Copy - Archean Eon

Aydan Abalo

Archean Eon

4-2.5 billion years ago

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Major Event

Interesting Facts

A major event that occured during the Archean Eon was known as the Huronian Glaciation. This event lasted for nearly 300 million years and this happened when the whole earth turned to ice. When the anaerobic photosynthesizers died off in the ocean, oxygen spread from the ocean into the atmosphere which changed the climate. Photosynthetic bateria used up more and more CO2 which caused a decrease in temperatures. The aftermath of this ice age caused for almost all life on earth at the time, which was mainly photosynthetic bateria, to die out and this was known as the oxygen catastrophe.

In the Archean Eon, only about 2-3% of the earth's surface was dry land. The earth also may have not even had blue oceans, but green oceans due to an abundance in iron with very little oxygen. Iron reacted with other elements in the water to turn green, while the atmosphere mostly contained nitrogen. New bacteria and photosynthesizers who took in CO2 and released oxygen reacted with the iron in the ocean turning the ocean red.

More about the Archean Eon

After all was said and done with the Huronian Glaciation and the oxygen catastrophe, the world slowly began to flourish again, creating an ozone layer that blocked ultraviolet radiation from the sun, and an abundance of oxygen in the air and water. The Archean Eon was also named after the Greek word for "origin" and this is the eon where life forms began to actually flourish.

References

Grasser, Natalie et al. “Evolution of Earth’s Oxygen, Nitrogen, and Carbon Polar Outflow in the Archean Eon.” Earth and planetary science letters 623 (2023): 118442-. Web. Lepot, Kevin. “Signatures of Early Microbial Life from the Archean (4 to 2.5 Ga) Eon.” Earth-science reviews 209 (2020): 103296-. Web.