Researchers performed Raman spectral analysis on samples from nine geological formations dating from 742 to 1729 million years ago and used the extent of organic matter recycling as a proxy for atmospheric oxygen levels during the Proterozoic Eon; the study estimates that minimum oxygen levels during the Proterozoic Eon were 2-20% of present levels, suggesting that oxygen levels likely did not hinder the evolution of eukaryotes and early animals during this time.
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Article #2021-01544: "Petrographic carbon in ancient sediments constrains Proterozoic Era atmospheric oxygen levels," by Donald E. Canfield et al.
MEDIA CONTACT: Donald E. Canfield, University of Southern Denmark, Odense, DENMARK; tel: (45) 65 50 27 51; email: dec@biology.sdu.dk
Proceedings of the National Academy of Sciences