In 2024, Joël Lapointe was doing what a lot of campers do before a trip into Quebec's remote Côte-Nord region: scanning satellite maps for a good spot near Lake Marsal. What he noticed instead was a nearly perfect circle etched into the landscape, unlike anything a river or glacier typically carves. Lapointe, an amateur astronomer, flagged it to researchers rather than let it go, and that tip eventually led scientists to one of the largest impact craters found on Earth in years.
Fieldwork in October 2025 turned up shatter cones, distinctive fracture patterns in rock that form only under the extreme pressure of a cosmic impact. Researchers led by planetary geologist Gordon Osinski of Western University confirmed the 25-kilometer-wide structure, since named Uhackatik after consultation with the Innu Council of Ekuanitshit, was gouged out by an asteroid or comet roughly 390 million years ago.
It's the only unequivocal evidence of an impact event that you can see in the field with the naked eye.
Gordon Osinski, Western University
The largest find since Hiawatha
Uhackatik is now the largest impact structure identified since the 31-kilometer Hiawatha crater beneath Greenland's ice sheet was announced in 2018. Unlike Hiawatha, which required ice-penetrating radar to see at all, Uhackatik's outline was visible in ordinary satellite imagery, including a Landsat 8 image captured in October 2025 that shows Lake Marsal sitting near the center of a faint, weathered ring.
Getting a research team to the site was its own expedition: reaching the crater required a floatplane and wading through roughly 50 meters of water to examine the rock outcrops where the tall cliffs show columnar jointing and a central uplift, both hallmarks of a large impact structure that has since been softened by nearly 400 million years of erosion.
Osinski's team says a strike of similar size today would cause regional devastation on a scale capable of wiping out major cities, with climate effects felt well beyond the impact zone. Formal recognition of Uhackatik by the Meteoritical Society's nomenclature committee was pending as researchers prepared a fuller paper on the find.