Volcanism didn’t play a role in demise of dinosaurs

Jan. 16 (UPI) — Through the decades, scientists have considered a number of possible causes for the disappearance of the dinosaurs, but as of late, the idea is that both a massive meteor collision and a period of intense volcanism precipitated the demise of the dinosaurs.

New research, however, suggests the volcanic activity in question occurred well before, and was unrelated to, the mass extinction event that killed the dinosaurs.

The findings, published Thursday in the journal Science, run counter to several recent studies that have detailed the timing of the eruption of India’s Deccan Traps. This volcanic activity and its impacts of Earth’s climate, many scientists have theorized, was just as important as the meteor that struck the Yucatan Peninsula in snuffing out the dinosaurs 66 million years ago.

But according to the authors of the latest Science paper, earlier studies had the timing wrong — not because scientists messed up their math, but because they were measuring the timing of lava flows instead of gas emissions.

“Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world,” Pincelli Hull, an assistant professor of geology and geophysics at Yale University, said in a news release. “But recent work has focused on the timing of lava eruption rather than gas release.”

Researchers measured the carbon isotopes from marine fossils to estimate changes in temperature in the ancient oceans. Scientists compared their paleotemperature records with models simulating the effects of CO2 release on Earth’s climate. The analysis showed most of the outgassing from the Deccan Traps happened well before the mass extinction event.

“Volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction,” said former Yale researcher Michael Henehan. “A number of species moved toward the North and South poles but moved back well before the asteroid impact.”

Previous studies have also revealed evidence of heightened volcanism in the wake of the dinosaur’s extinction, but no evidence of global warming. Authors of the new study suggest the loss of the dinosaurs and other species likely blunted the climatic impacts of volcanic activity.

“The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle,” said Yale postdoctoral associate Donald Penman. “Our results show that these changes would allow the ocean to absorb an enormous amount of CO2 on long time scales — perhaps hiding the warming effects of volcanism in the aftermath of the event.”