Earth's mantle may hold massive water reservoirs within minerals

Scientific research has identified the potential for massive water reservoirs located deep within the Earth's mantle. Rather than existing as liquid oceans, this water is chemically integrated into the molecular structure of minerals under extreme pressure and temperature.

Studies published in Nature Geoscience suggest that new iron oxyhydroxides, specifically Fe5O12Hx and Fe7O12Hx, can form in the lower mantle at depths of nearly 3,000 kilometers. These compounds are capable of storing hydrogen even in environments with very low water availability.

Additionally, in the transition zone between 410 and 660 kilometers deep, minerals such as ringwoodite and wadsleyite act like 'mineral sponges.' These high-pressure forms of olivine can incorporate significant amounts of hydrogen and oxygen into their crystal structures. If even 1% of the weight of the rocks in this transition zone consists of water, the total volume could be equivalent to nearly three times the volume of all surface oceans.