Great Oxidation Event
Gran Oxidación de la atmósfera
- Date
- c. 2400 Ma · confidence medium
- Place
- Huronian Supergroup, Ontario, Canada
- Credited to
- Natural event
- Field
- Cosmos & Earth
What was discovered
Cyanobacteria fill the atmosphere with free oxygen for the first time, changing the chemistry of oceans and rocks and triggering the Huronian glaciation, whose deposits survive in Ontario.
Planetary event (F5), verified against sources on 25-09-2026.
What it led to
- Huronian glaciation
- Aerobic life