Stash of Water May Be Lurking Deep Beneath Earth's Surface

Geoscientists had long thought that below this transition zone (starting at 255 miles, or 410 km, deep) a water-filled mineral called brucite was unstable and so decomposed, sending water molecules flowing toward the planet's surface. But new research suggests that before brucite — which is 50 percent magnesium oxide and 50 percent water — decomposes, it transforms into another, more stable 3D structure. The finding, detailed online Nov. 21 in the journal Proceedings of the National