Time line showing how oxygen concentrations in the Earth's atmosphere have changed (IMAGE)

University of Leeds

Time line showing how oxygen concentrations in the Earth's atmosphere have changed

Caption

A rough outline of oxygen (O2) concentrations in Earth's atmosphere through time are illustrated in this figure. Brown blocks show the estimated range for O2 in terms of its present atmospheric level (which is 21% by volume). Grey-blue lines indicated various important events for the evolution of life, including the emergence of eukaryotes and animals. Black arrows refer to important events where atmospheric oxygen concentration changed. The Archean, Proterozoic, and Phanerozoic are geological eons. GOE = Great Oxidation Event; NOE = Neoproterozoic Oxidation Event; CE = Cambrian Explosion; LE = Lomagundi Excursion.

Credit

Please credit: Gregory Cooke/ Royal Society Open Science

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License

CC BY

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