[Rockhounds] Earthshaking Discovery: Tectonic Plates Not The Driving Force That Formed Continents

[Kreigh Tomaszewski]

Plate tectonics didn’t play the pivotal role in the formation of Earth’s
continents as once thought. A seminal discovery from geoscientists at the
University of British Columbia reveals that the continents actually
developed through internal geological processes within ancient oceanic
plateaus.

During the Archean Eon, which spanned from 2.5 to four billion years ago,
the Earth’s early crust
<https://studyfinds.org/ancient-diamonds-earth-evolution/> was primarily
formed from a unique combination of granitoid rocks known as tonalite,
trondhjemite, and granodiorite (TTG). These rocks have been central to
understanding the early continental formation
<https://studyfinds.org/how-did-earth-make-continents/>, but their origins
have remained elusive due to the complex geological processes they
underwent from initial melting to final crystallization.

“We tracked a specific set of trace elements that aren’t affected by
alteration and pristinely preserve signatures from the original magma
<https://studyfinds.org/earth-covered-ocean-magma/> that made new TTG
crust,” says study author Dr. Matthijs Smit, an associate professor and
Canada Research Chair at the University of British Columbia’s Department of
Earth, Ocean and Atmospheric Sciences, in a university release
<https://science.ubc.ca/news/researchers-uncover-source-rocks-first-real-continents>.
“These elements allowed us to look back through the chemical changes that
TTG magmas go through and trace the melt compositions back to their initial
state and source — most likely a sort of gabbro.”

Dr. Smit also notes this specific rock is found in many homes.

“Funnily enough, many people have varieties of this type of rock as a
kitchen countertop,” says Dr. Smit. “In a way, many people are preparing
their dinner on the type of rock that was responsible for making our modern
continents <https://studyfinds.org/milky-way-earth-planets/>.”

The significance of Archean TTG crust extends to the present day, as it
still constitutes a substantial part of continents. For example, in North
America, much of the Canadian Interior is composed of these ancient crustal
fragments.

https://studyfinds.org/plate-tectonics-earth-continents/