A recent study indicates that a massive hot rock blob located deep underground in New England, USA, is slowly moving towards New York.
This mysterious rock formation is known as the North Appalachian Anomaly (NAA) and is situated approximately 124 miles (200 kilometers) beneath the Appalachian Mountains in New England, spanning a width of 217 to 249 miles (350 to 400 kilometers). Positioned within the asthenosphere, a partially molten layer of Earth’s mantle, it is considered a thermal anomaly due to its higher temperature compared to its surroundings.
The lead author of the study, Tom Gernon, a professor of Earth Sciences at the University of Southampton in the UK, stated that this high-temperature rock blob has long puzzled geologists in North America.
The rock structures in this region of the Earth’s interior are abnormal. Scientists previously believed it formed 180 million years ago when North America separated from Northwest Africa. However, a new study published in Geology suggests that this hot rock blob emerged 80 million years ago, coinciding with the separation of Greenland and North America at that time.
Over time, this intensely hot and unstable rock blob deep beneath the surface has been slowly shifting towards its present location at a rate of about 20 kilometers per million years. According to the study, this rock formation is also moving in a southwesterly direction, expected to reach the underground areas of New York within the next 15 million years.
Gernon mentioned, “Although there is little evidence of ongoing plate tectonic activity at the surface, the effects of ancient rift systems continue to manifest deep in the crust. The impact of continental breakup on other parts of the Earth system may be broader and more long-lasting than previously recognized.”
Furthermore, simulation results suggest that this rock blob may contribute to the uplift of the Appalachian Mountains, explaining why the mountain range has maintained its significant height despite substantial erosion over the past 20 million years.
“The heat at the base of the continent weakens and removes some of its dense roots, making the continent lighter and more buoyant, like a hot air balloon ascending after releasing ballast. This has led to further uplift of ancient mountain ranges over the past million years,” Gernon explained, adding that once this rock blob moves away from the region, erosion will reduce the elevation of the Appalachian Mountains.
(Reference: Adapted from a report by CNN.)