A strange geological phenomenon—a massive ‘hot blob’ of molten rock—is slowly moving beneath the Appalachian Mountains toward New York City, according to a new study published in the journal Geology.
Researchers from the University of Southampton in the UK discovered the anomaly and confirmed it’s unlike anything they’ve seen before.
“This thermal upwelling has long been a puzzling feature of North American geology,” said Tom Gernon, lead author and Professor of Earth Science at Southampton.
What Is the ‘Hot Blob’?
Officially named the Northern Appalachian Anomaly (NAA), the hot blob is located about 125 miles underground and spans a massive 220-mile stretch beneath New England.
While earlier theories suggested it formed 180 million years ago during the split between North America and Africa, new evidence indicates it likely emerged just 80 million years ago, when the precursor landmasses of Canada and Greenland began to separate.
“It lies beneath part of the continent that’s been tectonically quiet for 180 million years, so the idea that it was just a leftover from when the landmass broke apart never quite stacked up,” Gernon explained.
What’s Causing It?
The research, also published in Nature, details how molten mantle material—sometimes described as “mantle molasses”—rises to fill gaps in the Earth’s crust caused by tectonic rifting. When the material cools and sinks, it creates a “mantle wave” effect that shifts layers of the Earth over time.
These waves are likely responsible for raising the Appalachian Mountains and keeping them elevated despite millions of years of erosion.
“Heat at the base of a continent can weaken and remove part of its dense root, making the continent lighter and more buoyant, like a hot air balloon rising after dropping its ballast,” Gernon added. “This would have caused the ancient mountains to be further uplifted over the past million years.”
Is the Hot Blob a Threat to New York?
Not immediately. The hot blob is moving at a pace of about 12 miles per million years, meaning it would take 10 to 15 million years to reach New York City.
Still, its presence is reshaping how scientists view the tectonic stability of North America and its long-term geological activity.
Could It Bring Diamonds to the Surface?
Interestingly, the researchers suggest that the hot blob could explain rare volcanic eruptions that bring diamonds from deep within the Earth to the surface—something not typically expected in regions considered tectonically quiet.
How Scientists Made the Discovery
Researchers combined:
- Geological field observations
- Plate tectonic modeling
- Computer simulations
This hybrid approach allowed scientists to virtually reconstruct how the blob formed and predict its future movement.
