The theory of continental drift was proposed by German meteorologist Alfred Wegener more than a century ago in 1912. According to the theory, the continents we know today were once connected as one big “supercontinent” called Pangea. The theory explains why continental coasts align like puzzle pieces, and why fossils from certain species are found in vastly different places.
But the deep-Earth story beneath North America is stranger than a simple breakup map. In a 2025 study published in the journal Geology, a team of international scientists argued that a giant, Northern Appalachian Anomaly (NAA)—a giant, unusually hot blob in the upper mantle beneath New England—may not be left over from the much older opening of the Central Atlantic. Instead, the team traced it to Labrador Sea rifting, when Greenland and North America began pulling apart roughly 80 million years ago.
And eventually, it’s heading toward New York.
“This thermal upwelling has long been a puzzling feature of North American geology,” lead author of the study Tom Gernon said in a press release. “Our research suggests it’s part of a much larger, slow-moving process deep underground that could potentially help explain why mountain ranges like the Appalachians are still standing.”
Experts estimate the NAA is around 350 kilometers (218 miles) wide, and it currently sits 200 kilometers (124 miles) beneath the Appalachian Mountains in New England. Scientists see it indirectly in seismic data: earthquake waves slow down as they pass through it, a signal that’s usually linked with hotter or weirdly shaped mantle rock.
Using geodynamic simulations, tectonic plate reconstructions, and seismic tomography data, researchers traced the origins of the mass back to the Labrador Sea, where Canada and Greenland began splitting around 80 million years ago. Researchers estimate that the blob migrates at a rate of 20 kilometers (12 miles) per million years. Per the team’s calculations, the mass is steadily heading toward New York City, and its center should pass beneath the region in about 15 million years.
The study expands on recent research that proposed a new idea called the “mantle wave” theory, which posits that the molten material beneath Earth’s surface behaves almost like a lava lamp. When continents divide, hot, dense rock bubbles off the base of tectonic plates, and the “waves” move across continents’ lower surfaces. Once beneath the base of a continent, the heat from the blob works like the fire in a hot air balloon, making the continent more buoyant. Researchers believe this phenomenon could’ve caused ancient mountains to be “further uplifted” over the past few million years.
“Our earlier research shows that these ‘drips’ of rock can form in series, like domino stones when they fall one after the other, and sequentially migrate over time,” co-author Sascha Brune said in the press release. “The feature we see beneath New England is very likely one of these drips, which originated far from where it now sits.”
There have been a few new developments since the study published last year. At a March 2026 Geological Society of America Northeastern Section meeting, Yale scientists reported preliminary seismic evidence consistent with vertical mantle flow near the center of the NAA.
Needless to say, this is certainly an example of “slow and steady wins the race”—at least when it comes to forming the continents. According to Gernon, there is still a lot to learn about how the continents came to be arranged in the way we see them today.
“Even though the surface shows little sign of ongoing tectonics, deep below, the consequences of ancient rifting are still playing out,” he explained in the release. “The legacy of continental breakup on other parts of the Earth system may well be far more pervasive and long-lived than we previously realised.”
