While the humanity is exploring the outer space and is heading towards the colonization of the planets of our solar system, it turns out that there is still so much to learn about our home planet. A research team led by Dr. Elena Bykova from the University of Bayreuth, Germany, discovered a previously unknown layer in the Earth’s lower mantle which is estimated to contain about eight to ten times more oxygen than the planet’s atmosphere.

“We estimate that this source so far provided an amount of oxygen equivalent to eight to ten times the mass of oxygen in the atmosphere. That’s a surprise, and it is not quite clear what happens with the oxygen down there,” Dr. Bykova said in a press release.

With the help of a special high-pressure chamber, the team was studying the reactions of different types of iron oxide, which is a common component in sedimentary rock formations all over the globe. As a result, it was found that the decomposition of magnetite and hematite under the conditions corresponding to the middle of Earth’s lower mantle (from 1500 to 1670 kilometers under the surface) was accompanied by the release of oxygen-rich fluid in large quantities. Thus, it was concluded that there might be an unknown layer of liquid oxygen in the interior of our planet.

According to the team, there may be entire rivers of liquid oxygen deep under the Earth’s surface. This oxygen either enters into a reaction with surrounding materials or rises to the transition zone or the upper layers of the mantle. Moreover, considering the enormous size of this source of oxygen, it is possible that it can affect geochemical processes and the climate of our planet. At the moment, we have no knowledge about these processes or the origin of the oxygen trapped inside the Earth’s mantle as the findings by Dr. Bykova’s team require further research.

Co-author of the study Dr. Maxim Bykov of the University of Bayreuth explains: “For now, we can only say that there is a huge source of oxygen in the mantle that can significantly affect geochemical processes by changing oxidation states and mobilizing trace elements. This will open a large new field of modelling.”

In fact, it is not the first study to draw surprising conclusions about the interior of our planet. A 2014 study by U.S. researchers found a giant underground “ocean” beneath the Earth’s surface. In particular, it was discovered that the mantle layer of the Earth contains vast reserves of water, which are estimated to be three times greater than the total volume of the world’s oceans. The finding points to the alternative theory which suggests that the oceans emerged from the depths of the early Earth, due to the continuous recycling of tectonic plates.

These two studies remind us that we may not know our planet as well as we think and that it is full of secrets and mysteries that are yet to be revealed.

The results of the study were published in the journal Nature Communications.