Scientists find a hidden oxygen reservoir in magma deep inside Earth

High-pressure experiments at up to 7 GPa and 1200–1800 °C show that molten mantle rock can hold far more oxygen than its chemical composition suggests, with excess oxygen reaching over 5% of sample weight. The finding hints at a link between Earth's interior and the rise of an oxygen-rich atmosphere.

• At 7 GPa, excess oxygen exceeded 5% of the sample's weight
• Without added PtO2, excess oxygen was only 0.2–0.5% by weight
• 7 GPa is roughly 69,000 times surface atmospheric pressure
• Raman spectroscopy found no gas bubbles, so oxygen entered the glass structure