Manicouagan Crater - Hypothetical Multiple Impact Event

Hypothetical Multiple Impact Event

It has been suggested that the Manicouagan crater may have been part of a hypothetical 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 formed 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.

Kelley had developed a technique to precisely date impact craters, using laser argon-argon dating of the glass formed by the impacts, and cited stratigraphic evidence to support an older age of 215 ± 25 Myr (Late Triassic). He and Kelley sought Rowley's help to determine how the craters were aligned when the impacts occurred, since—due to plate tectonics—the locations have moved large distances in the intervening 214 million years. Three of the craters—Rochechouart, Manicouagan and Saint Martin—formed a 5,000 km (3,100 mi) chain at latitude 22.8° N, while Obolon' and Red Wing lay on identical declination paths with Rochechouart and Saint Martin respectively. All of the craters had previously been known and studied, but their paleoalignment had never before been demonstrated. Rowley has said that the chance that these craters could be aligned like this due to chance are nearly zero.