1. The Early Earth!

2. The Earth formed by accretion… The early history of Earth!

3. Eventually, a planet-sized body formed.

4. The planet heated up through contraction and radioactivity. And then DIFFERENTIATION occurred.

5. After the Earth formed by accumulation (about 4.6 Billion years ago…) …The Earth melted and differentiated into Core, Mantle, and Crust

6. Iron and other heavy elements sank toward the Earth’s center. IRON Light elements rose to the Earths Surface… Silicon Oxygen Differentiation! Core Crust

7. IRON CORE Silica-rich CRUST And an Iron-rich, Silica-poor MANTLE…

8. Just 8 Elements make up 98% of the Earth’s Crust! …and Silicon and Oxygen make up 70% of the Earth’s Crust by weight.

9. Silicon and oxygen combine with other elements to form SILICATES… Therefore… Silicates are the most common minerals in the Crust!

10. The Crust… …and very top of the Mantle are RIGID and BRITTLE. Lithosphere

11. The rest of the Mantle is “Plastic” (like “Putty” or clay… NOT liquid, but will slowly flow! Lithosphere Asthenosphere

12. Therefore… the brittle Lithosphere (Crust & upper Mantle) float and MOVE on the plastic Mantle (Asthenosphere). Lithosphere Asthenosphere This is the basis for PLATE TECTONICS!

13. Therefore… the brittle Lithosphere (Crust & upper Mantle) float and MOVE on the plastic Mantle (Asthenosphere). Lithosphere Asthenosphere This is the basis for PLATE TECTONICS!

14. Basic Plate Tectonics: The rigid, brittle Lithosphere moves on the plastic Mantle (Asthenosphere); the Continents go along for the ride! Crust Mantle