Two research studies have discovered a huge ocean 620 miles (1,000 kilometers) below the Earth’s surface, about a third of the way to the Earth’s core. And according to scientists, the deep water is essential to the sustenance of life on the Earth’s surface. If the water dries up, life on the Earth’s surface could go extinct.
The first study, conducted by a team of scientists at Florida State University and the University of Edinburgh in Scotland, and published on the Proceedings of the National Academy of Sciences of the Unites State of America (PNAS), concluded that water exists much deeper beneath the Earth’s surface than previously suspected and that it is stored in a mineral called brucite.
Brucite is a water-holding magnesium hydroxide mineral that carries water deep inside the Earth, where it decomposes and releases the water.
The new study provided evidence for the first time that brucite carries water deeper inside the Earth than previously thought before decomposing to release the water.
While the exact amount of the vast water reserves lurking deep inside the Earth is uncertain, scientists concluded, based on a previous study by researchers from the University of Alberta, that the amount of Earth’s deep water could be about 1.5 percent of the weight of the planet, that is, about the same as water in the oceans that cover about 70 percent of the Earth’s surface.
“We didn’t think water could be stored by hydrous minerals such as brucite at these depths,” said Mainak Mookherjee, who led the study. “But now that we know it’s there, we need to figure out how much water could be effectively stored inside it.”
A separate study led by Dr. Steve Jacobsen at Northwestern University in Evanston, Illinois, came to a similar conclusion: that water exists much deeper than previously suspected, about a third of the way to the Earth’s core.
The water, according to scientists, is essential for the sustenance of life on the surface of the planet because it facilitates geological processes below the Earth’s surface that create volcanoes.
Volcanoes play a vital role in the processes leading to the formation of soil that sustains life on the surface of the Earth.
“Water in the Earth’s interior is crucial since it helps in mantle convection — a process by which solid rocks move from hotter to colder regions over geological time scales,” Mookherjee told the Daily Mail. “If there were no water in the Earth’s interior, mantle convection would be inefficient and would eventually cease. The surface expression of the mantle convection is plate motion/tectonics will also stop.”
“Water clearly has a role in plate tectonics, and we didn’t know before how deep these effects could reach,” he added.
Plate motion or tectonics refers to movements of the Earth’s crust that generate features, such as mountains and volcanoes.
“Volcanoes play an important role in generating the Earth’s crust on which we live,” Mookherjee said. “So if volcanic activity ceases then the crust formation will also stop and the planetary activities will eventually stop.”
According to Jacobsen, who led the study at Northwestern University in Illinois, the deep water probably explains why Earth is the only planet known to exhibit plate tectonics.
Evidence of the existence of a huge store of water about 620 miles below the Earth’s surface was obtained from a diamond discovered near the Sao Luiz river in Juina, Brazil.
The diamond, which is believed to have been ejected from the Earth’s lower mantle through a volcano about 90 million years ago, had a small flaw known as an inclusion. The sealed-off inclusion consisted of minerals trapped inside the diamond during its formation.
Examination of the trapped minerals using infrared microscopy revealed the presence of hydroxyl ions which are normally associated with the presence of water. The types of metals, such as aluminium and titanium, found in the inclusion gave scientists an indication of the depth from which it was ejected.
“This is the deepest evidence for water recycling on the planet,” Jacobsen told New Scientist. “The big take-home message is that the water cycle on Earth is bigger than we ever thought, extending into the deep mantle.”
“If it wasn’t down there, we would all be submerged,” Jacobsen added. “This implies a bigger reservoir of water on the planet than previously thought.”
But despite the description of Earth’s deep water as a vast underground ocean, it is unlike the vast oceans on the surface of Earth that consist of free liquid water.
According to Jacobsen in article published by Smithsonian Magazine, Earth’s deep water is more similar to “milk in cake,” that is, the mineral brucite holds the water in its hydrated form.
Research scientists plan to conduct further research to understand better the behavior of brucite at depths up to 620 miles beneath the Earth’s surface. But scientists remain unable to explain how the huge amount of water stored deep inside the Earth got there. But it is believed the water may have reached the mantle more than 90 million years ago.
Some researchers speculate it came from asteroids, while others believe that Earth has had water since its formation.
It is hoped that scientific evidence of the age of the deep water could help solve the puzzle of the origin of Earth’s water.
[Featured Image by Vadim Sadovski/Shutterstock]