Deep beneath the North American continent, scientists have discovered a remarkable geological process where the roots of the continent are slowly eroding in blobs of rock. This phenomenon, known as “cratonic thinning,” is driven by the remnants of an ancient tectonic plate and provides a rare opportunity to observe this process in real time.
Lead researcher Junlin Hua from the University of Texas at Austin identified the observation, which was supported by his colleagues at the Jackson School of Geosciences. The team used seismic modeling techniques to visualize the dripping rock formations for the first time.
Cratons are ancient and stable rock formations that form the deep cores of continents, but they can still undergo changes over billions of years. In rare cases, these formations lose parts of their structure, particularly their deepest root layers. However, this thinning is different from previous observations in places like North China Craton, as it is happening now under the Midwestern United States.
Researchers stress that there is no immediate threat to the surface landscape. The dripping occurs in the Earth’s mantle at a glacial pace and is expected to taper off over time. The process is driven by mantle dynamics, which influence how tectonic plates evolve on a timescale of millions of years.
The study suggests that an ancient tectonic plate, the Farallon Plate, still plays an active role in reshaping the continent above it. The researchers used seismic data from the EarthScope project to build a high-resolution model that provided detailed insights into the Earth’s interior.
The discovery adds new layers to scientists’ understanding of how continents evolve over geological time and highlights the importance of studying deep processes shaping our planet.
Source: https://www.earth.com/news/north-american-continent-is-dripping-away-in-giant-blobs-of-rock-earth-mantle