Deep-Earth minerals could cradle oceans of water far beneath the crust
A Nature Geoscience study identifies two newly discovered iron oxyhydroxide minerals that could trap vast amounts of water deep in the lower mantle, around 2,900 kilometres below the surface near the mantle–outer core boundary. If confirmed, this suggests water equivalent to about one to two Pacific Oceans might reside inside Earth, though the evidence is preliminary and the water would be stored within minerals rather than as liquid oceans.