Earth's water could be mantle-made, meaning it could have originated inside the planet from chemical reactions, or so suggests a study using a computer simulation of reactions in the planet's upper mantle.
The study's researchers said they believe the water-producing reaction takes place under enormous pressure and at about 1,400 Celsius as silicon reacts with liquid hydrogen to form liquid water and silicon hydride, according to New Scientist magazine.
"This is one way water can form on Earth," said John Tse of the University of Saskatchewan in Canada. "We show it's possible to have water forming in Earth's natural environment, rather than being of extraterrestrial origin."
The study by Tse and his collaborators has been published in the journal Earth and Planetary Science Letters.
Researchers suggested in the past that either asteroids or comets brought water to the Earth during collisions, according to Space.com.
Computer simulations in the new study supported work done by Japanese researchers in 2014 pointing to a chemical reaction under various temperatures and pressures typical of the upper mantle from 40 to 400 kilometers, or 25 to 250 miles, down.
"We set up a computer simulation very close to their experimental conditions and simulated the trajectory of the reaction," Tse said, adding that the study showed water forming within quartz that couldn't escape because of built up pressure.
"The hydrogen fluid diffuses through the quartz layer, but ends up forming water not at the surface, but in the bulk of the mineral. We analyzed the density and structure of the trapped water, and found that it is highly pressurized."
In 2014, researchers said they found evidence of "oceans' worth of water" locked up in a type of material called ringwoodite in the mantle's so-called transition zone, which sits between the upper and lower mantle layers 255 to 410 miles below Earth's surface, reported LiveScience.com.
"The transition zone can hold a lot of water, and could potentially have the same amount of H2O (water) as all the world's oceans," said Brandon Schmandt, a seismologist at the University of New Mexico and co-author of the 2014 study.
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