Layers of the Earth

1. Layers of the Earth Unit 2: Tectonic Processes Ms. Thind Geog 12

2. How old is the earth? Approximately 4.5 BILLION years old! 70% Water, 30% Land

3. What is it made of? • Mantle • Continental and Oceanic Crust • Core • Lithosphere • Centrosphere • Mesosphere • Asthenosphere • Atmosphere • Hydrosphere

4. Centrosphere • “core” center of the earth • Consists of inner core and outer core • Composed of iron, nickel, and heavy metals • Core in solid state due to ↑ pressure

5. Mesosphere • Known as the mantle • Solid layer between earth’s core and then asthenosphere

6. Asthenosphere • Plastic layer of the upper mantle directly below lithosphere

7. Lithosphere • Outer layer that surrounds the earth • Brittle- can be cracked, warped and buckled • Ends at the “moho” (Mohorovicic discontinuity): defined line of contact • Within the lithosphere: - Crust: thin outer layer of rock - Continental Crust - Oceanic Crust

8. Hydrosphere • Covering of water on the earth • Has irregularities due to the lithosphere Atmosphere • True outer covering of the earth • Mixture of gases: nitrogen and oxygen

9. Earth’s Layers: • How are the earth’s layers similar to an egg? • Shell=crust • Egg white=mantle • Yolk=core