MEDIA RELEASE: R00155 – 20 July 2016
A Brock University-led international research team has discovered a new way of measuring past oxygen levels on Earth: by tapping into the actual air that existed almost a billion years ago.
Up until now, scientists estimated that oxygen comprised no more than two per cent of the Earth’s atmosphere 800 million to one billion years ago.
But the team found that the average oxygen content of the Earth’s atmosphere was 10.9 per cent, more than five times greater than previously thought and about half of today’s oxygen level.
“There was a lot of debate as to what the oxygen content was 800 million or more years ago,” says Professor of Earth Sciences Nigel Blamey. “We’ve come up with a direct method of analyzing the content of those trapped fossil gasses in the atmosphere and found that the oxygen level was approximately half of what it is today.”
Blamey used a custom-built machine to crush samples of ‘halite,’ which is the natural form of table salt.
Within the halite samples are tiny bubbles that contain atmospheric gasses that were trapped in the rocks at the time they formed. But until now, the bubbles were too small to measure. The equipment was able to read and analyze the trapped fossil gasses.
This new approach, and the subsequent findings, have huge implications for theories on the development of life on Earth, say the researchers. Scientists’ understanding of Earth’s early life forms are based in part on the amount of oxygen believed to be in the atmosphere at that time.
The team’s findings shed light on more than just the evolution of life forms.
“Deciphering the oxygenation history of the atmosphere and oceans is critical to understanding weathering processes, sedimentary environments, climate change, mass extinctions, tectonic events, and the evolution of Earth’s biota,” says the team’s study.
The measuring process and findings can also help determine the evolution of life on Mars and other planets, says Professor of Earth Sciences Uwe Brand.
“This will give us a better understanding of how life evolved,” he says.
The study, titled “Paradigm shift in determining Neoproterozoic atmospheric oxygen,” is scheduled to appear in the August edition of Geology, the monthly journal of the Geological Society of America. An advanced summary of the paper can be found here.
For more a detailed explanation of the testing equipment and the research implications, see the story in The Brock News.
Downloadable audio clips with Blamey and Brand talking about the research can be found on Soundcloud.
Both Blamey and Brand are available for interviews with the media.
For more information or for assistance arranging interviews:
* Dan Dakin, Media Relations Officer, Brock University ddakin@brocku.ca,
905-688-5550 x5353 or 905-347-1970
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