4 Main Layers

• Crust

• Mantle

• Outer Core

• Inner Core

Crust

Thinnest layer (5 – 70 km below surface)

◦Continental crust = thicker

◦Oceanic crust = thinner

Made up of solid rock

Mantle

Made of three Parts & makes up 2/3 of the Earth:

1. Lithosphere – Very top of mantle AND the crust, made up of solid rock, broken into plates

2. Asthenosphere – below lithosphere, “soft” solid rock, “plastic-like” (able to flow SLOWLY)

3. Mesosphere (Lower Mantle) – solid rock

Outer Core

Liquid metal (nickel and iron)

Responsible for Earth's magnetic field

2300 kilometers thick

Inner Core

Solid metal (nickel and iron) due to intense pressure

The inner core has the highest temperature and pressure of all the layers

Convection and the Mantle

Heat Source – Core

Heated rock from the bottom of the asthenosphere rises up towards the crust

Cooler rock near the crust is more dense, and is pulled back into the mantle towards the core

Convection in the Mantle

Convection currents in Earth’s mantle cause the mantle to slowly move, carrying the plates above it along with it in different directions.