A satellite map revealed a mysterious giant circle that was hiding in Canada for 390 million years. One amateur astronomer finally noticed it

While trying to find a suitable place for camping in an unknown part of Quebec, Canada, scientists came across something far more ancient than expected – a 25-km-wide impact crater that is estimated to be around 390 million years old.

The peculiar geological formation was spotted by an amateur astronomer Joël Lapointe in 2024 when he was studying satellite images of the Côte-Nord province. A giant circle near Lake Marsal caught his attention and raised a question: is it the leftover from a meteorite impact that happened long ago?

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The discovery of Joël Lapointe urged scientists to travel to the site.

In October 2025, the team led by the planetary geologist Gordon Osinski of Western University reached the remote location.

One of the most important pieces of evidence of impact crater origin that scientists have found in the area is the shatter cones – geological formations created under the pressure of impact.

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If the newly found geological structure is recognised as an impact crater by the Meteoritical Society, then it may become the greatest discovery since the discovery of the 31-km-wide impact structure of Hiawatha in Greenland in 2018.

A strange circle catches an amateur astronomer's eye

It all started with an observation that might have gone unnoticed.

Lapointe was looking at satellite maps on the internet while preparing for his journey to Côte-Nord, Quebec, when he saw a round object near Lake Marsal. The shape was unusual enough to raise a question: could it have been produced by an impact from space?

Lapointe contacted researchers in Europe and North America about the feature. His inquiry helped attract attention from scientists studying possible impact structures.

At a 2024 meeting of the Meteoritical Society, French researchers identified the Lake Marsal area as the centre of a potential impact structure.

The possibility remained unconfirmed, however. Circular geological formations can have several origins, including volcanic activity, erosion and tectonic processes.

That uncertainty meant scientists needed physical evidence from the ground.

Planetary geologist Gordon Osinski initially approached the idea cautiously. He eventually organised a field expedition to investigate the location directly.

The journey from satellite image to geological evidence would take the team into one of the more difficult field environments they had encountered.

Scientists trek into difficult Quebec terrain

However, getting to the crater was not easy.

In October 2025, Osinski and his team travelled by floatplane, but the plane could not land at the shoreline; the researchers, together with their equipment, had to walk more than 50 metres of water.

However, dense vegetation, boggy soil and hard terrain did not make exploration any easier.

Earlier geological studies of the area have provided another interpretation of the rocks found there. In particular, some of the breccia found in the area has been taken to be evidence of a diatreme – funnel-shaped geological formation characteristic of explosive volcanism.

However, shortly after the beginning of the expedition, scientists received new evidence.

The unusual structures found inside the exposed geological formations included shatter cones – geological structures that are created by the shockwaves from an extremely powerful impact propagating through the rock.

This is one of the best geological indicators of an impact.

For Osinski, finding them meant changing the interpretation of the entire site.

It became clear that the circular structure seen from above is not a remnant of the volcanic system of antiquity. This was the mark of an enormous collision between our planet and an extraterrestrial body.

Shatter cones expose the crater's violent past

The structure, thought to be an impact crater, is approximately 25 kilometres across. Geologists have also identified the presence of a central uplift as well as cliffs with signs of columnar jointing.

Geologists estimate that the crater originated around 390 million years ago, during the Devonian Era.

The Earth at that time would have been quite unlike what it looks like now. An impact of this magnitude could have produced large amounts of energy, thus leaving behind traces of its shock.

Thus, the discovery gives some insight into how impact craters dating back hundreds of millions of years are able to stay buried on Earth.

The surface of Earth is always undergoing the process of erosion, tectonics, sedimentation and even vegetation, thus covering up the impacts of any past events.

Unlike the Moon, where impact craters are evident, the Earth continuously remakes its own surface, thus hiding ancient structures from view.

Scientists have positively identified only about 200 impact structures on Earth, while a lot more are probably waiting to be discovered.

The crater was named Uhackatik after discussions with the Innu Council of Ekuanitshit. The Meteoritical Society will soon make the identification formal.

A satellite image became the starting point for a major discovery

The crater's discovery is unusual not only because of its age and size, but because of how the investigation began.

Lapointe was not conducting a professional geological survey when he spotted the circular feature. He was looking for a place to camp.

His observation eventually triggered a chain of events involving amateur astronomy, satellite imagery, geological research and a difficult field expedition.

The discovery also highlights the role that publicly available mapping technology can play in modern science. Large geological structures can sometimes be difficult to spot from the ground but become obvious when viewed from above.

For scientists searching for impact structures, those unusual shapes can provide the first clue.

The researchers now have another site to study as they work to understand when the impact occurred, how the crater formed and what it can reveal about Earth's geological history.

The location is unlikely to become a popular astronaut training site. Osinski, who is part of NASA's Artemis Geology Team, has noted that the area's remoteness and difficult terrain make access particularly challenging.

A younger impact structure at Labrador's Kameshtashtan, also known as Mistastin Lake, has already been used for astronaut geology training because it is considerably easier to reach.

For Lapointe, however, the significance of Uhackatik began with something much simpler: noticing that a strange circle on a satellite map might be worth investigating.

A feature that had remained part of the Quebec landscape for hundreds of millions of years finally had someone looking closely enough to ask what it was.

FAQ

1. How old is the new impact crater in Quebec?

The researchers have estimated that the age of the Uhackatik impact structure is about 390 million years old, during the Devonian era.

2. What is the size of the crater?

It measures about 25 kilometres (16 miles) in diameter and thus belongs to the bigger ones on our planet.

3. How do scientists prove that this feature is indeed an impact crater?

In the local rocks, scientists managed to find some shatter cones, which are the product of the very intense shock pressure caused by an impact event.

4. Who discovered the crater?

It was first detected in satellite images by the amateur astronomer Joël Lapointe, who looked for good camping sites in Quebec.