1. Earth Structure Notes

2. Composition (What it is made of) • Crust • Mantle • Core

3. Outer layer 5 - 100 km thick (3 – 60 miles thick) Made of oxygen & silicon 2 types of crust Oceanic (very dense, made of basalt) Continental (less dense, made of granite) The Crust

4. Oceanic and Continental Crust • Oceanic crust 3 – 5 miles thick • Continental crust on average 18 miles thick

5. Middle layer Very thick layer Made of iron & magnesium 2,900 km thick Solid near core Upper part is semi-solid The Mantle

6. The Core • Made mostly of iron & some nickel • 1/3 of the earth’s mass • Very hot • 3,428 km thick

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

8. Physical Structure of the Earth(5 Layers) • Lithosphere • Asthenosphere • Mesosphere • Outer Core • Inner Core (LAMOI)

9. The Lithosphere • Rigid outer layer (crust + top part of mantle) • Made of oxygen & silicon • Made of moving tectonic plates • 60 – 300 km thick

10. Tectonic Plates • Earth’s lithosphere is broken into about 19 pieces • These plates move on top of the asthenosphere

11. The Asthenosphere • Semi-solid; solid but flows like liquid, called PLASTICITY • Part of Mantle • Plates float on this layer; moved by convection currents • 250 km thick

12. The Mesosphere • Middle layer of Earth • Very strong solid layer • Lower part of mantle • 2,550 km thick

13. The Outer Core • Liquid layer • 4,000 – 5,000 Celsius • Made up of nickel & iron • 2,200 km thick

14. The Inner Core • Solid, very dense • 6,000 Celsius • Made up of iron • 1,228 km thick • Extreme pressure makes it solid even though it is still very hot