North America is sinking: Some parts are being pulled into the Earth's mantle, says study

For years, scientists believed continents split millions of years ago. The Atlantic Ocean was thought to separate North America and Europe. (Image: Canva)

Under the American heartland, something unusual is quietly occurring. Scientists have found that parts of North America's surface are being pulled deeply into the Earth by ancient crust that lies buried under the Midwest.

The continent's foundations could be moving as a consequence of this massive underground movement.

Unidentified Drops Under the Surface

Gigantic "rock drips" under the continent are indicated by the research, published on March 28 in the journal Nature Geoscience. Stretching from Michigan to Nebraska and perhaps Alabama, these regions of buried crust are found. Some lie as far underground as 640 kilometers.

The researchers had evidence that an object was pulling the crust downward, said primary author Junlin Hua. He explained, "We found that there may be something under the craton."

A leftover slab from the ancient Farallon tectonic plate is "something." Nearly 20 million years ago, the plate cracked apart after sliding under North America. Rock is still being pulled into the mantle by one gigantic slab that is still under the Midwest.

For The First Time, Craton Thinning Is Seen

This push downwards is creating a process referred to as cratonic thinning. Existing for billions of years, with a lifespan as long as their existence, cratons are the most stable and oldest structures of the Earth's crust.

Cratonic thinning has never before been seen in action by scientists until this day.
Hua noted, "A very broad range is experiencing some thinning." The team believes this untypical geologic action is created by the Farallon slab.

Scientists used full-waveform inversion, an advanced method of interpreting seismic waves, to reach their conclusion. Consequently, they were able to generate high-resolution images of the Earth's interior that illustrated the funneling of crust into the mantle.

Mysterious Rock Movement Verified by Simulations

Their hypothesis was confirmed by computer models. The anomalous drips of the odd rocks appeared when the Farallon slab was added to the models. They vanished when it was removed.
As a University of Texas at Austin geophysicist and co-author, Thorsten Becker said, "This type of thing matters if we're going to know how a planet has evolved over millions of years."

Scientists indicated there is nothing to worry about even with the stunning discovery. Surface life will not be affected by the extremely slow process anytime in the near future. As the slab goes deeper into the earth, it may possibly stop moving.

Becker added, "This helps us understand how you make continents, break them, and recycle them."

The Jackson School of Geosciences at UT Austin and the National Science Foundation provided funding for the project. Participants included scientists from Chinese institutions, the University of Nevada, and the University of Hawai‘i.