Volcanism and global glaciation coincided to the gas’s rise
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, or GOE, at a little over 2.3 billion years ago. New dating of ancient volcanic outpourings, however, suggests that oxygen levels began a wobbly upsurge between 2.460 billion and 2.426 billion years ago, researchers report the week of February 6 in Proceedings of the National Academy of Sciences.
That time difference is a big deal, says study coauthor and sedimentary geologist Andrey Bekker of the University of California, Riverside. The new date shakes up scientists’ understanding of the environmental conditions that led to the GOE, which prompted the evolution of oxygen-dependent life-forms called