GUANGZHOU, Dec. 12 (Xinhua) — Chinese researchers have uncovered a key mechanism that may explain how Earth stored vast amounts of water in its earliest days, offering new insights into how the planet evolved from a molten mass to the life-supporting world we know today.
A team from the Guangzhou Institute of Geochemistry, under the Chinese Academy of Sciences, has shown through experiments that Earth’s deep mantle could have served as a colossal water reservoir more than four billion years ago, according to a study published Friday in the journal Science.”Where did the water go when Earth’s early magma oceans crystallized? For the deepest mantle, the answer has remained a mystery,” the journal noted.
The breakthrough centers on bridgmanite, the most abundant mineral in the lower mantle. Once thought to have only limited capacity to store water, the Chinese scientists discovered that its ability to trap water is much stronger and depends on temperature. Using a diamond anvil cell with laser heating, the researchers simulated the extreme conditions of the lower mantle — pressures and temperatures reaching around 4,100 degrees Celsius.
Their results revealed a surprising trend: the hotter the environment, the more efficiently bridgmanite can capture and retain water molecules as magma cools and solidifies. According to the study, this process could have stored an amount of water in the deep mantle equivalent to between 0.08 and 1 times the volume of all the oceans on Earth today. Over billions of years, this primordial “water stockpile” has gradually resurfaced through volcanic activity, helping to create the planet’s oceans and making Earth a blue, habitable world.
