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: The Earth 's oxygen levels have increased and decreased more than a hundred million years before the global success of the Great Oxidation Event, there are about 2.4 billion of them. 39; years. The researchers said the researchers had confirmed the appearance of oxygen in the Earth's past about 150 million years ago. or about 2.66 billion years ago – and for less than 50 million years.
The team badyzed samples taken by Roger Buick, professor at the University of Washington, in 2012 in another site in northwestern Australia. Jeerinah training. The badysis of successive layers in the rocks shows, according to Buick, a "gradual" change in nitrogen isotopes, and then returns to zero
Nitrogen isotopes reveal the & 1965 [19651965196519651965196519651965196519651965196519651965196519651965196519651965196519651965activityofsomemarinemicroorganismsthatuseoxygentoformnitratesandothermicroorganismsusethisnitrateforenergy
Data collected from nitrogen isotopes sample the surface of the ocean, while selenium suggests oxygen in the air of the ancient Earth. Koehler said that the deep ocean was probably anoxic, or without oxygen, at the time. The team found abundant selenium in the shallow hole only, which meant that it came from nearby lands, not allowing to reach the deeper waters.
Selenium is retained in sulphide minerals on land; the higher atmospheric oxygen would cause a greater amount of selenium from the earth by oxidation – "rust rocks", and transported to the sea, Buick said.PTI
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