Diamond impurities indicate water flows deep in Earth's mantle too

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It is about one-and-a-half times as dense as the regular ice we use in our drinks. Such arrangement on the Earth can be made only in laboratories. Tschauner and colleagues findings were published today in Science.

The cubic crystalline form of ice, known as ice-VII, is hypothesized to comprise the ocean floor of the Saturn moons of Titan and Europa, as well as planets outside our own solar system.

Scientists have found another kind of water known as Ice VII from diamonds deep in the Earth's outside.

Diamonds can form up to 400 miles beneath the Earth's surface, but materials trapped within them don't always survive up to the surface. The type of ice known as ice VII, is cube-shaped and about 1.5 times denser than normal ice, so-called type-I.

"Usually the extremely deep minerals that come up to the surface are not stable once they experience low pressures", said California Institute of Technology mineralogist and study author George Rossman. "But if a diamond comes up fast enough, it doesn't change". "Ice-VII has recently been recognized as a mineral by the International Mineralogical Association".

Although Science Alert wrote that the inclusions offer the first proof that our planet may be hiding a substantial amount of water deep beneath its surface, the publication stressed that the study did not specify just how much water might exist, or how common the substance may be in those depths. Ice-VII crystallizes as it ascends but it still retains its very high pressure of around 24 gigapascals.

"These discoveries are important in understanding that water-rich regions in the Earth's interior can play a role in the global water budget and the movement of heat-generating radioactive elements", said geoscientist Oliver Tschauner from University of Nevada, Las Vegas.