Massive Underground Ocean Exists Beneath Earth's Crust

Summary: The first terrestrial discovery of Ringwoodite confirms the presence of massive amounts of water 400 to 700 kilometers beneath Earth's surface. Ringwoodite is a form of the mineral peridot, believed to exist in large quantities under high pressures in the transition zone. Ringwoodite has been found in meteorites but, until now, no terrestrial sample has ever been unearthed because scientists haven't been able to conduct fieldwork at extreme depths.

Scientists scanning the deep interior of Earth have found evidence of a vast water reservoir beneath eastern Asia that is at least the volume of the Arctic Ocean.

The discovery marks the first time such a large body of water has found in the planet's deep mantle. [The World's Biggest Oceans and Seas]

Water covers 70 percent of Earth's surface and one of its many functions is to act like a lubricant for the movement of continental plates.

The crust thickness averages about 18 miles (30 kilometers) under the continents, but is only about 3 miles (5 kilometers) under the oceans. It is light and brittle and can break. In fact it's fractured into more than a dozen major plates and several minor ones. It is where most earthquakes originate. The Earth’s radius is about 4,000 miles (6,400 kilometers). The main layers of its interior are in descending order: crust, mantle and core. The mantle is more flexible – it flows instead of fractures. It extends down to about 1,800 miles (2,900 kilometers) below the surface. The core consists of a solid inner core and a fluid outer core. The fluid contains iron, which, as it moves, generates the Earth’s magnetic field. The crust and upper mantle form the lithosphere, which is broken up into several plates that float on top of the hot molten mantle below. SOURCE: LiveScience