Scientists Just Discovered a Vast Ocean Trapped 700 Km Beneath Earth’s Surface

Key Points:

• Scientists have discovered a massive reservoir of water trapped about 700 kilometers below Earth’s surface within the mantle’s transition zone, potentially holding three times the volume of all the planet’s oceans combined.
• This water is bound within the mineral ringwoodite, which absorbs water at the molecular level under extreme mantle pressures, creating a sponge-like effect that stores vast amounts of water deep underground.
• Using seismic data from over 500 earthquakes and 2,000 seismographs, researchers mapped slower-moving seismic waves indicative of wet rock, providing strong evidence that Earth’s water partly originates from internal sources rather than solely from extraterrestrial impacts.
• The discovery extends the concept of the water cycle deep into the mantle, where water is recycled through subduction zones and volcanic activity, helping to maintain stable ocean levels over hundreds of millions of years.
• Future research aims to investigate whether water-rich ringwoodite is widespread globally, refine estimates of the mantle’s water content, and better understand how this deep reservoir influences Earth’s geology, plate tectonics, and long-term ocean stability.