Great Oxidation Event Transforms Earth's Atmosphere
c. 2.3 BYA · Prehistoric
Atmospheric oxygen levels rise as cyanobacterial photosynthesis overwhelms geological oxygen sinks. Dissolved iron in the oceans oxidizes from ferrous to ferric form, precipitating as banded iron formations. Free oxygen accumulates in the atmosphere, reaching perhaps 1-2% of modern levels. The resulting oxygenation triggers the Huronian glaciation by destroying atmospheric methane, a greenhouse gas, and causes mass die-off among anaerobic organisms unaccustomed to oxygen's reactive chemistry.
Locations
Global Oceans
Topics
cyanobacteriaphotosynthesisoxygenationbanded iron formationsatmospheric chemistryProterozoic
Connected Events — 3 Connections
Oxygen destroyed atmospheric methane, triggering the Huronian glaciation Huronian Glaciation: Earth's First Global Ice Age
The oxygenated environment following the Great Oxidation Event enabled the emergence of Francevillian macroscopic organisms Francevillian Biota: Early Evidence of Macroscopic Organisms
Oxygenic photosynthesis by cyanobacteria produced the oxygen that accumulated during the Great Oxidation Event Emergence of Oxygenic Photosynthesis
The Time Detectives® · Cadet Mission
Investigate This Event
Place it on the timeline. Earn points. Master the connections.
New to The Time Detectives?
Learn what it is →