Pushing back an oxygen-rich atmosphere

Hematite crystals in Australian rocks hint that photosynthesizing life may have existed earlier than previously thought

By Sid Perkins, 15:47 PM March 13, 2009

Tiny crystals of iron oxide in ancient Australian rocks offer evidence that the Earth’s atmosphere held significant amounts of oxygen far earlier than previously thought, a new study suggests.

Large quantities of oxide minerals in rocks around the world indicate that the atmosphere had at least small amounts of oxygen by 2.2 billion years ago (SN: 1/24/04, p. 61). And the presence of certain biomarkers in Australian rocks has been hailed as evidence that oxygen-making organisms had evolved ...

Source URL: https://www.sciencenews.org/article/pushing-back-oxygen-rich-atmosphere?mode=magazine&context=679