Where Did the Oceans Come From?
Scientists have long pondered where the Earth’s water came from. Common hypotheses include that it arrived on meteorites or that it gradually oozed up from inside of the Earth’s mantle.
Recent evidence supports the latter claim after scientists discovered traces of water in certain minerals from within the transition zone deep inside the planet.
Could there be an entire massive “ocean,” hundreds of miles below our feet? These researchers think so.
And it all has to do with this tiny mineral…
Ringwoodite is a blue mineral that exists naturally some 440 miles deep in the Earth’s mantle.
Believed to be most present in the mantle’s transition zone, ringwoodite is the result of olivine in the upper mantle polymorphing as it sinks downward into higher temperature and pressure zones.
Though the only naturally-occurring, terrestrial sample of ringwoodite was found in a diamond that came to the surface in a type of volcano in Brazil, scientists have conducted research on synthetic ringwoodite and tested it at transition zone pressures and temperatures to prove one major thing:
Ringwoodite is capable of holding up to 1.5–2.6 percent by weight water.
At transition zone conditions in the lab, ringwoodite has been shown to trap water as hydroxide ions. This could be the proof scientists needed that there is, in fact, massive amounts of water beneath the Earth’s crust, so researchers did further tests on ringwoodite to learn more about the planet’s mantle.