Earth’s layers

The Dynamic Earth, the inside

1. Earth’s Layers
SC Standard 8-3.1 Summarize the 3
layers of Earth on the basis of relative
position , density and composition.

2. Earth is divided into Earth is divided into 3 basic 3 basic
layerslayers::
1. Crust1. Crust
2. Mantle2. Mantle
3. Core3. Core
These layers are then These layers are then
subdivided into smaller layers.subdivided into smaller layers.

3. CRUSTCRUST::
•Is the Is the outermost layeroutermost layer on the earth. on the earth.
(EGG SHELL)(EGG SHELL)
•Thickness variesThickness varies. Under mountains . Under mountains
it can be as thick as 60 km and less it can be as thick as 60 km and less
than 5 km under the ocean.than 5 km under the ocean.
•It is the It is the least denseleast dense of all the layers. of all the layers.
(lightest layer)(lightest layer)
•It is made up of It is made up of siliconsilicon and and oxygenoxygen..

4. • Oceanic crustOceanic crust is is
very dense, made very dense, made
of of Basalt.Basalt.

• Continental crustContinental crust
is less dense, is less dense,
made of made of Granite.Granite.
2 TYPES OF CRUST2 TYPES OF CRUST ::

5. BASALT
GRANITE

6. MANTLEMANTLE ::
• Located Located belowbelow the crust. the crust. (Egg (Egg
White)White)
• It is the It is the largest layerlargest layer (about 2900 (about 2900
km thick). Rock layers are km thick). Rock layers are
movable. (plastic)movable. (plastic)
• Hot soften rocks made up of more Hot soften rocks made up of more
magnesiummagnesium and and ironiron..
• Density increasesDensity increases with depth due with depth due
to increase in pressure.to increase in pressure.

7. MANTLEMANTLE : : Divided into 2 partsDivided into 2 parts
• Upper mantleUpper mantle
• Lower mantleLower mantle..
• Contains the “Moho” Contains the “Moho” (Mohorovicic (Mohorovicic
discontinunity)discontinunity)

8. CORECORE: : (Egg Yolk)(Egg Yolk)
• Located below the Mantle.Located below the Mantle.
• It is divided into 2 layersIt is divided into 2 layers
Outer CoreOuter Core
Inner CoreInner Core

9. Outer CoreOuter Core::
• is is liquidliquid and is made up of mostly and is made up of mostly
ironiron (easily magnetized)(easily magnetized)
• The movement of materials in the The movement of materials in the
liquid O.C. is liquid O.C. is inferredinferred to be the to be the
cause of Earth’s cause of Earth’s magnetic fieldmagnetic field!!
(highlight in your notes)(highlight in your notes)
• The O.C. is about 2250 km thick.The O.C. is about 2250 km thick.

10. Inner CoreInner Core::
• Is the Is the centercenter of the Earth – 1200 of the Earth – 1200
km thick.km thick.
• It’s It’s solidsolid iron and nickel. Most iron and nickel. Most
dense layer (heaviest) dense layer (heaviest) (highlight in (highlight in
notes)notes)
• The increased pressure The increased pressure
causes the I.C. to be solidcauses the I.C. to be solid

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

13. Look at the sub-layers of the mantle
LITHOSPHERELITHOSPHERE : :
• This is the “crunchy” layer of the Earth.This is the “crunchy” layer of the Earth.
• It includes the It includes the crustcrust and the very and the very
uppermost part of the upper Mantleuppermost part of the upper Mantle
ASTHENOSPHEREASTHENOSPHERE : :
• Soft – can bend like plastic, layer in the Soft – can bend like plastic, layer in the
upper portion of the mantleupper portion of the mantle
• It is located right below the Lithosphere.It is located right below the Lithosphere.
Lithosphere floats on this layer (like jello)Lithosphere floats on this layer (like jello)

14. CRUST
MANTLE
OUTER CORE
INNER CORE
Lithosphere
Asthenosphere

15. In Review:
1.What are the 3 main layers of the Earth?
Crust, Mantle, Core
2.Which layer is the least dense?
Crust
3.Which core layer is solid iron and nickel?
Inner core
4.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