313 Million-Year Old Fossilized Footprints Discovered In Grand Canyon Nation Park

GRAND CANYON NATIONAL PARK, Ariz. – Officials at Grand Canyon National Park announced Thursday that researchers have confirmed that some tracks found in a boulder in 2006 are fossilized footprints from 313 million years ago.

Hikers found the fossils as they came across a boulder lying next to their spot on the Bright Angel Trail. The hikers were college students being led by their Norwegian geology professor Allan Krill, according to a news release.

Krill sent a photo to his colleague, Stephen Rowland, a paleontologist at the University of Nevada Las Vegas.

Turns out the footprints were even more significant than Krill suspected when he first saw them on the trail.

“These are by far the oldest vertebrate tracks in Grand Canyon, which is known for its abundant fossil tracks,” said Rowland. “They are among the oldest tracks on Earth of shelled-egg-laying animals, such as reptiles, and the earliest evidence of vertebrate animals walking in sand dunes.”

The boulder fell off a cliff-exposure on the Manakacha Formation. The news release said using detailed geologic maps of the Bright Angel Trail along with comparisons to other studies of the formation, researchers determined the tracks to be 313 million years old, give or take 500,000 years.

The release described the tracks as a record of two separate animals on the slope of a sand dune. A reconstruction of the animal’s footsteps revealed what researchers called a “lateral-sequence walk.”

“Living species of tetrapods, dogs and cats, for example, routinely use a lateral-sequence gait when they walk slowly,” said Rowland. “The Bright Angel Trail tracks document the use of this gait very early in the history of vertebrate animals. We previously had no information about that.”

The release said these are the oldest recorded tracks of their kind found at the park.

The complete article with illustrations can be found at the PLOS ONE website.