Biosphere expansion drives Earth’s secular oxygenation while tectonics modulate oxygen variability revealed by machine learning

Proceedings of the National Academy of Sciences, Volume 123, Issue 12, March 2026. <br/>SignificanceUnderstanding how Earth’s atmosphere became oxygen-rich is central to uncovering the conditions that allowed geology and life to evolve. Using machine learning and pyrite geochemistry, this study reconstructs atmospheric oxygen levels over the …