In a paper published Friday in Science Magazine, UC Berkeley researchers came closer to settling a scientific debate over what killed the dinosaurs millions of years ago.
For decades, scientists have questioned whether the ultimate cause of the Cretaceous-Tertiary extinction, or K-T extinction, at the end of the cretaceous period was the impact of a large meteorite or massive volcanic eruptions in India’s Deccan Traps. Paul Renne, lead researcher and director of the campus Geochronology Center, said the researchers’ work shows that the two events were related.
Seismic waves from the impact of the 6-mile-wide meteorite that is believed to have struck the Yucatan Peninsula accelerated volcanic activity in the Deccan Traps, contributing to the mass extinction, according to Renne.
Using argon-argon dating to analyze samples they collected from various parts of the Deccan Traps’ lava flows, researchers were able to show that larger volcanic pulses coincided with the meteorite impact, suggesting that the meteorite impact enhanced volcanism in the Deccan Traps.
“One of the important things about our study is that this is the most precise argon-argon study ever conducted on the Deccan Traps,” said Courtney Sprain, a campus doctoral candidate and co-author of the paper.
The method has an uncertainty of 100,000 years on a scale of millions, which is much more precise than previous attempts by scientists.
While the study did not examine possible mechanisms of the extinction such as climate change, toxic gases or dust particles, major meteorite impacts and volcanic activity could have similar effects on the global ecosystem, producing greenhouse gases — aerosols of sulfur or large amounts of dust that block sunlight.
Renne noted the power of massive eruptions to disrupt the global environment, such as a 1783 eruption in Iceland that released enough sulfur into the atmosphere to lower the temperature of the northern hemisphere by one degree Celsius for a year.
Current and future research in the field, according to Renne, will focus on increasing the precision of the dates using the argon-argon method and better understanding how an impact could accelerate the activity of an existing volcanic system.
“We don’t know exactly how physically a meteor impact and the seismic waves from the impact could have caused an acceleration of volcanism at the Deccan Traps,” said Mark Richards, co-author of the paper and campus professor at the earth and planetary science department.
Renne said the findings have not laid to rest the arguments about the cause of extinction, but they have made clear that volcanic activity was a significant contributing factor.
“I think it’s the next big step,” said Charles Marshall, director of the UC Museum of Paleontology. “Because what it says is that the volcanism only became a major contributor to climate change after the meteor impact.”
A previous version of this article incorrectly stated that dinosaurs went extinct billions of years ago. In fact, they were killed millions of years ago.