Far beneath the Earth’s surface, at depths unreachable by any drill, exists a mysterious mineral called ringwoodite. Though invisible to the human eye and buried within the Earth’s mantle, this mineral could help answer one of the most profound questions in geology: Where is Earth’s missing water?
Ringwoodite has stunned scientists because of its unique ability to trap water molecules inside its crystal structure. The presence of ringwoodite deep within the planet suggests there may be vast underground water reservoirs, possibly larger than all of Earth’s surface oceans combined.
What Is Ringwoodite?
Ringwoodite is a high-pressure form of the mineral olivine, created under intense heat and pressure at depths between 410 and 660 kilometers below Earth’s surface—in a region known as the transition zone of the mantle.
Unlike regular rock, ringwoodite can hold significant amounts of hydrogen and hydroxide ions in its crystal lattice, effectively locking in water not as a liquid, but as a part of its structure.
The mineral was named after Australian geophysicist Ted Ringwood, who studied the behavior of minerals under extreme pressure. It was first discovered in meteorites and later found in tiny diamond inclusions from deep within the Earth.
The 2014 Breakthrough Discovery
In 2014, researchers at Northwestern University and the University of Alberta made headlines when they reported the discovery of ringwoodite inside a diamond from Brazil. This inclusion proved for the first time that water exists deep in Earth’s mantle.
According to the study led by Graham Pearson, the sample contained about 1.5% water by weight, trapped in the mineral. If the mantle’s transition zone is filled with similar ringwoodite, the total water storage could rival or exceed the amount of water in all oceans combined.
Reference: Pearson, G. D., et al. (2014). “Hydrous Ringwoodite Inclusion in a Diamond Confirms a Deep Mantle Water Reservoir.” Nature.
Why Is This Important?
- Hidden Water Cycle: It supports the theory that Earth has a deep water cycle, where water moves not only on the surface but also through the mantle.
- Volcanic Activity: Water in the mantle affects how magma forms and erupts, influencing volcanism around the globe.
- Planetary Science: Understanding ringwoodite helps us model other rocky planets and moons. If Earth hides water deep inside, maybe others do too.
This discovery doesn’t mean there’s a literal underground ocean. Rather, the water is locked in minerals, but its volume is enormous.
How Do Scientists Study Ringwoodite?
Because it forms deep below the surface, ringwoodite cannot be collected directly. Scientists study it through:
- Seismic wave analysis – observing how earthquake waves travel through different mantle layers.
- High-pressure lab experiments – simulating the conditions of the mantle to create ringwoodite in the lab.
- Diamond inclusions – analyzing natural diamonds that contain trapped mantle minerals.
These methods allow researchers to uncover the mysteries of Earth’s deep interior without digging.
Glossary
- Ringwoodite – A high-pressure form of olivine that contains water in its structure.
- Mantle – The layer of the Earth beneath the crust and above the core.
- Transition zone – A section of the mantle between 410–660 km depth.
- Inclusion – A mineral or substance trapped inside another mineral (like a diamond).
- Hydrous – Containing water or moisture.
