Volcanic Eruptions and Asteroid Impact Caused Extinction of Dinosaurs, Says

Scientists still disagree on which event caused more widespread extinctions, but this new research makes it, well, academic.

The powerful asteroid impact thought to have wiped out the dinosaurs and the majority of other species alive a few 66 million years ago had help from massive volcanic eruptions that lasted for hundreds of thousands of years, according to a new study.

So the researchers traveled to India to the Deccan traps, where lava flows piled high reach about 3,000 meters in thickness, Renne said. For the longest time, scientists blame the six-mile asteroid for the extinction of prehistoric beasts 66 million years ago.

It would take Earth and its land and ocean life about 500,000 years to emerge from the devastation.

The study, conducted by Berkeley geologists, doesn’t rule out the asteroid collision theory, but it does put a slight twist to it. For years, scientists have been aware of the volcanism that was occurring in India during the same time period, which spread lava across a region known as the Deccan Traps. Even though the rate of lava flow more than doubled, the frequency of eruptions-as measured by the number of lava and soil layers-dropped. But U.C. Berkeley geophysicist Mark Richards offered words of consolation for those bemoaning the fate of the dinosaurs. Atmospheric effects are also hard to differentiate from each other as both events happened at the same time.

Renee is a professor-in-residence of earth and planetary science at UC Berkeley and is also director of the Berkeley Geochronology Center.

At such a big magnitude, the asteroid impact would have triggered the huge eruption of the Deccan Traps in India. This could have resulted in increased lava flow and the emission of harmful gasses in the atmosphere. “The scenario we are suggesting-that the impact triggered the volcanism-does in fact reconcile what had previously appeared to be an unimaginable coincidence”. He speculates that its effects rippled along the boundaries of nearby tectonic plates until they reached the volcanoes, expanding the size of subterranean magma chambers and thus increasing the volume of magma they could spew during any given eruption.

Although the asteroid impact would have caused massive disruption to the climate it would have been relatively short-lived compared to the long-term impacts caused by the Deccan Traps erupting for thousands of years, the scientists said.

The study was published this week in the journal Science. “It’s pretty important to say that both did happen, and both alone have the potential to be pretty devastating”, says Schoene. “Our data don’t conclusively prove that the impact caused these changes, but the connection looks increasingly clear”.

Earthquakes can induce volcanoes, Renne says, so his theory just takes that and scales it up. They wanted to see if any changes with the rock coincided with the asteroid impact. Citing this study, the Washington Post reported that initial eruption was not caused by the comet or asteroid though it could have intensified the event.