URI research throws ‘wrinkle in time’ into dinosaur extinction story

May 26, 2020 5:25 pm

KINGSTON, R.I. (WLNE)– The popular theory of how dinosaurs went extinct usually holds that an asteroid collided with the Earth’s surface, creating a mass extinction almost instantaneously.

In recent years, some scientists have said volcanoes spewing forth gases that contributed to climate change may have also led to a mass extinction; while another camp has sought to link the two theories together.

But scientists at the University of Rhode Island have published a paper in the journal Geology that puts a wrinkle into those theories, at least for one mass extinction event that occurred among ancient Late Triassic vertebrates.

The scientists say there was no sudden mass extinction, and the fossil record shows dinosaurs and other large vertebrates went extinct over the course of 10 million years, sometime between 222 million and 212 million years ago.

A team of scientists led by graduate student Reilly Hayes analyzed fossils in Arizona’s Petrified Forest National Park to reach their conclusions.

URI geosciences professor David Fastovsky said the national park offered unique conditions and fossils to conduct the painstaking research.

Fossils analyzed included “crocodile-like phytosaurs, armored aetosaurs, early dinosaurs, large crocodile-like amphibians, and other land-dwelling vertebrates,” according to a statement form the university.

“In the end, we concluded that neither the asteroid impact nor the climate change had anything to do with the extinction, and that the extinction was certainly not as it had been described – abrupt and synchronous,” Fastovsky said.

The research doesn’t dispute that an asteroid struck the earth, or that climate change occurred in the years following. But it does change the time frame for when extinctions began– for some dinosaur species, a process that began 2 to 3 million years before the asteroid, while others went extinct 2 to 3 million years after the impact, in the beginning stages of climate change.

Fastovsky said the study would be difficult to apply to another mass extinction, because the precise fossil record at Petrified National Park is such a rare phenomenon.

“Other extinctions could potentially be studied in a similar way, but logistically it’s a tall mountain to climb,” Fastovsky said. “It’s possible there could be other ways to get at it, but it’s very time consuming and difficult.”