A massive, slow-moving “hot blob” of rock located beneath the Appalachian Mountains is gradually making its way toward New York City, scientists revealed in a new study published in the journal Geology. The phenomenon, officially known as the Northern Appalachian Anomaly (NAA), lies about 125 miles beneath the mountains and stretches approximately 220 miles across the New England region. According to researchers, the NAA is drifting southwestward at a rate of nearly 12 miles per million years. At this pace, the geological structure is expected to reach the vicinity of New York in roughly 10 to 15 million years. “This thermal upwelling has long been a puzzling feature of North American geology,” said Tom Gernon, the study’s lead author and Professor of Earth Science at the University of Southampton. The study suggests that the anomaly likely formed around 80 million years ago during the separation of Greenland and North America. This finding revises the earlier theory which linked the formation to the breakup of North America and Africa nearly 180 million years ago. “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,” Gernon said. Scientists believe that heat from the blob has played a role in elevating the Appalachian Mountains, helping them retain height despite extensive erosion over time. The crust beneath the mountains is expected to gradually settle, leading to a possible reduction in elevation in the distant future. “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. This would have caused the ancient mountains to be further uplifted over the past few million years,” Gernon explained. Sascha Brune of the GFZ Helmholtz Centre for Geosciences in Germany noted that these types of geological features may not be isolated. “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,” Brune said. “The feature we see beneath New England is very likely one of these drips, which originated far from where it now sits.” The study relied on a combination of geological observations, plate tectonic models, geodynamic theory, and advanced computer simulations to examine the behaviour and origin of the NAA. Researchers said the findings could provide new insights into the deep processes shaping Earth’s geology and highlight the long-lasting impact of ancient continental shifts.
