Transcript 8.4 Earth`s Layers

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