Historic Discovery

Amanda Bednarick in the Petrified Forest

As an undergraduate, Amanda Bednarick ’19 was part of the field team working with Reilly Hayes on the discovery at Petrified Forest National Park, Arizona.

Reilly Hayes

A team of URI scientists, statisticians, and students has determined a mass extinction that occurred 215 million years ago was not the result of a catastrophic event such as an asteroid.

The team made this determination after conducting paleontological fieldwork in sediments 227 to 205 million years old in Petrified Forest National Park, Arizona. The journal Geology recently published their findings.

David Fastovsky, professor of geosciences, oversaw the fieldwork conducted by graduate student Reilly Hayes ’17, MS ’19, who led the study that focuses on the extinction of ancient Late Triassic vertebrates—the disappearance of which scientists call the Adamanian/Revueltian faunal turnover.

Fossil records viewed differently

“The team refined the resolving power of the Petrified Forest fossil record from a scale of millions to hundreds of thousands of years,” Hayes said. Hayes describes this as analogous to being able to examine the 20th century on a scale of years rather than decades.

Hayes spent about five months over the course of two summers conducting the fieldwork for the study. Undergraduates Amanda Bednarick ’19 and Catherine Tiley ’20 were also part of the field team.

“This opens the door to looking at fossil records in a different way.”
Reilly Hayes MS ’19

“This opens the door to looking at fossil records in a different way,” Hayes said. “Our statistical models tell us it is exceedingly unlikely that these animals were killed off by a sudden event.”

Hayes, who is now a Ph.D. student at U.C. Berkeley, California, said URI afforded him the opportunity to take into the field what he learned in the classroom. “Fastovsky’s classes were great,” he said, “because if you did signal an interest, he would take you down the rabbit hole.”

And into the annals of history.

Read more: URI researchers: Asteroid, sudden event not responsible for mass extinction 215 million years ago.