How the Earth’s Mantle Sends Water Up Toward the Surface
Hidden inside the Earth—within the first several hundred kilometers below the crust—there is another ocean. It is, most likely, the largest ocean in the world. This water is not sloshing around in a big pool. No fish plumb its depths. In fact, this ocean is only water in the loosest sense: broken into its composite hydrogen and oxygen atoms and chemically bound to the surrounding rock, this ocean is in storage.