1. Comparing the Layers of Earth
S6E5.a.

2. Which is the outermost layer?
THE CRUST
Thickness - 5km – 70km thick depending on location

3. The Crust: What’s it made of?
2 types of crust:
Oceanic – mostly basalt rocks
The thinnest crust
More dense than continental crust
Continental – mostly granite rocks
The thicker crust –less dense than Oceanic Crust

4. Next is the Mantle… Temp ranges from 1600 F to 6700 F
Beneath the crust
Thickness is 2900 km

5. The Mantle Made of 3 distinct areas: Lithosphere Asthenosphere
Lower Mantle

6. Lithosphere Thickness: approx 100 km thick Located directly
beneath the crust
Composition:
State of Matter
Solid
“Lithos” means “Stone”
Includes the Crust
Broken into large plates

7. Asthenosphere Thickness - 300 km Composition: Molten Material
State of Matter - Semi-Solid
“Asthenes” means “weak”
Includes convections currents that move plates above
Located right below the Lithosphere

8. Lower Mantle Thickness - 2500 km State of Matter Composition Solid
Very hot dense rock
Mg, Si, O, Fe

9. Outer Core Temperature = 6700 °F to 7800 °F Thickness - 2266 km
Located just beneath the
mantle
Composition:
Molten Metal (Fe & Ni)
State of Matter
Liquid

10. What makes the Outer Core unique?
Creates Earth’s magnetic field
- due to outer core rotating around inner core

11. Inner Core Temperature = 7800 °F to 13000 °F HOTTEST LAYER!!!
Thickness km
Composition:
Dense, solid metal ball of Fe & Ni!

12. What’s unique about the Inner Core?
Extreme pressure squeezes the atoms of the Fe & Ni so much, they cannot spread out!
Stays solid!

13. Seismic Waves
Seismic waves – generated by earthquakes – provide this evidence. The P and S waves are recorded by stations around the world P and S waves travel more quickly through more dense material and slow down when passing through less dense material

14. Seismic Waves Partially molten areas slow P waves and weaken S waves
S waves are completely stopped when passing through a liquid