Scientists reported that nearly 80 million years ago, a large pile of hot rocks buried deep in the Appalachian Mountains might have attributed to ancient African tectonics.
The heat upwelling, known as the Northern Appalachian Anomaly (NAA), appears to be a slow legacy of the rift event, is now far from its birthplace below the northeastern United States.
This new perspective reshapes long-term assumptions about one of North America’s most confusing geological features. The anomaly lies beneath a constructed quiet area, and its heat and depth have not been easily explained – so far.
Slow motion journey from the Labrador Sea
According to researchers at the University of Southampton, the GFZ Helmholtz Centre in Germany and the University of Florence, the NAA may have started to form when Greenland began drifting from Canada, creating the Labrador Sea. At that time, the heat-unstable rock began to peel off from the bottom of the Earth’s lithosphere.
Over millions of years, this instability (a “drip” of hot rock) migrated southwest to the continental slab, covering nearly 1,800 kilometers. It moves at a speed of about 20 kilometers per million years and is now located 200 kilometers below the Appalachian Mountains.
“This heat upwelling has been a confusing feature of North American geology,” said Tom Gernon, lead author of geosciences and professor of geosciences at the University of Southampton. “It is located in part of the continent, and in the 180 million years of tectonic construction, it’s just a leftover, and when it breaks from land, it’s just a leftover that never completely piles up.”
Mantle wave theory
To explain this geological movement, the team turned to a new idea they recently proposed: the mantle wave theory. The concept likens the Earth’s deep mantle to a lava lamp where dense rock spots peeled off and rotated under the tectonic plate for tens of millions of years.
“The heat at the bottom of the continent can weaken and remove part of its dense roots, making the continent lighter and more buoyant,” Gerton explained. “Like a hot air balloon rises after putting down the ballast, this will lead to further uplifting of the ancient mountains over the past few million years.”
Scientists use geodynamic simulations and seismic tomography (essentially Earth images of Earth’s waves) to trace the path of NAA to the Labrador Sea Fracturing region, which originated from 900 to 80 million years ago.
Major findings from the study
– Northern Appalachian anomalies may have originated 1,800 km northeast of the Labrador Sea
– It immigrates at a range of about 20 kilometers per million years and now lives in New England
– The thermal area is about 350 kilometers wide and is 200 kilometers below the surface
– Mirror exceptions below Greenland may have the same crack origin
– Today’s dire fire is still raising the Appalachian mountains today
Twin abnormalities in Greenland
Similar areas in the hot rocky area beneath the green area in the north-central region may be the long-lost twins of NAA. Researchers believe it also comes from the Labrador Sea breakup, but on the opposite side.
This thermal anomaly may affect the Greenland ice sheet from below, thereby changing the way it moves and melts. As Gernon puts it, “The ancient thermal anomalies continue to play a key role in shaping the dynamics of the continental ice sheet from below.”
Rethinking the stability of the continent
Dr. Derek Keir, co-author of the University of Southampton and the University of Florence, emphasized the broader meaning: “The cracks on the continent cause dripping of the continent and the depth of the elements of the circulating hot rock, which gives us a look at the continents today and on Earth for thousands of kilometers of inland.”
The seemingly stable land may still be shaped by ancient divisions deep in the surface.
Even if the Appalachian region does not show active tectonic activity today, the lingering heat of the ancient cracks may quietly affect its terrain. According to Gernon, “The legacy of continental decomposition in other parts of the Earth’s system may be more universal and longevity than we have previously realized.”
refer to
Magazine: geology
doi: 10.1130/g53588.1
Article title: Feasible Labrador Ocean Fracture Area Origins in Northern Appalachia and Related Earthquake Anomalies
Author: Thomas M. Gernon, Sascha Brune, Thea K. Hincks, Derek Keir
Publication date: July 30, 2025
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