In 2024 an amateur astronomer is looking at satellite images of Quebec. According to NASA his name is Joël Lapointe and he is looking for a place to camp. Around Lake Marsal the terrain draws a ring. The circle is about 25 kilometres across and its centre lies at 51.2 degrees north and 64.7 degrees west. The astronomer reports the shape to geologists.
The first scientific description is an abstract presented at the 88th Annual Meeting of the Meteoritical Society, number 5369. It has ten authors. The first is J. Gattacceca of CEREGE in Aix-en-Provence, the French centre for environmental geoscience. The authors include G. R. Osinski of the University of Western Ontario and C. A. Crow of the University of Colorado. A conference abstract does not go through peer review the way an article does. The NASA story about it was picked up by ScienceDaily on 22 September 2026.

In October 2025 an expedition reaches the structure and collects samples. At the centre the Grenvillian basement crops out, very old rocks of the Canadian Shield. In those rocks the geologists find shatter cones tens of centimetres long. A shatter cone is a striated, cone-shaped fracture that forms only under the pressure of an impact. Osinski, in the NASA story, calls it the only certain evidence of impact visible to the naked eye in the field.
Between 2 and 4 kilometres from the centre lies a rock known as the Marsal Breccia. It had been read as a diatreme, the pipe left by a volcanic explosion. The authors interpret it as impact melt rock, poor in fragments, up to 50 metres thick. It has the columnar jointing typical of melted rock as it cools. It holds blocks of basement up to half a metre across.
The abstract stresses how well the site is preserved. After hundreds of millions of years of erosion, the layer of melt rock is still more than 50 metres thick. The melt rock formed at the instant of impact, and it is the material on which the age is measured.

The age comes from two methods. The first is palaeomagnetism. When melted rock cools, some minerals lock in the direction of Earth’s magnetic field at that moment. Oriented cores drilled from the melt rock point to a period of reversed polarity, with magnetic north on the side of the south pole. The direction gives about 390 million years, within a range of 370 to 400. That is the Devonian.
The second method measures lead isotopes in zircon crystals from the melt rock. A laser vaporises a spot on the crystal and a mass spectrometer counts the atoms. The youngest zircons point to an age near 350 to 400 million years. The authors call the result preliminary.

The NASA story says the samples indicate an age of about 390 million years. It does not say the estimate is preliminary, or that the range runs from 370 to 400 million years. ScienceDaily’s headline speaks of a crater. The abstract speaks of an impact structure, the geologists’ term for an eroded crater of which only the root is left. According to NASA, Earth has about 200 confirmed impact structures. Again according to NASA, this is the largest found since Hiawatha, in Greenland, in 2018. The abstract makes neither comparison.
The structure already has a provisional name. Uhackatik was chosen, according to NASA, after consultation with the Innu Council of Ekuanitshit. An abstract by Rochette and colleagues in 2024 had already put forward Lake Marsal as a candidate. Confirmation on the ground came the following autumn.
The abstract ends with an observation. An impact structure 25 kilometres wide can still be discovered by looking at satellite images open to everyone.
The circle sat on public maps. It took the right pair of eyes.

References
Gattacceca J., Rochette P., Quesnel Y., Lagain A., Devouard B., Licht A., Osinski G.R., Darnault M., Seydoux A.-M., Crow C.A., «Uhackatik: a new 25-km diameter ~390 Ma impact structure in Quebec, Canada», 88th Annual Meeting of the Meteoritical Society, 2026, abstract 5369 (conference abstract, not peer reviewed), https://www.hou.usra.edu/meetings/metsoc2026/pdf/5369.pdf
NASA Earth Observatory, «An accidental impact crater discovery», republished by ScienceDaily on 22 September 2026 as «A strange circle on satellite maps turned out to be a 390-million-year-old impact crater».