1. Ancient Earth PAGE 31 OF INB

2. Essential Question:  How did the oceans and Atmosphere form?

3. THE PRESENT IS THE KEY TO THE PAST.

4. Review:  How did the Earth form?  What is the driving force behind the Nebular theory?  What do you think the Earth was like?

5. Hadean Eon: first 640 my  Extremely Hot: Asteroids and Radioactive decay.  Surface was covered with molten seas  Any land that formed was quickly destroyed.

6. Hadean Eon: first 640 my  Atmosphere: water vapor, Carbon Dioxide, poisonous gases.  NO OXYGEN!!!!  Similar to gases admitted by volcanos today.

7. Archean Eon: 4 – 2.5 mya  Interior 2x as hot as today  First long lasting surfaces, some still around. (oldest rocks)  Lots of small chunks of land called protocontinents  Convection currents moved the plates like today, but faster.

8. Archean Eon: 4 – 2.5 mya  First oceans form.  Salty due to acid rain  First critters: unicellular bacteria and Cyanobacteria (blue/green algae)  Formed mounds called Stromatolites.