Astrobiology article synopsis below.
Full story at: https://www.astrobio.net/biosphere/earths-oxygen-increased-in-gradual-steps-rather-than-big-bursts/
A carbon isotope anomaly found in the Hüttenberg formation of sedimentary rocks in north-eastern Namibia follows a pattern similar to that seen during the Great Oxygenation Event, hinting at new evidence for how Earth’s atmosphere became fully oxygenated.
The study, published in the journal Precambrian Research, paired oxygen , strontium, and sulfur isotope data obtained from drill core samples from the Hüttenberg formation with carbon isotope data published in 2009, providing further evidence that Earth’s oxygen increased in a stepwise fashion, as opposed to being constrained to two major events during the Precambrian.
EMILY C. MOSKAL 