"This extinction happened at a geological instant in time," says Sam Bowring, the Robert R. Shrock Professor of Geology in MIT's Department of Earth, Atmospheric and Planetary Sciences. "There's no question the extinction occurred at the same time as the first eruption."
The paper's co-authors are Terrence Blackburn (who led the project as part of his PhD research) and Noah McLean of MIT; Paul Olsen and Dennis Kent of Columbia; John Puffer of Rutgers University; Greg McHone, an independent researcher from New Brunswick; E. Troy Rasbury of Stony Brook University; and Mohammed Et-Touhami of the Universit Mohammed Premier Oujda in Morocco.
More than a coincidence
The end-Triassic extinction is one of five major mass extinctions in the last 540 million years of Earth's history. For several of these events, scientists have noted that large igneous provinces, which provide evidence of widespread volcanic activity, arose at about the same time. But, as Bowring points out, "Just because they happen to approximately coincide doesn't mean there's cause and effect." For example, while massive lava flows overlapped with the extinction that wiped out the dinosaurs, scientists have linked that extinction to an asteroid collision.
"If you really want to make the case that an eruption caused an extinction, you have to be able to show at the highest possible precision that the eruption of the basalt and the extinction occurred at exactly the same time," Bowring says.
In the case of the end-Triassic, Bowring says researchers have dated volcanic activity to right around the time fossils disappear from the geologic record, providing evidence that CAMP may have triggered the extinction. But these estimates have a margin of error of 1 million to 2 million years. "A million years is foreve
|Contact: Sarah McDonnell|
Massachusetts Institute of Technology