Thursday, March 5, 2020

IN the NEWS - Archean Earth Was Covered by Global Ocean

And the waters prevailed exceedingly upon the earth;
and all the high hills, that were under the whole heaven,
were covered. Genesis 7:19

"The surface of Earth was likely covered by a global ocean (Archean Eon), according to a new study published in the journal Nature Geoscience.


In the study, Dr. Wing and colleagues examined hydrothermally altered oceanic crust from the Panorama district in the Pilbara Craton of Western Australia.

There are no samples of really ancient ocean water lying around, but we do have rocks that interacted with that seawater and remembered that interaction,” said Dr. Benjamin Johnson.

They were looking, in particular, for two different isotopes of oxygen trapped in stone: a slightly heavier atom called oxygen-18 and a lighter one called oxygen-16.
They discovered that the ratio of those two isotopes of oxygen may have been a bit off in seawater — with just a smidge more oxygen-18 atoms than you’d see today.
Though these mass differences seem small, they are super sensitive,” Dr. Wing said.

Sensitive, it turns out, to the presence of continents.
Today’s land masses are covered by clay-rich soils that disproportionately take up heavier oxygen isotopes from the water — like mineral vacuums for oxygen-18,” Dr. Wing said.
The study authors theorized that the most likely explanation for that excess oxygen-18 in the ancient oceans was that there simply weren’t any soil-rich continents around to suck the isotopes up.

Which leaves a big question: when did plate tectonics push up the chunks of rock that would eventually become the continents we know and love?
The scientists aren’t sure."
SciNews