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.
Read more about this topic: Manicouagan Crater
Famous quotes containing the words multiple, impact and/or event:
“There is a continual exchange of ideas between all minds of a generation. Journalists, popular novelists, illustrators, and cartoonists adapt the truths discovered by the powerful intellects for the multitude. It is like a spiritual flood, like a gush that pours into multiple cascades until it forms the great moving sheet of water that stands for the mentality of a period.”
—Auguste Rodin (1849–1917)
“Too many existing classrooms for young children have this overriding goal: To get the children ready for first grade. This goal is unworthy. It is hurtful. This goal has had the most distorting impact on five-year-olds. It causes kindergartens to be merely the handmaidens of first grade.... Kindergarten teachers cannot look at their own children and plan for their present needs as five-year-olds.”
—James L. Hymes, Jr. (20th century)
“In the event of an oxygen shortage on airplanes, mothers of young children are always reminded to put on their own oxygen mask first, to better assist the children with theirs. The same tactic is necessary on terra firma. There’s no way of sustaining our children if we don’t first rescue ourselves. I don’t call that selfish behavior. I call it love.”
—Joyce Maynard (20th century)