A Quebec amateur astronomer was scouting a campsite using satellite imagery in 2024 when he spotted a 25-kilometre ring around Lake Marsal, and geologists who reached it by floatplane the following year found shatter cones confirming a roughly 390-million-year-old impact structure now provisionally named Uhackatik

In 2024, the amateur astronomer was planning a camping trip in Quebec’s Côte-Nord region and scrolling through satellite imagery when a nearly circular pattern of ridges caught his attention, arranged around a body of water called Lake Marsal. The feature was roughly 25 kilometres across, large enough that it should have been an obvious landmark, yet it did not correspond to any catalogued geological structure. Lapointe was not the first person to notice unusual terrain on a map and wonder about its origin, and most such observations turn out to be nothing. What made this one different is that there was a specific place to send it: a public reporting channel built by a research group that spends its time fielding exactly these kinds of tips. A screening database built for exactly this kind of tip Lapointe submitted his find through Impact Earth, a project run out of Western University’s Department of Earth Sciences by planetary geologist Gordon Osinski, who also maintains the associated impact-crater database. Osinski has said he receives frequent submissions from members of the public convinced they have spotted a crater, and that the overwhelming majority, as he put it to ZME Science, “turn out not to be the case.” Lapointe’s ring was one of the rare exceptions that survived that first filter and warranted an actual field visit. Reaching the ring took a floatplane and a long wade through water The team that eventually confirmed the structure — four researchers including Osinski and French geophysicist Pierre Rochette — flew into the site by floatplane in October 2025. According to Earth.com’s reporting, the aircraft could not get close enough to shore, forcing the researchers to wade through roughly 50 metres of water while carrying their equipment. Osinski, who has led geological expeditions across six continents and to the Arctic, described the trip to Live Science as “one of the most arduous expeditions I’ve ever done. Once on the ground, the terrain matched what satellite images had hinted at from orbit: a ring of raised, structurally deformed rock consistent with a complex impact crater, the kind that develops a central uplift when a large enough object strikes at high speed. Confirming that visual impression required physical evidence collected by hand, from actual outcrops — something satellite imagery alone cannot provide. Shatter cones are the evidence that turns a ring into a crater The rock feature the team was hunting for is called a shatter cone: a branching, cone-shaped fracture pattern etched into rock by the passage of an extremely high-pressure shockwave. Shatter cones do not form from volcanic activity, erosion, glacial scouring or any other ordinary geological process capable of producing a circular landform, which is why geologists treat them as close to definitive. Osinski has called them, in comments reported by Earth.com, “the only unequivocal evidence of an impact event that you can see in the field with the naked eye.” Alongside the shatter cones, the team documented cliffs of impact melt rock roughly four kilometres from the structure’s centre. Impact melt forms when the heat and pressure of a collision are intense enough to liquefy the target rock outright, which then cools and recrystallizes into a distinct texture rarely produced any other way, as Space.com’s coverage of the expedition explains. Together, the shatter cones and the melt rock are the kind of layered physical evidence that separates a confirmed impact structure from a merely suggestive shape on a map — a distinction that matters, because ring-like landforms can also arise from volcanic calderas, salt domes or plain erosion, none of which produce shatter cones. Provisionally named Uhackatik, formal recognition still pending After consulting the Innu Council of Ekuanitshit, whose traditional territory includes the area, the research team is calling the structure Uhackatik. Laboratory analysis of the collected rock samples places the impact in the Devonian period, roughly 390 million years ago. That figure describes when the impact happened. The crater’s present, softened shape is a separate story: 390 million years of erosion, glaciation and vegetation growth have reduced what was once a sharp-edged crater into the ring of ridges Lapointe noticed on a map. The team considers the impact origin essentially settled based on the shatter cones and melt rock, but the finding is not yet official. Per ZME Science, the researchers plan to present their results at the 88th Annual Meeting of the Meteoritical Society in Frankfurt, Germany, where a dedicated committee is expected to formally ratify Uhackatik’s status as a recognized impact structure. At an estimated 25 kilometres across, it would be the largest crater reported anywhere since Greenland’s 31-kilometre Hiawatha structure — itself an ice-buried, still-debated find from 2018. Why a hole in the Quebec bush matters for planetary science Impact cratering is a defining process across the Solar System, not just a footnote in Earth’s geological history. Western University’s Impact Earth project describes it as “one of the most important and fundamental geological process in the Solar System.” Every rocky body has been struck repeatedly since its formation, but the record of those strikes survives very unevenly. According to figures cited by ABC News, roughly 200 impact craters have been confirmed on Earth in total, compared with an estimated two million-plus on the Moon. The gap exists because Earth actively erases its own scars: plate tectonics recycles crust, weathering and glaciers grind down rims, and vegetation and sediment bury what is left. The Moon has none of those processes, so a crater formed there billions of years ago can look almost as fresh today as the week it formed. That imbalance is precisely why finds like Uhackatik carry weight beyond Quebec. With so few terrestrial impact structures available for direct, hands-on study, each new confirmed crater adds to a small dataset that planetary scientists use to understand cratering mechanics — central uplift formation, melt-sheet behavior, shock deformation — that are otherwise studied mainly through remote imagery of the Moon and Mars, where no one can walk up and check a rock face for shatter cones. Osinski’s own work makes the link explicit: beyond running Impact Earth, he helps train NASA’s Artemis astronauts in impact geology at Mistastin (Kamestastin) crater in Labrador, a Canadian structure chosen specifically because its shocked, melt-rich terrain resembles what astronauts will encounter on the lunar surface. A crater like Uhackatik is built from the same physical evidence, and reasoned about with the same tools, that scientists rely on to read the impact history of worlds no one has ever set foot on — evidence that here, unusually, can be reached on foot.