Earth’s Layers

We Have 2 ways of Dividing Earth’s Layers:

Earth is divided into 3 compositional layers: 1. Crust 2. Mantle 3. Core

CRUST: Location: outermost layer Temperature: 0°C to 1,000°C Thickness: 5km to 100 km Composition: Oxygen, Silicon, and Aluminum

2 TYPES OF CRUST: Oceanic crust is very thin & dense. Continental crust is thick but less dense.

MANTLE: Location: below the crust. Temperature: 1,000°C to 3,700°C Thickness: 2,900 km Composition: Solid and molten rock, most of Earth’s mass

CORE: Location: Earth’s center Temperature: 3,700°C - 7,000°C Thickness: 3,500 km (combined) Composition: mostly iron, some nickel Divided into 2 layers: Outer Core Inner Core

Earth is divided into 5 physical layers: 1. Lithosphere 2. Asthenosphere 3. Mesosphere 4. Outer Core 5. Inner Core

LITHOSPHERE: This is the “crunchy” layer of the Earth. Location: crust and upper mantle Thickness: 15-300 km Lithosphere = tectonic plates

ASTHENOSPHERE: Location: the middle mantle Soft – can bend like plastic Lithosphere floats on this layer (like jello) Thickness: 250 km

MESOSPHERE: Location: the lower mantle Thickness: 2,550 km

Outer Core: Thickness: 2,300 km Composition: LIQUID iron (with some nickel) Thickness: 2,300 km

Inner Core: Composition: SOLID iron and a little nickel Solid because of increased pressure Thickness: 1,220 km thick

Lithosphere Asthenosphere Mesosphere CRUST MANTLE OUTER CORE INNER CORE

Density, Pressure, and Temperature Moving towards the center of the earth: Density increases Pressure increases Temperature increases

In Review: What are the 3 main layers of the Earth? Crust, Mantle, Core Which layer is the least dense? Crust Which core layer is solid iron and nickel? Inner core What is the name given to the “crunchy” layer of the crust and uppermost part of the mantle? Lithosphere 5. The motion in this layer is the reason Earth has a magnetic field. Outer core