[Rockhounds] North America is dripping from below, geoscientists discover

[Kreigh Tomaszewski]

Researchers have discovered that the underside of the North American
continent is dripping away in blobs of rock—and that the remnants of a
tectonic plate sinking in Earth's mantle may be the reason why.

A paper published in *Nature Geoscience*
<https://www.nature.com/articles/s41561-025-01671-x> describes the
phenomenon, which was discovered at The University of Texas at Austin. It's
the first time that "cratonic thinning" may be captured in action.

"We made the observation that there could be something beneath the craton
<https://phys.org/tags/craton/>," said the study's lead author Junlin Hua,
who conducted the research during a postdoctoral fellowship at UT's Jackson
School of Geosciences. "Luckily, we also got the new idea about what drives
this thinning."

Cratons are very old rocks that are part of Earth's continents. They're
known for their stability and ability to persist for billions of years. But
sometimes cratons undergo changes that can affect their stability or that
remove entire rock layers.

For example, the North China Craton lost its deepest root layer millions of
years ago.

What makes the discovery of cratonic dripping special, said the
researchers, is that it's happening right now. This allows scientists to
observe the cratonic thinning process as it occurs.

https://phys.org/news/2025-04-north-america-geoscientists.html