Volcanic activity and mantle changes, key to rise of atmospheric O2 - study

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Oxygen first accumulated in the Earth's atmosphere about 2.4 billion years ago, during the Great Oxidation Event. A long-standing puzzle has been that geologic clues suggest early bacteria were photosynthesizing and pumping out oxygen hundreds of millions of years before then. Where was it all going?

"This study revives a classic hypothesis for the evolution of atmospheric oxygen," said lead author Shintaro Kadoya, a UW postdoctoral researcher in Earth and space sciences. "The data demonstrates that an evolution of the mantle of the Earth could control an evolution of the atmosphere of the Earth, and possibly an evolution of life."

"If changes in the mantle controlled atmospheric oxygen, as this study suggests, the mantle might ultimately set a tempo of the evolution of life," Kadoya said.

"Basically, the supply of oxidizable volcanic gases was capable of gobbling up photosynthetic oxygen for hundreds of millions of years after photosynthesis evolved," said co-author David Catling, a UW professor of Earth and space sciences. "But as the mantle itself became more oxidized, fewer oxidizable volcanic gases were released. Then oxygen flooded the air when there was no longer enough volcanic gas to mop it all up."

Source: https://archaeologynewsnetwork.blogspot.com/2020/06/volcanic-activity-and-changes-in-earths.html

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2020...the year a supervolcano erupts...