Earth's big oxygen boost pushed back

摘要

The breath of oxygen that enabled the emergence of complex life kicked off around 100 million years earlier than previously thought, new dating suggests. Previous studies pegged the first appearance of relatively abundant oxygen in Earth's atmosphere, known as the Great Oxidation Event, at a little over 2.3 billion years ago. But new dating of ancient volcanic outpourings suggests that oxygen levels began a wobbly upsurge by 2.426 billion years ago, scientists report online February 6 in Proceedings of the National Academy of Sciences.