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Scientists think they've uncovered evidence of the oldest glaciers ever found, in ancient rocks speckled with oxygen isotopes lying beneath the world's largest gold deposits in South Africa.
STEPHANIE PAPPAS, LIVE SCIENCE
9 APRIL 2021
Earth s transition to permanently hosting an oxygenated atmosphere was a halting process that took 100 million years longer than previously believed, according to a new study.
When Earth first formed 4.5 billion years ago, the atmosphere contained almost no oxygen. But 2.43 billion years ago, something happened: Oxygen levels started rising, then falling, accompanied by massive changes in climate, including several glaciations that may have covered the entire globe in ice.
Chemical signatures locked in rocks that formed during this era had suggested that by 2.32 billion years ago, oxygen was a permanent feature of the planet s atmosphere.
But a new study delving into the period after 2.32 billion years ago finds that oxygen levels were still yo-yoing back and forth until 2.22 billion years ago, when the planet finally reached a permanent tipping point.
Study Finds Drastic Fluctuations in Atmospheric Oxygen After its Early Appearance
Written by AZoCleantechApr 6 2021
A new study reveals that the permanent increase in oxygen in the Earth’s atmosphere, which enabled the emergence of life as it is known, occurred 100 million years later than considered earlier.
Biogeochemist Simon Poulton, left, sprays water on drill core to see sedimentary rocks and select samples for research. Image Credit: Andrey Bekker/UCR.
A major increase in oxygen happened nearly 2.43 billion years ago, which marked the beginning of the Great Oxidation Episode a crucial moment in Earth’s history.
An international team of scientists, including a researcher from UC Riverside, investigated rocks from South Africa formed at the time of this event.