What if a shape noticed while planning a camping trip turned out to be the scar of an asteroid impact? That is the path from a curious map search to Uhackatik, a broad circular structure in Quebec that researchers now attribute to a collision roughly 390 million years ago.
The feature sits near Lake Marsal in the remote Côte-Nord region. From above, its outline is subtle: forest, lakes and ridges blur together until the eye begins to follow the ring. An amateur observer, Joël Lapointe, noticed the pattern in online satellite maps in 2024 and asked specialists whether it might be an impact structure.
The question mattered because a circle on a map is only a starting clue. Erosion, glaciation and volcanic activity can all make landscapes look round. A satellite image can suggest a hypothesis, but it cannot by itself prove what made the ground.
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The first explanation was volcanic
Earlier geological maps had interpreted breccia in the area as a diatreme—a funnel-shaped body of broken rock produced by an explosive volcanic process. That explanation was plausible enough to be the working model. To test the alternative, Gordon Osinski of Western University organised a field expedition in October 2025 with colleagues from Canada and France.
The team reached the site by floatplane. The last stretch was not a simple walk to an outcrop: researchers had to wade through about 50 metres of water carrying equipment, then work through swampy ground and thick vegetation. The remote setting explains why a structure visible in public imagery could remain outside the confirmed crater record for so long.
What does an impact leave in rock?
The most persuasive clue was not the circle itself. It was a set of shatter cones found in the rock. These are cone-shaped fractures whose surfaces carry radiating striations. They form under the intense shock of a hypervelocity impact and are among the few impact indicators that can be recognised in the field without a microscope.
The researchers also examined impact-melt rock and the structure’s larger shape. NASA’s Earth Observatory describes a complex feature about 25 kilometres across, with a central uplift and steep cliffs marked by columnar jointing. Those details fit a large collision better than a small volcanic pipe, but the evidence still has to be assessed through the formal process used to recognise impact structures.
The distinction is useful. A meteor is the streak of light we see when a space rock enters an atmosphere; a meteorite is a piece that reaches the ground. The event that excavates a basin is an impact, and the geological structure can survive long after the projectile has been eroded away. Curiosmos has previously explained the difference between a meteor, meteoroid and meteorite.
How old is Uhackatik?
Rock samples indicate an age of about 390 million years. That number does not come from the shape visible in the satellite image; it comes from the rocks and the geological relationships preserved inside the structure. Dating is one reason field evidence matters. A broad depression can be ancient, recent or unrelated to an impact, while mineral changes produced by shock and melting can carry a more specific record.
At that age, the structure predates many landscapes familiar from human history by hundreds of millions of years. It is also old enough for erosion and later geological processes to hide much of the original crater. NASA notes that the object that made it would have been large enough to create regional devastation and global climate effects if an equivalent collision occurred today. That is a comparison of scale, not a reconstruction of a particular ecosystem or extinction event at Lake Marsal.
Why is the name important?
The research team is calling the structure Uhackatik after consulting the Innu Council of Ekuanitshit. Naming a geological feature is not only a technical label. It places the site in a living cultural landscape and records how the community connected to the land was involved in the decision.
The structure is regarded by the researchers as essentially confirmed, but NASA reports that a Meteoritical Society committee is expected to formally recognise it at a future meeting. That wording is worth keeping. The field evidence can be strong while the administrative status remains one step behind the discovery.
What can a map—and a map cannot—tell us?
The story begins with a freely available image, but the important work happened after the screen. The satellite view revealed a pattern. Geologists compared it with maps and older samples. A field team travelled to the site, documented shock features and collected rocks. Specialists then had to separate an impact explanation from the volcanic interpretation and estimate when the event occurred.
That sequence is a useful reminder for anyone who studies unusual landscapes. Remote sensing is powerful because it shows relationships that are difficult to see from the ground. It is limited because several processes can produce similar shapes. The strongest conclusion comes when the view from above agrees with the evidence held in the rocks.
There are roughly 200 confirmed impact structures on Earth, while geologists estimate that many more remain undiscovered. Curiosmos has looked at one of Earth’s oldest confirmed impact craters; Uhackatik adds a different lesson. Sometimes the next crater is not found by a dedicated survey. Sometimes it begins with a person asking why a lake has the shape it does.
The final question is still open in a productive way: what other circular features are waiting for someone to compare a satellite image with the rocks beneath it?
