The center of the Earth is a complete mystery to geologists who are slowly trying to unveil its secrets. New research suggests that carbon, which is known to be of great importance to the planet’s cycles, may be releasing diamonds into the Earth’s core, meaning that some of these precious stones may exist in certain regions of the deep mantle.
Carbon transfer between the core and the mantle
Carbon is one of the most important elements on planet Earth, not only was it essential for the emergence of life, but it plays a major role in many of the planet’s cycles. Although most of it lives in the planetary core, it is not yet clear whether carbon from the core can be transferred to the Earth’s mantle, because of the difficulty of studying this region.
But a recent study has found that such a transfer of the element into the mantle may indeed be occurring and that in the process, diamonds may be being released. “The formation of diamonds at the core-mantle boundary may have been occurring for billions of years since the onset of subduction on the planet,” explains lead author Dr. Byeongkwan Ko.
Diamonds in the Earth’s mantle
To hypothesize, Dr. Ko and his team recreated conditions in the Earth’s core. They compressed an alloy of iron, carbon, and water, simulating the pressure and temperature environment at the boundary between the Earth’s core and mantle. They found that the metal reacts with water to generate iron oxides and hydroxides, just like the oxidation on the surface of the planet.
However, they also observed that carbon comes out of the liquid alloy of iron and metal to form diamonds. Professor Dan Shim, the co-author of the study, explains that the temperature at the boundary between the silicate mantle and the metallic core, which is located at a depth of 3,000 kilometers, reaches 3,900°C. This temperature is high enough for most minerals to lose the water captured in their structures at scale. This temperature is high enough for most minerals to lose the water captured in their atomic-scale structures. It is so high that it is even enough for some minerals to melt.
Because the core is known to be composed of iron and because iron is a carbon-loving element, researchers believe that there is a significant amount of carbon in the core. Although this theory also stipulates that the mantle probably possesses a much smaller amount of the element.
However, in recent years geoscientists have discovered that there is much more carbon in the mantle than expected, leading to an even more interesting assumption. “The stable form of carbon under the pressure and temperature conditions of the boundary between the Earth’s core and mantle is diamond.”
Therefore, say the researchers, carbon escaping from the liquid outer core would be converted to diamond once it is transferred to the mantle. Only in this way could the previously unknown high amounts of carbon in the mantle be explained.
The study opens the door to a new understanding of the geophysical dynamics of the planet that is undoubted of great importance for understanding how the planet came to be configured as we know it today.
Story originally published in Spanish in Ecoosfera