Geologic Timeline

• [[Hadean]]: 4.571 BYA to 4.0 BYA
  • Named due to hellish conditions
• [[Archaean]]: 4.0 BYA to 2.5 BYA
  • Reasonably condusive to life
  • Pretty certain that cellular life originated here
  • 3.48 BYA: First cellular life, [[Stromatolites]]
  • 3 BYA: Oxygenic photosynthesis defines the end of the Archaean
• [[Proterozoic]]: 2.5 BYA to 541 MYA
  • 2.8 BYA to 1.9 BYA: Banded Iron Formations imply periods of high oxygenation
  • CH₄ (Methane) + 2O₂ → CO₂ + 2H₂O: Methane concentration decreased, while Oxygen and CO₂ increased
  • [[Huronian Glaciation]]
  • [[Ediacaran]]
• [[Phanerozoic]]: 541 MYA to Present
  • Started with a mass-extinction event
  • Divided into [[Paleozoic]], [[Mesozoic]], and [[Cenozoic]]