Trending Science: Dinosaurs didn’t go extinct because of volcanoes

Was it the asteroid or a volcano that began the demise of the dinosaurs 66 million years ago? In recent years, scientists have been claiming that both a massive meteor collision and a period of intense volcanism triggered the dinosaurs’ downfall.

Research published in the journal ‘Science’ is ready to put the debate to rest once and for all. It’s the asteroid that slammed into Earth and wiped out the dinosaurs and most life on the planet. The study shows that any climate change from the volcanic eruptions and lava flows that occurred in the Deccan Traps (modern-day India) happened well before the mass extinction event referred to as K-Pg.

Volcano’s effect and timing don’t match up

“A lot of people have wanted to argue that both the impact and the volcanism mattered in the extinction,” lead author Pincelli Hull, an assistant professor of geology and geophysics at Yale University, told ‘The New York Times’. “And what we’re seeing is, it doesn’t look like it. It’s just the impact.”

“A lot of people have speculated that volcanoes mattered to K-Pg, and we’re saying, ‘no, they didn’t’,” Prof. Hull told ‘CNN’. “What our study does is take 40 years of research and adds a bunch of new research. It combines this in the most quantitative tests you can do and it really doesn’t look like it (was the volcanoes).”

The international research team modelled the effects of carbon dioxide and sulfur emissions on global temperatures and compared them with palaeotemperature records that spanned K-Pg. It found that over 50 % of the emissions from the volcanoes that released gases like sulfur dioxide and carbon dioxide from the Deccan Traps took place long before the asteroid impact. Only the impact coincided with K-Pg.

The asteroid is the culprit

“Volcanic activity in the late Cretaceous [period] caused a gradual global warming event of about two degrees, but not mass extinction,” said co-author Michael Henehan, a geochemist at the GFZ German Research Centre for Geosciences who gathered the palaeotemperature records.

Henehan used proxy records based on several sources, including chemical traces in fossils, to determine the variations in temperature at that time. In addition, the researchers investigated cores of rock obtained from the seafloor that indicated when the asteroid hit. “You can see impact — melted fragments of rock. It’s really, really clear on these cores of rock,” said Henehan.

Prof. Hull is confident the murder mystery is finally solved. The debate over what killed the dinosaurs doesn’t need to rage on. “If someone came up with compelling evidence tomorrow, I’d be prepared to say we are wrong. But it really doesn’t look like it based on what we know today,” she concluded.