March 20, 2008
Scientists: Volcanic Gases to Blame for Mass Extinctions
Scientists reported on Thursday that they believe a series of volcanic eruptions in modern day India may have been the cause of mass extinctions of species including dinosaurs over the last 545 million years.
The eruptions, which formed "flood basalts," hurled large amounts of sulfur into the atmosphere 65 million years ago during the Cretaeceous period and resulted in damages to the Earth's climate, according to researchers. These eruptions are one of two primary explanations for a series of mass extinctions throughout history.
The second, and most adhered to, theory claims that it was asteroids the caused the extinction of dinosaurs and other species.
Until now, scientists have been unable to measure the amount of toxicity from the volcanic gases, but a team of British scientists found rare glass in the Deccan rock which preserved crucial information about its gas content, according to their report in the journal Science.
The amount of sulfur released by the volcanoes may have been 10 times as much as humans have released by burning coal in power stations and would be likely to have a "severe" impact on the Earth's climate.
"It certainly bolsters the case, though it doesn't prove it," Stephen Self, senior volcanologist with the U.S. Nuclear Regulatory Commission, said.
"There have been several major mass extinctions and most of those have, uncannily, occurred while one of these huge flood basalt provinces was being formed."