A trove of water -in fact as much water as all the oceans on the planet’s surface combined -is hiding 400km beneath our feet.
Geoscientists had earlier thought that, below the transition zone where the Earth’s mantle meets the crust (at 410 km), a water- illed mineral called brucite was unstable and decomposed. As they decomposed, they released the water, which was recycled back to surface via volcanic activity. But this discovery of a new highpressure phase of brucite indicates that water could be efficiently transported to far deeper realms without decomposition.
According to a report in Times of India, a new research suggests that before brucite -which is 50% magnesium oxide and 50% water – ecomposes, it transforms into another, more stable 3D structure. The finding means there’s a stash of water located deeper in the Earth than was previously thought.
Unable to probe the deep Earth directly, the scientists used quantummechanical calculations, analysing various possible structures for brucite in deep-Earth conditions. After months of running various structures through their computer programme, the researchers found a previously unknown phase of brucite that would be able to withstand the high pressures found in the lower mantle.
Current estimates suggest that the deep Earth may hold as much water as all the oceans on the planet and this water is vitally important to the movement of materials through the Earth.