with depth.pressure, and density with depth.
Earth is divided into layers based on their physical Earth is divided into layers based on their physical propertiesproperties
LithosphereLithosphere
AsthenosphereAsthenosphere
Outer CoreOuter Core
Inner CoreInner Core
Lithosphere & Asthenosphere
Lithosphere – Earth’s outermost layer that Lithosphere – Earth’s outermost layer that consists of the crust and uppermost mantle. It consists of the crust and uppermost mantle. It forms a relatively cool, rigid shellforms a relatively cool, rigid shell
Asthenosphere – located below the Asthenosphere – located below the lithosphere. Relatively soft, and weaker layer. lithosphere. Relatively soft, and weaker layer. Warmer than the lithosphereWarmer than the lithosphere
Lower Mantle
Located near the base of the mantle Located near the base of the mantle
More rigid layerMore rigid layer
Rocks are still very hot and capable of gradual Rocks are still very hot and capable of gradual flowflow
Inner & Outer Core
Composed mainly of iron-nickel alloyComposed mainly of iron-nickel alloy
Divided into 2 main regions that both have Divided into 2 main regions that both have different physical propertiesdifferent physical properties
Outer Core- liquid layer; flow of metallic iron in this Outer Core- liquid layer; flow of metallic iron in this zone is what creates the Earth’s magnetic fieldzone is what creates the Earth’s magnetic field
Inner Core- High temperatures; material is Inner Core- High temperatures; material is compressed into a solid state by the high pressurecompressed into a solid state by the high pressure