Produced by: Mohsin Shaikh
Representative pic
Beneath your feet, 400 miles down, lies an ocean’s worth of water—not in liquid form, but locked inside the crystal lattice of a rare blue mineral called ringwoodite. It’s a hidden reservoir that rivals all Earth’s surface oceans.
Representative pic
Ringwoodite acts like a sponge under crushing pressure, absorbing water into its structure. Scientists say it could hold up to 1.5% of its weight in water—enough to alter our entire understanding of Earth’s water cycle.
Molten rock discovered 400 miles below North America stunned geologists. Most melting happens far shallower—so what’s heating it? The answer: water, released from ringwoodite as it dehydrates deep underground.
Think the water cycle ends with clouds and rain? Think again. This new study reveals a whole-Earth water cycle where oceans, volcanoes, and tectonic plates are all linked through deep-earth processes we’re only beginning to map.
Subduction zones are more than plate graveyards—they’re pipelines. As crust plunges into the mantle, water-rich minerals like ringwoodite hitch a ride down, then melt and release water back up through eruptions and earthquakes.
Why does Earth have so much surface water, unlike its rocky neighbors? This buried ocean may be the reason—an ancient, internal reservoir that slowly feeds life above without us ever seeing a drop.
Lab tests confirmed it: ringwoodite stores water under mantle-like heat and pressure. It's not liquid, but hydroxyl-rich rock. Still, the implications are enormous—from earthquake mechanics to volcano triggers.
Seismic waves sweeping through the mantle don’t just reveal rock—they reveal water. Slower wave speeds spotted by the USArray suggest partially melted rock, right where ringwoodite would be losing its grip on water.
If Earth hides this much water inside, what about other planets? Could Mars or Venus once have had similar reservoirs—and lost them? This discovery doesn’t just change geology; it deepens the mystery of planetary evolution.