Craters or sinkholes? Scientists investigate mysterious formations beneath lake Michigan

Scientists made a remarkable discovery beneath the surface of Lake Michigan using sonar technology .

As per LiveScience, strange circles were detected at the lakebed, and new research is now providing insights into these intriguing formations.

The mysterious shapes were initially found during a mission to map the lakebed within the Wisconsin Shipwreck Coast National Marine Sanctuary, an area known for its numerous shipwrecks. Maritime archaeologist and sanctuary superintendent Russ Green described the discovery as particularly exciting, saying, "Any kind of new discovery in the Great Lakes is exciting, but these features really stand out."

It wasn't until a joint survey in August 2024 that researchers, including Green and his colleagues from NOAA 's Great Lakes Environmental Research Laboratory (GLERL), confirmed the shapes to be enormous craters at the lakebed. Using a remotely operated vehicle, they surveyed the site southeast of Sheboygan, Wisconsin, and discovered approximately 40 craters, with diameters ranging from 500 to 1,000 feet.

Local shipwreck hunter Brendon Baillod had also noticed these formations while searching for a sunken freighter. He described the depressions as irregularly shaped craters, some between 20 to 40 feet deep, and suggested that trapped gas or water upwelling might be responsible for their formation rather than sinkholes .

Kevin Cullen, the Director of the Wisconsin Maritime Museum , expressed his curiosity about the craters, highlighting the geological mystery . With only a small portion of Lake Michigan's floor explored, Cullen proposed that the formations could be connected to underwater gorges created by glaciers centuries ago.

Geologists have noted that the craters could be sinkholes, as Lake Michigan partially sits on limestone, a rock type susceptible to dissolution and cavity formation. However, recent surveys found no water escaping from the holes, which would indicate groundwater movement. Experts like Steve Ruberg from GLERL believe it's only a matter of time before they detect signs of water circulation beneath the lakebed.

During the survey, images and videos captured life thriving in the deep craters, including freshwater shrimp, small fish, and invasive quagga mussels. Researchers are now focused on understanding the role these craters play in Lake Michigan's ecosystem and how they might impact the lake as a whole.

While much has been uncovered about these formations, many questions remain unanswered. Researchers like Russ Green are excited about what future investigations will reveal, stating, "We'll be exploring them for years to come to learn more, and sort out how they got there and what role they play in Lake Michigan's ecosystem." For now, the massive craters remain one of the Great Lakes' most intriguing geological mysteries, with more secrets likely to emerge as further research continues.