Researchers are surprised to learn that there may be water deeper within the Earth than previously thought. Two scientists from The University of Edinburgh and Florida State University (FSU) discovered a high-pressure phase of a mineral that may be able to store water 400 to 600 kilometers, or almost 250 miles to 372 miles, down in Earth’s mantle. Researcher Mainak Mookherjee said the find “opens up a Pandora’s Box for us.”
The mineral, brucite, was not thought to be stable so far down in the Earth. But the discovery of what FSU describes as a high-pressure polymorph of brucite has exciting implications for our knowledge of Earth’s interior. Mookherjee said, “We didn’t think water could be stored by hydrous minerals such as brucite. But now that we know it’s there, we need to figure out how much water could be effectively stored inside it…It really is remarkable that such a well-studied mineral as brucite has something so surprising to offer.”
Scientists used to think brucite would decompose in deep Earth, and volcanic activity would send the water it once held up to the planet’s surface. But a high-pressure phase of the mineral might not decompose, so brucite may be able to hold water deep down there after all. Mookherjee said what he describes as deep Earth water is just as important as water on Earth’s surface for the planet’s processes. He said, “If the planet becomes dry on the inside, the planet dies because geodynamic activity within the planet ceases.”
The scientists will continue to research brucite and will conduct more simulations to determine how its physical properties differ so deep in the Earth. Mookherjee’s ultimate goal is to figure out just how much deep Earth water there is. The journal Proceedings of the National Academy of Sciences recently published the study online.