New Delhi: A recent revelation by researchers of Northwestern University in Evanston, Illinois has sparked widespread attention on social media: the discovery of a massive ocean hidden beneath the Earth's crust. This immense body of water is stored 700 kilometres below the Earth's surface, settled within a mineral called ringwoodite.  

This subterranean reservoir dwarfs the combined volume of all the oceans on the planet, presenting a profound paradigm shift in our understanding of Earth's geology. These groundbreaking findings, explained in a 2014 scientific paper titled 'Dehydration melting at the top of the lower mantle', also shed light on the distinctive properties of ringwoodite.  

"At the time of the discovery," explained geophysicist Steve Jacobsen, a key member in the research team, "we likened ringwoodite to a sponge, capable of absorbing water. It's the unique crystal structure of ringwoodite that enables it to attract hydrogen and retain water."

"I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades," he added further. 

The scientists highlighted the significant water storage potential of minerals within Earth's mantle transition zone, spanning depths of 410 to 660 kilometres. This suggests the existence of a profound H2O reservoir capable of triggering dehydration melting in the downward flow of mantle material. Their investigation, employing a combination of high-pressure laboratory experiments, numerical modelling, and analysis of seismic P-to-S conversions, explored the implications of downward movement from the transition zone into the lower mantle.