Researchers at Northwestern University have announced the discovery of a vast water reservoir located about 700 kilometers beneath the Earth’s surface, deep within the mantle. This hidden reservoir is estimated to be three times larger than all the Earth’s surface oceans combined.
Using a network of 2,000 seismographs deployed across the US, scientists analyzed seismic waves from over 500 earthquakes. They observed a slowdown in wave velocity in a specific area of the mantle, indicating the presence of a substance acting as a sponge for the rocks leading them to conclude that water exists in that region.
This water is contained within a mineral called ringwoodite, which can store significant amounts of water molecules within its crystal structure. This discovery supports the theory that Earth’s oceans may have originated from water seeping from within the planet, rather than solely from cometary impacts. It also helps explain the stability of surface ocean sizes over millions of years, highlighting a complex interaction between Earth’s interior and its surface.
While this reservoir is not an ocean in the conventional sense, the water plays a crucial role in regulating the Earth’s surface oceans. Researchers suggest that without this hidden water, our planet would primarily consist of mountains, with minimal visible land.
The research team plans to expand their seismic studies globally to determine whether the melting of the mantle is a widespread phenomenon or localized to specific areas. Understanding this hidden water reservoir could shed light on its impact on geological activities, including earthquakes and volcanic eruptions, thus enhancing our knowledge of Earth’s inner workings and the intricate water cycle.