A new study by researchers at the University of Southampton has found that a region of unusually hot rock deep beneath the Appalachian Mountains in the United States is linked to Greenland and North America splitting apart 80 million years ago. The scientists argue against the long-held theory that the continent broke away from Northwest Africa due to plate tectonic movements.
The Northern Appalachian Anomaly (NAA) is a 350-kilometre-wide region of anomalous hot rock, approximately 200 km beneath the Appalachian Mountains in New England. According to the research, this area developed about 1,800 km from where it is now, when the Earth’s crust began to break apart near the Labrador Sea between Canada and Greenland.
The study suggests that over time, this area of hot, unstable rock has slowly moved to its current location at a rate of approximately 20 km per million years. The research team proposes the “mantle wave” theory, which describes how hot, dense rock peels away from the base of tectonic plates after continents break apart.
According to Professor Tom Gernon, lead author of the study, this process can weaken and remove part of a continent’s dense root, making it lighter and more buoyant. This would cause ancient mountains like the Appalachians to be further uplifted over the past few million years. The team’s findings have significant implications for understanding the dynamics of continental ice sheets from below.
The research also proposes that a similar anomalous hot zone beneath north-central Greenland may share the same origin, making it an effective mirror image twin of the NAA. This discovery highlights the ongoing role of deep Earth processes in shaping the Earth system, even after surface plate boundaries have ceased to be active.
Source: https://www.eurekalert.org/news-releases/1092740