It is widely believed that an asteroid wiped out the dinosaurs, but new research suggests a volcano that erupted before impact may have contributed to the mass extinction.
Researchers looked at the age of rocks from the Deccan Traps in India, which is a region characterized by an ancient volcanic eruption that was believed to be the largest ever to occur on Earth, MIT news reported. The researchers collected more than 50 samples of rocks from the region, and found those from both the bottom and top of the traps contained zircon; this allowed the researchers to make conduct an ultra-precise analysis of when the rocks were formed.
Based on the analysis the researchers determined the eruption began 250,000 years before the asteroid strike and continued on for 500,000 years after the impact. This event may have released dangerous levels of volatile chemicals into the air, which would have also contaminated the ocean.
"If models of volatile release are correct, we're talking about something similar to what's happening today: lots of carbon dioxide being emitted into the atmosphere very rapidly," said Michael Eddy, a graduate student in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "Ultimately what that can do is lead to ocean acidification, killing a significant portion of plankton - the base of the food chain. If you wipe them out, then you'd have catastrophic effects."
While the researchers are unsure of the exact mechanisms involved, the volcano most likely made a significant contribution to the extinction of the dinosaurs.
"I don't think the debate will ever go away," says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "The [asteroid] impact may have caused the extinction. But perhaps its effect was enhanced because things were softened up a bit by the eruption of these volcanoes."
