Massive ‘ocean’ was discovered toward Earth’s core. A reservoir of water three times the volume of all the oceans has been discovered deep beneath the Earth’s surface. The finding maybe help explain where Earth’s seas came from.
The water is hidden inside a blue rock called ringwoodite lying 700 kilometres underground in the mantle, the layer of hot rock between Earth’s surface and its core.
This water could indicate the largest water reservoir on the planet. It is bound up in rock. It is believed that plate tectonics cycle the water in and out, and the water affects the partial melting of rock in the mantle.
Four hundred miles beneath North America, Schmandt and Jacobsen found deep pockets of magma, which indicates the presence of water. However, this isn’t water in any of the three forms we are familiar with. The pressure coupled with the high temperatures forces the water to split into a hydroxyl radical (OH) which is then able to combine with the minerals on a molecular level.
“Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” said Jacobsen in a press release. “I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”
“Whether or not this unique sample is representative of the Earth’s interior composition is not known, however,” Jacobsen said. “Now we have found evidence for extensive melting beneath North America at the same depths corresponding to the dehydration of ringwoodite, which is exactly what has been happening in my experiments.”
The huge size of the reservoir throws new light on the origin of Earth’s water. Some geologists think water arrived in comets as they struck the planet, but the new discovery supports an alternative idea that the oceans gradually oozed out of the interior of the early Earth.
“It’s good evidence the Earth’s water came from within,” says Steven Jacobsen of Northwestern University in Evanston, Illinois. The hidden water could also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years.”