Nepal, Aug. 28 -- An international team of researchers has revealed how Earth's atmosphere transformed from oxygen-poor to oxygen-rich over about 2 billion years.

The team reconstructed the rise of atmospheric oxygen and its dynamic interplay with the oceans by analyzing high-resolution oxygen isotope records preserved in ancient sulphate minerals, according to a statement released 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 Paleozoic (538.8 to 252 million years ago) eras, culminating in stable, modern-like levels about 410 million year...