A significant geological discovery reveals that a large mass of hot rock, known as the Northern Appalachian Anomaly (NAA), is moving slowly beneath the Appalachian Mountains in the northeastern United States. This anomaly is now believed to be linked to the geological separation of Greenland and Canada approximately 80 million years ago, according to a study conducted by an international team of researchers. The findings challenge the long-held belief that the breakup of the North American and African continents, which occurred around 180 million years ago, was responsible for this phenomenon.
To support their hypothesis, the researchers utilized a combination of existing geological data and advanced computer modeling. They established a connection between the NAA and a geological formation in the Labrador Sea, dated to around 85-80 million years ago. This revelation offers a new perspective on the processes that have shaped North American geology.
Thomas Gernon, an earth scientist at the University of Southampton in the UK, emphasized the significance of this thermal upwelling, stating, “This thermal upwelling has long been a puzzling feature of North American geology. It lies beneath part of the continent that’s been tectonically quiet for 180 million years, so the idea it was just a leftover from when the landmass broke apart never quite stacked up.”
The NAA spans approximately 350 kilometers (about 217 miles) in width and has been moving at a rate of around 20 kilometers every million years. At this pace, the blob is expected to reach New York in approximately 10 to 15 million years. Researchers believe that this anomaly plays a crucial role in maintaining the Appalachian Mountains’ elevation, as the heat generated helps keep the continental crust buoyant.
Linking Geological Events
The recent study builds upon previous research from some of the same scientists, who proposed the ‘mantle wave’ theory. This theory posits that blobs of hot rock rise in a manner reminiscent of a lava lamp when continents break apart, leading to various geological phenomena, such as volcanic eruptions and mountain formation.
Sascha Brune, a geophysicist at the GFZ Helmholtz Centre for Geosciences in Germany, explained, “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. The feature we see beneath New England is very likely one of these drips, which originated far from where it now sits.”
The research team indicated that further analysis and tracking of the hot rock will be essential in confirming its origins. They also noted that the same theories and techniques could be applied to identify other geological features similar to the NAA. In fact, the researchers believe they may have already identified a ‘mirror’ anomaly beneath north-central Greenland, which also traces its origins back to the Labrador Sea.
Derek Keir, a geophysicist from the University of Southampton, remarked, “The idea that rifting of continents can cause drips and cells of circulating hot rock at depth that spread thousands of kilometers inland makes us rethink what we know about the edges of continents both today and in Earth’s deep past.”
The findings from this study have been published in the journal Geology, marking a significant advancement in the understanding of geological processes related to continental dynamics and their long-term effects on land formations.
