‘Direct cause of extinction of dinosaurs was asteroid,’ say researchers

New research has found that the most direct cause of the extinction of dinosaurs, which once ruled the Earth, was a collision with an asteroid. For a long time, the scientific community has been sharply divided between the two groups over the cause of dinosaur extinction – “collision with the asteroid” or “explosions of volcanoes.” The newly revealed research is garnering attention for proposing the most convincing grounds to end the long-standing controversy.

A research team led by Pincelli Hull, assistant professor of geology and geophysics at Yale University, published its research results on international journal “Science” on Friday, claiming that the large-scale emission of volcanic gas that took place 66 million years ago – around the time when dinosaurs became extinct – is irrelevant to the mass extinction as it happened 200,000 years before the Earth’s collision with the asteroid.

During this period sitting between the Cretaceous Period of the Mesozoic Era and the Paleogene Period of the Cenozoic Era, not only dinosaurs but also 75 percent of all terrestrial species disappeared. Scientists have suspected that a collision with the asteroid during this period had caused sudden environmental changes, which led to the mass extinction.

Hull’s research team investigated when volcanic gas – carbon dioxide – was emitted and caused global warming to find out whether the explosions of volcanoes had an impact on the mass extinction. According to the team, a large amount of volcanic gas was released 200,000 years before the asteroid’s collision with the Earth. The volcanic activities raised the Earth’s temperatures by two degrees Celsius, but it only caused most animals to migrate to the Arctic and the Antarctic where temperatures are lower, not to become extinct.

“A lot of people have speculated that volcanoes mattered to K-Pg (Cretaceous–Paleogene extinction event), and we're saying, 'no, they didn't,’” says Hull, claiming that the only cause of the extinction was the asteroid collision.


shinjsh@donga.com