Fluid processes in the early Earth and the growth of continents

Deep rock reservoirs of ancient water discovered

31 March 2023

The source of water needed to form the continents was buried much deeper in the early Earth than previously thought.

Water was required to transform ancient volcanic rocks into lighter ones that would float the Earth’s surface to form the continental crust. But where and how this water stored have long remained a mystery.

Now, a team led by a researcher from the University of Cape Town in South Africa has shown that primitive lavas with high magnesium contents would have soaked up and stored more seawater than modern lavas that have low magnesium contents.

Furthermore, the rocks would have released the water at a higher temperature of around 700 degrees Celsius, implying that they must have sunk deeper into the early Earth than previously thought.

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References

1. Earth and Planetary Science Letters 594, 117695 (2022). doi: 10.1016/j.epsl.2022.117695