The Great Lakes, a vital source of freshwater, owe their formation to an ancient geological phenomenon dating back 300 million years.
New research reveals that the Cape Verde hotspot, a plume of molten material rising from Earth's mantle, played a critical role in shaping the region long before glaciers carved out the lakes during the Ice Age.
Ancient Hotspot Under Great Lakes Revealed to Shape Their Formation
Like the hotspot that formed the Hawaiian Islands, the Cape Verde hotspot is an intense heat source beneath the Earth's crust. Currently active under the Cape Verde Islands in the Atlantic Ocean, it once lay beneath what is now North America.
The American Geophysical Union (AGU) noted that this hotspot caused the crust under the future Great Lakes to heat, stretch, and sink over tens of millions of years. These changes created depressions that glaciers later deepened and filled with water around 20,000 years ago.
Aibing Li, a seismologist at the University of Houston, and her team discovered the connection while studying seismic waves in the Great Lakes region. They observed variations in wave speeds depending on direction — a sign of crust deformation.
According to Live Science, Li and geologist Jonny Wu reconstructed how tectonic plates shifted over millions of years. Their findings showed the Cape Verde hotspot once lay beneath Lake Superior around 300 million years ago. It later migrated under Lakes Huron and Erie before moving offshore into the Atlantic about 170 million years ago.
Great Lakes' Formation Sparks Global Question About Lake Origins
The study sheds light on how hotspots, typically associated with volcanic activity, can shape landscapes without creating surface volcanoes.
The Great Meteor hotspot, another ancient plume, left a clearer trail of volcanic rocks in North America. However, evidence of the Cape Verde hotspot's influence was hidden beneath layers of crust.
This discovery also raises questions about other large lakes worldwide. Researchers are now exploring whether hotspots helped form these lakes by thinning the crust and creating low-lying areas.
Understanding the role of the Cape Verde hotspot offers new insights into Earth's geological history. From the volcanic origins of the Hawaiian Islands to the freshwater-filled Great Lakes, hotspots profoundly impact the planet's surface.
This research not only solves a long-standing mystery about the Great Lakes but also opens new avenues for studying how ancient geological forces continue shaping the world we live in today.
