New Evidence Suggests Earth Has Vast Subterranean Oceans

[Kazimiera]

New Evidence Suggests Earth Has Vast Subterranean Oceans

http://www.iflscience.com/sites/www.iflscience.com/files/styles/ifls_large/public/blog/%5Bnid%5D/WEB_1_Pearson_et_al_Diamond-NATURE-PRESS-IMG.jpg?itok=bDAtjE2B
This tiny stone holds the first specimen of a rock that makes up most of the Earth 600km down

It sounds like something from one of those cranks who believe the Earth is hollow, or a mash-up between Jules Verne's classics Journey to the Centre of the Earth and Twenty Thousand Leagues Under the Sea, but University of Alberta scientists claim to have evidence of a vast waterbody 500km beneath our feet.

The evidence for such a large claim is rather small – a few micrograms of water trapped inside a single gem, but according to Dr Graham Pearson, “That particular zone in the Earth, the transition zone, might have as much water as all the world’s oceans put together.”

Ringwoodite is named for Dr Ted Ringwood, an expert in the transformations that occur in certain rocks at high prssures. He showed that olvine (Mg, Fe)2SiO4 could take on a different crystal structure under enormous pressure and predicted that at great depths beneath the Earth's surface this would occur. Natural ringwoodite was first found in meteorites, rather than escapees from the deep.

It is thought that Ringwoodite is the most common mineral at depths of 520-660km, known as the lower transition zone, and that its properties shape the mantle's flow at these depths. Laboratory experiments have shown it can contain up to 2.6% water, but with no previous terrestrial examples geologists could only speculate as to how much might be absorbed here.

Pearson's ringwoodite was found in river gravel in Mato Grosso Brazil. The area is rich in diamonds brought up from the depths in kimberlite, a volcanic substance with the deepest origins of any rock commonly found at the surface. When ringwoodite rises from the enormous pressures below 520km it changes form to first wadsleyite and then olivine, but if trapped inside a diamond it keeps its original structure.

Pearons was looking for something else but was offered a brown diamond, too dirty-looking to have commercial value and weighing a tenth of a gram. Within this small stone is buried a 0.04mm piece of ringwoodite noticed by Pearson's student John McNeil, leading to publication in Nature. "It's so small, this inclusion, it's extremely difficult to find, never mind work on," Pearson said, "so it was a bit of a piece of luck, this discovery, as are many scientific discoveries."

After years of study with X-Ray diffraction and infrared spectroscopy its status as Ringwoodite was confirmed and the water content tested, returning a result of 1.5% by weight.

There are competing theories about whether the Earth at these depths is rich in water, or mostly dry. While the presence of water in Pearson's stone indicates the presence of water where it formed, the find may not be sufficient to convert those who believe in a dry transition zone to the theory that water is common at these depths. Professor Norm Sleep of Stanford University told Nature that even if you find a nugget of gold in a riverbed, “It would be unwise to assume that all the gravel in the stream is gold nuggets,”

Nevertheless, Pearson feels vindicated. "One of the reasons the Earth is such a dynamic planet is the presence of some water in its interior," Pearson said. "Water changes everything about the way a planet works."


Source: http://www.iflscience.com/chemistry/new-evidence-suggests-earth-has-vast-subterranean-oceans

[Yehiel]

Tanakh says there is water beneath the earth...

[Melina]

Today I read that there is more evidence that the world may be hollow. The earths composition which I studied in elementary school seems to not be valid anymore.

http://www.scmp.com/news/world/article/1533108/vast-ocean-trapped-under-core-earth-scientists-say


If you want to find earth’s vast reservoirs of water, you may have to look beyond the obvious places like the oceans and polar ice caps. Scientists say they have found a vast reservoir of water – enough to fill the world’s oceans three times over – trapped up to 660km beneath the crust of the earth, potentially transforming our understanding of how the planet was formed.

But do not expect to quench your thirst down there. The water is not liquid – or any other familiar form like ice or vapour. It is locked inside the molecular structure of minerals called ringwoodite and wadsleyite in mantle rock that possesses the remarkable ability to absorb water like a sponge.

“It may equal or perhaps be larger than the amount of water in the oceans,” said Northwestern University geophysicist Steve Jacobsen, who co-authored a study in the journal Science. “It alters our thoughts about the composition of the earth.”

He said the finding suggested the earth’s water may have come from within, driven to the surface by geological activity rather than being deposited by icy comets hitting the forming planet.

“I think we are finally seeing evidence for a whole-earth water cycle, which may help explain the vast amount of liquid water on our planet,” he said.

Jacobsen and his colleagues are the first to provide direct evidence that there may be water in an area of the Earth’s mantle known as the transition zone. They based their findings on a study of a vast underground region extending across most of the interior of the United States.

Scientists used data from the USArray – a network of seismometers across the US that measures the vibrations of earthquakes – and a series of laboratory experiments on rocks simulating the high pressures found more than 600km underground.

It produced evidence that the melting and movement of rock in the transition zone led to a process where water could become fused and trapped in the rock.

The discovery is remarkable because most melting in the mantle was previously thought to occur at a much shallower distance, about 80km below the earth’s surface.

“If [the stored water] wasn’t there, it would be on the surface of the earth, and mountaintops would be the only land poking out,” he said.

[Smaug]

Fantastic, if that's true. I wonder what's the depth these oceans would reach, or if the water in them is too hot, but doesn't boil because of high pressures.