[Rockhounds] WAS EARTH ONCE A WATER WORLD?

[Kreigh Tomaszewski]

Was the Earth's surface once inundated with water?

Clever new research combining physical models with experiments adds to the
growing evidence that billions of years ago the Earth was a water world
<https://www.sciencemag.org/news/2021/03/ancient-earth-was-water-world>,
covered in twice as much water as it has on the surface now, possibly
submerging even the highest peaks.

It's not proof, but things really are starting to line up that this is the
case.

The mystery here lies in the Earth's mantle. This is the layer of extremely
hot (but not molten!
<https://blogs.scientificamerican.com/observations/the-floor-is-usually-not-lava/>)
rock under the relatively thin crust that extends down nearly 3,000
kilometers below the surface, and contains two-thirds of the Earth's mass.
The pressure and temperature of the mantle creates minerals not found on
the surface, like wadsleyite <https://en.wikipedia.org/wiki/Wadsleyite>,
ringwoodite <https://en.wikipedia.org/wiki/Ringwoodite>, and bridgmanite
<https://en.wikipedia.org/wiki/Silicate_perovskite>, which are forms of
olivine.

These minerals can store water in their structure, up to roughly 3% of
their weight. That may not sound like much, but remember the mantle holds
most of the Earth's mass. There's a *lot* of these minerals down there, and
they can hold a *lot* of water.

https://www.syfy.com/syfywire/was-earth-once-a-water-world