The idea of an underwater world has fueled much science fiction, but a group of researchers say it’s not too far off scientific fact. They have discovered an area within the Earth’s surface that is believed to contain far more water than the rest of the Earth’s oceans combined. The find was sparked by the discovery of a diamond and may support a theory that has shattered conventional wisdom about how water formed on the planet. Read on to find out what the scientists found and what implications it could have.
at Goethe University In Frankfurt, Germany, geoscientists examined a diamond found more than 2,100 feet below the surface in Botswana, Africa. Analyzing the contents of the stone, they found that it contained a large amount of water. The large volume of water in the diamond is evidence that supports a theory — which was previously just a theory — that a vast ocean floats deep in the planet’s crust between the upper and lower layers of the Earth.
The depth at which the diamond was found — 660 meters, or about 2,100 feet — is in the deepest part of the “transition zone,” the boundary layer that separates Earth’s upper mantle from the lower mantle. Minerals found in areas deeper in the transition zone — closer to the Earth’s core — are denser and less likely to move closer to the Earth’s surface like the tectonic plates. “These mineral transformations severely impede the rock movements in the mantle,” said Prof. Frank Brenker from the Institute for Geosciences at the Goethe University in Frankfurt. For example, mantle plumes — rising columns of hot rock from the deep mantle — sometimes terminate just below the transition zone. The mass movement in the opposite direction also comes to a standstill.” Because of the density and statics of this zone, scientists weren’t sure how much water was there.
Until they analyzed the diamond. Using advanced spectroscopy, the researchers found that the diamond contained ringwoodite, a mineral with a high water content. “We have shown in this study that the transition zone is not a dry sponge but contains considerable amounts of water,” says Brenker. “This also brings us a step closer to Jules Verne’s idea of an ocean inside the earth.”
Scientists had previously theorized that the transition zone could potentially contain six times the amount of water of all the planet’s oceans, as minerals found deep in the Earth’s crust — wadsleyite and ringwoodite — could store large amounts of water. “So we knew that the boundary layer has enormous water storage capacity,” says Brenker. “But we didn’t know if that was really the case.” Until now. It could be evidence that water deep within the Earth is part of the planet’s overall water system.
The discovery could join others in revising ideas about where Earth’s water came from. The prevailing theory is that the young planet was too hot for water to evolve naturally. It is believed that water was formed further out in the solar system and then brought to the planet by comets or asteroids that crashed onto the surface. But if water existed deep in the planet’s transition zone, this theory will not hold.