University of Houston study suggests ancient hotspot shaped Great Lakes

A new study from the University of Houston challenges previous beliefs about the formation of North America's Great Lakes. Aibing Li, a seismologist and co-author of the study, suggests that the Cape Verde hotspot played a significant role in their creation.

Li stated, "We saw something strange in this area. Before, people thought the Great Lakes were formed during the ice age. Our study shows it started from the deep mantle." The research indicates that this process began hundreds of millions of years ago, before Pangaea's separation. As North America moved above the Cape Verde hotspot, it traveled through what is now the Great Lakes region.

Li explained that hotspots are plumes of hot material rising from Earth's mantle and can create volcanoes when interacting with Earth's surface. However, detecting ancient hotspots within continents is challenging. "When the hotspot was in the continent, it behaved differently from when they were in the ocean," Li said.

The team used a seismic velocity anisotropy model to identify an anomaly under northeastern America's crust where earthquake waves traveled at different velocities horizontally and vertically. Initially skeptical about a hotspot's involvement, further analysis revealed that plate movement positioned the Cape Verde hotspot beneath today's Great Lakes for 300 million to 200 million years ago.

"My colleague showed me a video of hotspots and plate movement," Li noted. "We saw the Cape Verde hotspot was right where the Great Lakes were for a pretty long time."

This discovery offers new insights into what shaped not only the Great Lakes but potentially other lakes or land masses around North America as well. Li expressed hope that this will stimulate further research on lake formation processes: "This is a new idea, a change of notion that lakes are formed more recently due to processes near the surface."

Li plans to expand her research westward across more parts of North America's inland lakes while investigating general dynamics between hotspots and continents with varying lithosphere characteristics such as those found throughout different regions within United States territories.

"When lithosphere is very different," she said regarding these variations across U.S., "we want know if a hotspot will produce different or similar features at depths on surface."