Scientists have discovered a reservoir of water that is three times larger than the volume of all the oceans below the Earth’s surface, according to an international study. Water was found between the transition zone of the Earth’s upper and lower mantle.
The research team analyzed the speed diamond formed 660 meters below the earth’s surface using techniques including Raman spectroscopy and FTIR spectrometry, ANI reported.
The study confirmed something that had long been only a theory, namely that ocean water accompanies subducting plates and thus enters the transition zone. This means that the water cycle of our planet includes the interior of the Earth.
“These mineral transformations greatly hinder the movement of rock in the mantle,” explains prof. Frank Brenker of the Institute for Geosciences at Goethe University Frankfurt.
For example, mantle plumes—rising columns of hot rock from the deep mantle—sometimes stop just below the transition zone. The movement of mass in the opposite direction also stops.
Brenker says, “Subducting plates often have trouble breaking through the entire transition zone. So there’s a whole graveyard of such plates in this zone beneath Europe.”
Until now, however, it was not known what the long-term effects of “sucking” material into the transition zone are on its geochemical composition and whether there is a greater amount of water there.
Brenker explains: “Subducting plates also transport deep-sea sediments into the Earth’s interior. These sediments can hold large amounts of water and CO2. But until now, it was not clear how much enters the transition zone in a more stable form.
” hydrous minerals and carbonates – and therefore it was also unclear whether a large amount of water was actually stored there.’
Prevailing conditions would certainly help this. The dense minerals wadsleyite and ringwoodite can (unlike olivine at shallower depths) store large amounts of water – so much, in fact, that the transition zone would theoretically be able to absorb six times the amount of water in our oceans.
“So we knew that the boundary layer has a huge capacity to store water,” says Brenker. “But we didn’t know if that was really the case.”
The answer has now been provided by international studies in which the Frankfurt geoscientist participated. The research team analyzed a diamond from Botswana, Africa. It was formed at a depth of 660 kilometers, right at the interface of the transition zone and the lower mantle, where ringwoodite predominates.
Diamonds from this area are very rare, even among the rare super-deep origin diamonds that make up only one percent of diamonds. Analyzes revealed that the stone contains numerous ringwoodite inclusions – which exhibit a high water content.
Furthermore, the research group managed to determine the chemical composition of the stone. It was almost exactly the same as virtually every fragment of mantle rock found in basalts anywhere in the world. This showed that the diamond definitely came from a normal piece of the Earth’s mantle.
“In this study, we have shown that the transition zone is not a dry sponge, but contains a significant amount of water,” Brenker says, adding: “This also brings us one step closer to Jules Verne’s idea of an ocean inside the Earth.”
The difference is that there is no ocean down there, but moist rock, which, according to Brenker, would be neither wet nor dripping with water.