New research suggests that the formation of the Great Lakes is linked to a hotspot that was active hundreds of millions of years ago. The Cape Verde hotspot, currently located beneath an island nation in the Central Atlantic Ocean, once sat under what would become North America during the supercontinent Pangaea. This ancient hotspot heated and stretched the Earth’s crust, creating a low-lying topography. When glaciers arrived around 20,000 years ago, they scraped out this region and left behind depressions that filled with meltwater as they retreated.
The Great Lakes hold about 20% of the world’s fresh water and were formed through a combination of geological and glacial processes spanning hundreds of millions of years. The Cape Verde hotspot caused the lithosphere to thin and create a low-lying area, which was later shaped by glaciers during the last ice age. The stability of the North American continent allowed the hotspot to shape the region’s topography without producing volcanic activity.
According to researchers, the presence of positive radial-anisotropy anomalies in the eastern Great Lakes, central Pennsylvania, and northwestern Virginia aligns with the Cape Verde hotspot track. This discovery links ancient mantle activity to the present-day geography of the Great Lakes, highlighting how Earth’s internal processes can shape features that have a profound impact on ecosystems and human life.
The study also notes that the maximum area covered by ice on the Great Lakes has declined significantly since 1973 due to climate change, with long-term trends showing a decline in Lake Superior. The research was published in the journal Geophysical Research Letters.
Source: https://www.newsweek.com/how-did-great-lakes-form-scientists-reveal-hidden-secret-2011485