The high water content of the transition zone has far-reaching consequences (Representative Image)
According to an international study, scientists have discovered a reservoir under the Earth’s surface three times larger than the volume of all oceans. Water is found between the transition zone of the Earth’s upper and lower mantle. According to ANI, the research team used techniques including Raman spectroscopy and FTIR spectrometry to analyze the diamond, which was formed 660 meters below the Earth’s surface.
The study confirmed what had long been just a theory, namely that ocean water accompanies subducting plates and thus enters the transition zone. This means that the water cycle of our planet covers the interior of the Earth.
Prof. Frank Brenker of the Geological Institute of the Goethe University in Frankfurt. For example, mantle plumes—columns of hot rock rising from the deep mantle—sometimes rest directly beneath the transition zone. The movement of the mass in the opposite direction also stops.
“Igneous plates often have trouble crossing the entire transition zone,” says Brenker. “So there’s a whole graveyard of such plates in this zone beneath Europa.”
However, until now it was not known what the long-term effect of the material “soaked” into the transition zone was on its geochemical composition, and whether there was a larger amount of water there. Brenker explains: “Subducting plates also transport deep-sea sediments into the Earth’s interior. These sediments can store large amounts of water and CO2. But until now it was not clear how much of the transition zone entered the transition zone in stable form. Hydrous minerals and carbonates – and therefore there It was also unclear whether large amounts of water were actually stored.”
Of course, the current conditions will make it possible. The dense minerals wadsleyite and ringwoodite (as opposed to olivine at shallower depths) can hold large amounts of water—so large, in fact, that the transition zone theoretically absorbs six times the amount of water in our oceans. “So we knew that the boundary layer had a great capacity to hold water,” Brenker said. “But we didn’t know if that was really the case.”
An international study involving a Frankfurt geoscientist has now provided the answer. The research team analyzed a diamond from Botswana, Africa. It formed at a depth of 660 kilometers at the boundary between the transition zone and the lower mantle, where ringwoodite is the dominant mineral. Diamonds from this region are very rare, even among super-deep origin rare diamonds that only account for one percent of diamonds. Analysis revealed that the stone contained many ringwoodite inclusions — which indicate a high water content. In addition, the research team was able to determine the chemical composition of the stone. It was identical to almost every fragment of mantle rock found in basalts almost 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 demonstrated that the transition zone is not a dry sponge, but holds a significant amount of water,” said Brenker, adding: “This brings us one step closer to Jules Verne’s idea of an ocean within an ocean. Earth.” The difference is that there is no ocean, but according to Brenker, there is watery rock that feels neither wet nor dripping water.
