Ringwoodite is an extremely rare gemstone, which is a highly-pressurized form of a material called Olivine. So, when Ringwoodite is exposed to low pressure, it turns into Olivine. Ringwoodite has previously been found in meteorites and prepared inside laboratories. Olivine is very common underground but no one had ever found any evidence of Ringwoodite in the earth’s mantle.
Graham Pearson and his team, from University of Alberta, were studying a worthless brown diamond and trying to find out its age somehow by the minerals present inside it, when they actually found the inclusion of the rare Ringwoodite. And here’s the interesting thing, 1.5% of the Ringwoodite’s weight was water. According to Pearson,
That doesn’t sound like much, but when you calculate the vast volumes of Ringwoodite thought to exist in the deep Earth, the amount of water might be as high as that contained in all the world’s oceans.
Which is estimated to be 1 billion billion tons of water. This isn’t anything like Jules Verne’s Journey to the Center of the Earth, the water is held within the transition zone. The transition zone is a 250KM layer between the outer and inner mantle. The emphasis of this discovery is the Ringwoodite has been found inside the earth’s mantle for the first time. The predictions have always been there but this is the first time a sample has actually been found. You might wonder, why don’t they just go directly to the transition zone or drill to that layer like they do in cartoons. This is no small task. Pearson says,
No one is ever going to run a geological field trip to the transition zone 500km beneath the Earth’s surface, and no one is ever going to drill down to the transition zone. It was a total piece of luck that we found this.
That water in the structure got there somehow, and using analyses of its depth and its water makeup and the chemical structure, Pearson concludes that there is a lot of water inside the earth, probably more than all the oceans on outer surface combined. The specifics to how this conclusion was made are published in the journal, Nature.
This may also provide more explanations for phenomena like eruptions and uplifts. The original scarred brown diamond, probably shot up to the surface by an eruption of a molten rock called kimberlite.
This may all may not sound like a big deal but this “Water inside the Earth” is a huge leap in geology.