A 214-million-year-old impact crater, 100 km wide, now flooded to form an annular lake visible from space. The impact may have contributed to a mass extinction. The central island hasn't moved since the asteroid struck, frozen in geological time.
Copernicus Sentinel-2, ESA, CC BY-SA 3.0 igo, via Wikimedia Commons
An impact of cosmic proportions
Around 214 million years ago, during the Late Triassic period, a celestial body approximately 5 kilometers in diameter struck the Earth. The impactor, traveling at a velocity between 12 and 30 kilometers per second, released an immense amount of energy, creating one of the largest preserved impact craters on the planet surface. The initial crater was about 100 kilometers wide, though hundreds of millions of years of erosion and glacial scouring have since reduced its visible diameter to about 72 kilometers.
The immediate aftermath of the impact produced a complex crater with a central peak. This peak, now known as Mount Babel, formed as the crust rebounded from the shock of the collision. This process uplifted ancient Precambrian basement rocks, primarily anorthosite and gneiss, from deep within the crust. The geology of the crater floor shows evidence of the event, including sheets of solidified impact melt rock and shock metamorphic features like shatter cones and shocked quartz.
The modern Eye of Quebec
For most of its history, the Manicouagan crater was a terrestrial feature. Its transformation into the striking annular lake visible today is modern. In the 1960s, Hydro-Québec began construction on a massive hydroelectric project, which included the Daniel-Johnson Dam. Completed in 1970, this multiple-arch buttress dam—the largest of its kind in the world—impounded the Manicouagan River. The rising waters flooded two crescent-shaped lakes, Mouchalagane and Manicouagan, merging them into a single ring-shaped reservoir.
This flooding created René-Levasseur Island from the crater's central uplifted plateau. With an area of 2,020 square kilometers, the island is larger than the lake that surrounds it. Its distinct circular shape makes the entire structure easily identifiable from orbit, earning it the nickname "Eye of Quebec" and making it a favorite landmark for astronauts to photograph.
The timing of the Manicouagan impact has led to scientific investigation about its connection to mass extinctions. U-Pb zircon dating places the impact at 214 ±1 million years ago. This is approximately 12 million years before the major Triassic-Jurassic extinction event, ruling it out as a direct cause. Some research suggests it may have contributed to an earlier, smaller extinction event during the Carnian/Norian boundary or a die-off of radiolarian plankton species.
💡Fun Facts
The distinct shape of the Manicouagan Reservoir makes it a common visual landmark for astronauts orbiting the Earth.
The central peak, Mount Babel, rises 952 meters and is composed of ancient rocks uplifted by the impact.
The Daniel-Johnson Dam, which created the reservoir, is composed of 14 buttresses and 13 arches.
A discredited hypothesis once suggested the Manicouagan impact was part of a chain of impacts that happened simultaneously, but precise dating of other craters has since disproven this.
The area is a remote, natural wilderness, accessible year-round, but road conditions on Route 389 can be hazardous, especially in winter.
Admission
Access to the region is free. Fees apply for lodging at Uapishka Station or for guided tours and activities.
Accessibility
The region is remote and requires a vehicle. Route 389 from Baie-Comeau is the primary access road. The terrain is mountainous and rugged. The best views are from the air or from viewpoints along the highway and hiking trails in the Uapishka (Groulx) Mountains.
