Archean Earth’s Upper Atmosphere Was Oxygen-Rich, Scientists Discover

[Newsman]

An international team of researchers from Australia and the United Kingdom has made a surprising discovery about the chemistry of Earth’s upper atmosphere in the Archean era, about 2.7 billion years ago.

The study, led by Monash University scientist Andrew Tomkins, indicates that Archean Earth’s upper atmosphere contained about the same amount of oxygen as today, and that a methane haze layer separated it from an oxygen-starved lower atmosphere.

These findings, published in the May 12 issue of the journal Nature, challenge the accepted view that Earth’s atmosphere was oxygen poor 2.7 billion years ago.

“It is widely accepted that Earth’s early atmosphere contained less than 0.001% of the present-day atmospheric oxygen level, until the Great Oxidation Event resulted in a major rise in oxygen concentration about 2.4 billion years ago,” Dr. Tomkins and co-authors said.

http://www.sci-news.com/othersciences/p ... 03859.html