Keller: Volcanoes, not asteroid, caused mass extinction

Keller based her controversial findings on studies of rock formations from the K-T boundary — the transition between the Cretaceous and Tertiary periods — which marks Earth’s development from being dominated by reptiles to being occupied by mammals. Keller looked at formations from around the world, including some in the United States, India and Mexico. Her research included examining ossified remains of various organisms that indicate a delay between when the asteroid hit the Earth and the extinction of the dinosaurs.

“For thirty years many scientists have taken it for granted that the K-T mass extinction was caused by an asteroid impact,” Keller said in an e-mail to The Daily Princetonian. “The search for the real culprit must now begin in earnest.”

Keller’s work contributes to the debate about the true cause of the extinction of the dinosaurs. For years, scientists have theorized that the Chicxulub asteroid event, whose crater was discovered in northeastern Mexico in the late 1970s, precipitated the demise of the dinosaur population, as well as more than half of all living organisms on Earth.

Part of Keller’s research, however, looks at “the cores from the impact crater on Yucatan” and shows that the Chicxulub impact — the earliest known asteroid event in northeastern Mexico — actually occurred hundreds of thousands of years before the first evidence of mass dinosaur extinction, she said.

“Our work shows that the long-held belief that a large asteroid impact on the Yucatan caused the mass extinction some 65 million years ago is not supported by critical evidence,” Keller explained.

Keller added that the Chicxulub asteroid did not even cause any significant damage to the planet’s environment or fragile marine species either.

Keller emphasized her confidence in her research, especially in light of its enormous impact on the scientific community.

“Challenging the established and popular impact theory requires extraordinary proof,” she said. “We have provided that proof in triplicate.”

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Keller conducted a significant portion of her research at El Penon, a trench site in northeastern Mexico. Several Princeton students assisted with the excavation.

Brian Gertsch GS, who has been working with Keller, said he was currently studying the biotic effects of Deccan volcanism in marine environments in northeast India.

“The main results show that very high stress conditions in marine environments correlate with a major volcanic episode in the terminal Cretaceous [period] in India,” he said in an e-mail.

Gertsch added that his work with Keller points to a significant, direct impact of the Deccan volcanic phase at the K-T boundary on the environment, both on land and in the oceans.

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“This scenario provides a better view of the K-T mass extinction mechanism where extraterrestrial impact had no influence on the faunal mass extinction,” Gertsch explained.

Keller noted that there is room for further research in the field, explaining that since the Chicxulub asteroid event should no longer be considered the cause of the mass extinction of the organisms which populated the Earth during the Cretaceous period, the cause of their extinction remains to be determined.

Keller and her team have already begun to work on answering this question, she said.

“We have already discovered that the main volcanic phase [of huge-scale volcanic activity in modern-day India] coincided with the mass extinction,” she said. “The next step is to find out how these volcanic eruptions caused the global mass extinction.”