SYDNEY - An international team of researchers has uncovered how Earth's atmosphere transformed from being oxygen-poor to oxygen-rich over a span of about two billion years, reported Xinhua.
The team traced the rise of atmospheric oxygen and its dynamic interplay with the oceans by analysing high-resolution oxygen isotope records preserved in ancient sulphate minerals, according to a statement released on Thursday by the University of Western Australia (UWA).
Their study revealed three major episodes of atmospheric oxygen increase, during the Paleoproterozoic (2,500 to 1,600 million years ago), Neoproterozoic (1,000 to 538.8 million years ago), and Palaeozoic (538.8 to 252 million years ago) eras, culminating in stable, modern-like levels about 410 million years ago.
"The rise of oxygen in Earth's atmosphere is fundamental to the emergence of oxygen-breathing complex life, planetary habitability and the creation of vital natural resources," said Matthew Dodd from the UWA's School of Earth Sciences.
The study, led by China's Chengdu University of Technology in collaboration with UWA and published in Nature, found that after the Neoproterozoic oxygen rise, Earth's mostly oxygen-poor oceans underwent periodic pulses of oxidation.
These events resulted in synchronised shifts in carbon, sulphur, and oxygen isotopes over hundreds of millions of years, which suggests that increasing atmospheric oxygen repeatedly triggered temporary episodes of ocean oxidation.
"The findings provide an environmental framework for understanding the origin and evolution of life on Earth, as well as the formation of mineral deposits and petroleum resources," Dodd said. - BERNAMA-XINHUA