There is more freshwater locked inside the rocks of Earth's mantle than in every river, lake, and surface reservoir on the planet combined, hidden in a mineral called ringwoodite hundreds of miles ben
Space Daily • • science
Key Points:
- Earth's largest water reservoir is hidden deep in the mantle transition zone (410-660 km beneath the crust) within the mineral ringwoodite, which may hold more water than all surface freshwater combined.
- This discovery was confirmed by a microscopic ringwoodite inclusion inside a diamond from Brazil, which contained hydroxyl groups bound in the crystal lattice, indicating significant water content at depth.
- The mantle transition zone acts as a hydrogeological trap, storing water in minerals like ringwoodite and wadsleyite, which release water as they transform at greater depths, influencing mantle melting and seismic properties.
- Seismic studies support the presence of a hydrated transition zone by detecting partial melt consistent with water release at the 660-kilometre boundary, linked to subduction processes transporting water deep into Earth.
- Although this deep mantle water is chemically freshwater, it is inaccessible for human use and instead plays a crucial role in regulating Earth's long-term water cycle and planetary habitability.