A group of American researchers have discovered a gigantic ocean that its between the earth’s crust and core where large reserves of water, about three times as much as on the surface, rests.
Led by Steven Jacobsen of Northwestern University and Brandon Schmandt of the University of New Mexico, the researchers discovered that the water is molecularly trapped inside a mineral called ringwoodite.
This discovery sheds some light on how our oceans formed and maintained their size over millions of years. Most geologists think that water came from space in the form of icy comets, but this new discovery suggests that oceans may have gradually emerged from the depths of the early Earth. “The indications show that the Earth’s water came from inside,” said Jacobsen. Researchers used 2,000 seismographs to study the seismic waves of some 500 earthquakes and measured their velocity at different depths. These waves moved at different speeds through water than through rocks.
“When a rock with a lot of H2O moves from the transition zone to the lower mantle it needs to get rid of the H2O somehow, so it melts a little bit. This is called dehydration melting,” said Brandon Schmandt.
The study was published in the journal Science.