Scientists have recently found a huge water reservoir buried deep under Earth’s surface, held within a mineral called ringwoodite. This hidden “ocean” is believed to be three times larger than all the surface oceans combined, lying about 700 kilometers down in the mantle.
This discovery challenges the long-held belief that Earth’s water mostly came from comets. According to Steven Jacobsen, a geophysicist at Northwestern University, there’s a strong possibility that water seeped from the Earth’s interior over millions of years. Jacobsen notes this could dramatically change our understanding of Earth’s history.
“These mineral transformations greatly hinder the movements of rock in the mantle,” said Professor Frank Brenker from Goethe University in Frankfurt.
This massive water reservoir might explain why Earth’s oceans have been fairly stable in size for such a long time. Jacobsen suggests that it could act like a natural buffer, helping regulate ocean volumes and preventing sudden changes in sea levels. He emphasizes, “It’s strong evidence that Earth’s water came from within.” This raises an important question: how much water remains trapped deep in the planet?
To locate this underground reservoir, Jacobsen’s team set up over 2,000 seismometers. They studied seismic waves from more than 500 earthquakes, finding that these waves slowed down when they encountered water-laden rocks like ringwoodite. This slowdown confirmed the presence of water deep inside the mantle. They further enhanced their findings by recreating extreme conditions found 700 kilometers below the surface. Their experiments echoed earlier work by Graham Pearson, who discovered water in another ringwoodite crystal extracted from volcanic material.
“Since our initial report of hydrous ringwoodite, we’ve found another ringwoodite crystal, also containing water, so the evidence is now very strong,” Pearson stated.
Water in ringwoodite could play a significant role in regulating heat and material movement between the mantle and Earth’s surface, potentially influencing tectonic activity. While researchers have confirmed this reservoir beneath the United States, they aim to explore its existence globally.
“We should be grateful for this deep reservoir,” Jacobsen remarked. “If it wasn’t there, it would be on the surface of the Earth, and mountain tops would be the only land poking out.”
This new insight offers a fresh perspective on Earth’s inner dynamics and may reshape our understanding of how it formed and how water circulates within it. As scientists continue to study these hidden depths, we may uncover even more about our planet’s secrets.
