1. Earth’s Layers

2. Earth is divided into 3 basic layers:
1. Crust
2. Mantle
3. Core
These layers are then subdivided into smaller layers.

3. CRUST:
Is the outermost layer on the earth.
Thickness varies. Under mountains it can be as thick as 60 km and less than 5 km under the ocean.
It is the least dense of all the layers. (lightest layer)
It is made up of silicon, oxygen, and aluminum.

4. 2 TYPES OF CRUST:
Oceanic crust is very dense and thinner then continental crust.
Continental crust is less dense and thicker than oceanic crust.

5. MANTLE:
Located below the crust.
It is the largest layer (about 2900 km thick). Rock layers are movable.
Hot soften rocks made up of more magnesium and iron.
Convection takes place in the mantle where cooler rock sinks and warmer rock rises

6. MANTLE: Divided into 2 parts
Upper mantle
Lower mantle.

7. CORE: (Egg Yolk)
Located below the Mantle.
It is divided into 2 layers
Outer Core
Inner Core

8. Outer Core:
is liquid and is made up of mostly iron.
The core is the densest layer and makes up about one-third of the Earth’s mass.

9. Inner Core:
Is the center of the Earth – 1200 km thick.
It’s solid iron and nickel. Most dense layer
The increased pressure causes the I.C. to be solid

10. In your notes lets draw together a diagram of the Earth.
CRUST
MANTLE
OUTER CORE
INNER CORE

12. The outermost, rigid layer of the Earth.
Look at the sub-layers of the mantle
LITHOSPHERE:
The outermost, rigid layer of the Earth.
It includes the crust and the very uppermost part of the upper Mantle .
Divided into pieces called tectonic plates
ASTHENOSPHERE:
Soft – layer in the upper portion of the mantle and is made up of rock that flows slowly.
It is located right below the Lithosphere.
Lithosphere floats on this layer.

13. Lithosphere
Asthenosphere
CRUST
MANTLE
OUTER CORE
INNER CORE

14. In Review:
Mesosphere- The strong , lower part of the mantle.
Rock in the mesosphere flows more slowly than rock in the asthenosphere.