GUANGZHOU, Dec. 12 — Chinese scientists have uncovered a crucial mechanism explaining how Earth may have stored vast quantities of water in its infancy, shedding new light on the planet’s dramatic evolution from a fiery ball of magma to the life-nurturing world of today.
Researchers from the Guangzhou Institute of Geochemistry under the Chinese Academy of Sciences have experimentally demonstrated that the planet’s deep mantle could have acted as a massive reservoir for water over four billion years ago, according to the study published on Friday in the journal Science.
“Where did the water go when Earth’s early magma oceans crystallized? For the deepest mantle, the answer has been elusive,” the journal stated in an editorial summary.
The key lies in bridgmanite, the dominant mineral in the lower mantle.
While previously thought to have limited water storage capacity, the Chinese team has discovered that the mineral actually exhibits a powerful, temperature-dependent ability to trap water.
They recreated the extreme conditions of the lower mantle — high pressure and scorching temperatures up to approximately 4,100 degrees Celsius — using a sophisticated diamond anvil cell apparatus combined with laser heating.
Their findings reveal a paradox: the hotter the environment, the more efficiently bridgmanite captures and stores water molecules during its formation from cooling magma.
This process could have locked away in the solid mantle an amount of water equivalent to between 0.08 and 1 times the volume of all modern oceans, according to the study.
This primordial “water stockpile” has been gradually cycled back to the surface through volcanic activities, contributing to the formation of a blue, habitable planet. (Namibia Daily News/Xinhua)
