Posted By: Susoni [Send E-Mail]
Date: Saturday, 15-Mar-2014 21:30:11
The graphic is misleading people, it's not a literal ocean beneath an ocean. All that water is bound up in crystal lattices or porous rock...
In what sounds like a chapter from Journey to the Center of the Earth, the chemical makeup of a tiny, extremely rare gemstone has made researchers think there's a massive water reservoir hundreds of miles under the earth.
The gemstone in question is called ringwoodite, which is created when olivine, a material that is extremely common in the mantle, is highly pressurized; when it’s exposed to less pressurized environments, it reverts into olivine. It has previously been seen in meteorites and created in a laboratory, but until now it had never been found in a sample of the earth’s mantle.
Diamond expert Graham Pearson of the University of Alberta came across a seemingly worthless, three-millimeter piece of brown diamond that had been found in Mato Grosso, Brazil, while he was researching another type of mineral. Within that diamond, he and his team found ringwoodite—and they found that roughly 1.5 percent of the ringwoodite’s weight was made up of trapped water. The findings are published in Nature.
That water had to get in there somehow, and using analyses of its depth and its water makeup, Pearson suggests that there's water deep under the earth's surface—a lot of it.
The finding “confirms predictions from high-pressure laboratory experiments that a water reservoir comparable in size to all the oceans combined is hidden deep in Earth’s mantle,” according to an analysis of Pearson’s findings by Hans Keppler of the University of Bayreuth in Germany.
The earth’s crust, including the deepest parts of the oceans, reach depths of roughly 100 kilometers. From there, the upper mantle takes up about another 300 kilometers. Between there and the lower mantle is where this piece of ringwoodite was originally from—an area between 410 and 660 kilometers beneath the earth’s surface known as the “transition zone.”
Scientists have long been divided about what, exactly, is in the transition zone. We’ve known that much of the upper mantle is made up of olivine, and as Keppler said, scientists have long thought that Earth contained reservoirs of water deep beneath the crust. But they weren’t sure whether the water existed as low as the transition zone—the area between the upper and lower mantles. While some say that much of the oceans’ water may have originated there, others have said it is likely completely dry.
Link for this article：:http://www.vice.com/en_au/read/theres-an-ocean-deep-inside-the-earth-mb-test