Manicouagan crater

The Manicouagan Crater is one of the oldest known impact craters and is the largest 'visible' impact crater on Earth, located primarily in Manicouagan Regional County Municipality in the Côte-Nord region of Québec, Canada, about 300 km (190 mi) north of the city of Baie-Comeau. At roughly 213-215 million years old, Manicouagan is one of the oldest large astroblemes still visible on the surface. Its northernmost part is located in Caniapiscau Regional County Municipality. It is thought to have been caused by the impact of a 5 km (3 mi) diameter asteroid about 215.5 million years ago (Triassic Period). It was once thought to be associated with the end-Carnian extinction event.

It has been suggested that the Manicouagan crater may have been part of a multiple impact event which also formed the Rochechouart crater in France, Saint Martin crater in Manitoba, Obolon' crater in Ukraine, and Red Wing crater in North Dakota. Geophysicist David Rowley of the University of Chicago, working with John Spray of the University of New Brunswick and Simon Kelley of the Open University, discovered that the five craters appeared to form a chain, indicating the breakup and subsequent impact of an asteroid or comet, similar to the well observed string of impacts of Comet Shoemaker-Levy 9 on Jupiter in 1994.