Earth's early oxygenation

Trapped gases point to local causes for a famous 2-billion-year-old carbon signal in Russia

Caltech-led researchers say the Shunga-Francevillian carbon signal in Russia's 2-billion-year-old Zaonega rocks can be explained by local processes. That weakens one of the two drill-core records long read as evidence of a planetwide carbon-cycle upheaval.