Earth's mantle holds as much water as oceans, study claims
A group of researchers claims that the middle part of Earth's mantle (410-660 km below the surface) holds as much water as the planet's oceans. Researchers replicated mantle-like conditions in labs and tested water-retaining properties of synthetic minerals found in the mantle. On addition of water, the minerals showed similar fluidity as real measurements, suggesting a water-saturated mid-mantle.