"At about what time will the polar caps melt and when they do will it flood the earth?"
Content with the tag: “early atmosphere”
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Oxygen's Stops and Starts
Panorama of Russia's Imandra/Varzuga Greenstone Belt where FAR DEEP drilling took place. Credit: Victor Melezhik, Geological Survey of Norway/University of Bergen
Based on studies of rock cores, geoscientists supported in part by the NASA Astrobiology Institute have determined that oxygen did not appear in Earth’s atmosphere in a single event. Instead, atmospheric oxygen came about in a long series of starts and stops.The research was conducted using samples collected in the summer of 2007 during the Fennoscandia Arctic Russia – Drilling Early Earth Project (FAR DEEP). Scientists drilled a series of shallow, two-inch diameter cores and overlapped them to create a record of the Proterozoic Eon—2,500 million to 542 million years ago.
“We’ve always thought...
Source: [National Science Foundation]
December 8, 2011 / Posted by: Aaron Gronstal
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Evidence for the Great Oxidation Event Challenged
The timing of the rise of oxygen in Earth’s atmosphere is a key question in astrobiology. It is coupled not only to the question of when organisms capable of oxygenic photosynthesis first evolved on Earth, but also what signs of life might be found on young Earth-like planets around other stars.
Members of NAI’s Penn State and Carnegie Institution of Washington Teams report in the current issue of Science that certain sulfur isotopes found in many sedimentary rocks older than 2.4 billion years may not be the result of photochemical reactions in an oxygen-free atmosphere as previously thought....
April 17, 2009 / Posted by: Daniella Scalice
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