1. Plate Tectonics

2. Breakdown of the Earth Composition Structure Crust Mantle Core
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core

3. Crust Crust Continental Crust Oceanic Crust Outer most layer
5 – 100 km thick
Less than 1% of Earth’s mass
Continental Crust
Minerals similar to granite, Less dense
Average thickness 30 km
Oceanic Crust
Similar to basalt, dense
5 – 8 km thick

4. Lithosphere Lithosphere: “rock sphere” Outermost rigid layer
15 – 300 km thick
Made of crust and upper part of mantle
Divided into pieces known as “tectonic plates”

5. Tectonic Plates
Pieces of the lithosphere that move on top of the asthenosphere

6. Mantle Mantle Found between crust and core
2,900 km thick, 67% of Earth’s mass
Contains iron and magnesium, similar to the mineral Olivine

7. Convection currents in the Mantle

8. Mantle Asthenosphere: “weak sphere” Mesosphere: “middle sphere”
Soft putty layer on which the lithosphere moves upon
250 km thick
Mesosphere: “middle sphere”
Lower Mantle
Strong interior structure
2,550 km thick

9. Core Core Outer core Inner core
Comprised of iron, nickel, sulfur and oxygen
3,428 km thick
Outer core
Liquid layer
2,200 km thick
Inner core
Solid layer
1,228 km thick

10. Core Comparrison

11. Liquid Rock of the Core Pressure allows rock to be solid
Outer core has less pressure and is able to spread out and become liquid.
Class example

12. How do scientists know about the structure of the Earth’s interior?
Measure different speed at which seismic waves travel.
Drilled to the center of the earth
Volcanoes allow us to see into the Earth
Viewed satellite images from space

13. Indirect Observation

14. Direct Observation