[Rockhounds] Earth's crust is way, way older than we thought

[Kreigh Tomaszewski]

Like a fine French bread, *Earth*
<https://www.livescience.com/earth.html> would
be nothing without its crust. And like a fine French wine, that crust has
aged exceptionally well.

The rigid, rocky continental crust has been a feature of the planet for
billions of years (though only a small percentage of today's crust dates
back that far). How many billions of years, exactly, is hard to say. To
calculate the age of continents, researchers study the decay of ancient
chemicals trapped in rocks — typically, in carbonate minerals recovered
from the ocean. But those minerals are hard to find, and they are rarely in
pristine enough condition to analyze.

Now, a team of scientists has devised a new way to date ancient chunks of
crust — and according to their latest research, we've misjudged the age of
the continents by half a billion years.

In research presented April 26 at the virtual *European Geosciences Union
(EGU) General Assembly 2021*
<https://meetingorganizer.copernicus.org/EGU21/EGU21-4701.html> conference,
the team showed that by analyzing a mineral called barite — a combination
of ocean salts and *barium*
<https://www.livescience.com/37581-barium.html> released
by volcanic ocean vents — they found evidence that Earth's continental
crust was around at least 3.7 billion years ago, much older than previous
estimates.

That is a "huge" jump back in time, lead study author Desiree Roerdink, a
geochemist at University of Bergen, Norway, *said in a statement*
<https://www.egu.eu/news/843/new-research-uncovers-continental-crust-emerged-500-million-years-earlier-than-previously-thought/>.
"It has implications for the way that we think about how life evolved."

https://www.livescience.com/earth-continental-crust-older-than-we-thought.htm