15 Feb 2016

At http://phys.org/print373313880.html ... scientists have discovered two new iron oxides in experiments. These seem to point to a huge, hitherto unknown oxygen source in the lower mantle of the earth. Published in Nature Communications (Feb 2016) Elena Bykova estimated an amount of oxygen equivalent to 8 or 10 times the mass of oxygen in the atmosphere. That is a surprise, she said, and we don't know what happens or what is going on with the oxygen in the lower mantle.