Geologists doubt dinosaur dance floor

By Lana Groves, Asst. News Editor

A group of geologists are saying a cluster of rock holes in Southern Utah identified as dinosaur footprints by a U professor and graduate student are nothing more than eroded potholes.

When the area, which U researchers called a “dinosaur dance floor,” gained global attention last month, the Bureau of Land Management sent four geologists and paleontologists to investigate the supposed tracks.

“We were concerned they weren’t dinosaur tracks,” said Andrew Milner, a paleontologist for the St. George (Utah) Dinosaur Discovery Site at Johnson Farm. “We did see a lot of dinosaur tracks but not at the dance floor.”

Milner and three others reviewed the site in Vermilion Cliffs National Monument and concluded the tracks were unusually shaped potholes.

Winston Seiler, who graduated from the U last year, saw the three-quarter acre site when he was working on his doctoral thesis project about the geology of rocks in a Navajo Sandstone formation. Noting the unique shapes and large number of holes, he discussed the possibility the holes were dinosaur tracks with his advisor, Marjorie Chan.

Seiler and Chan determined the holes were dinosaur tracks, published their findings and shard their research with various paleontologists in Utah and at the U.

The paper included pictures of what they considered tracks, some of which bare cracks that look like claw marks.
“They are unusual,” said Alan Titus, a paleontologist for the BLM. “(But) only a handful looked like they had claws or toes, and the ones we examined that had unusual marks were caused by a fracture (in the rock).”

The BLM sent Titus, Milner, Geologist Rody Cox from the BLM and Brent Breithaupt, director and curator of the University of Wyoming’s Geological Museum, to investigate whether the holes were dinosaur tracks, but also because the site is in a restricted section of the National Monument that can take up to two years to open for public access.

The Wave, a collection of Navajo Sandstone formations where the tracks were found, sits just over the Arizona border from Utah. Titus said tourists are already calling about the site and the BLM needed to know if the site was legitimate.

The team surveyed the area and concluded the unusual imprints were potholes caused by erosion.
“Most of the holes are perfectly circular or elliptical. You just don’t see dinosaurs with dinner-plate shaped feet,” Titus said.

Chan, chairwoman of the U’s Department of Geology and Geophysics and an expert on eroded potholes, said she saw the site a couple years before Seiler approached her with the idea that they were dinosaur tracks and thought the holes were different than most potholes.

“It’s unusual to get a high concentration of pot holes,” Chan said. “My first impression was these were pot holes, but there was something wrong here. They didn’t look like the typical ones.”

Along with two members of the investigative team, Chan will return to the site next spring to examine the holes and look for signs as to what may have caused some of the holes to resemble dinosaur tracks.

Milner said if the rock has more calcium carbonate than usual, the holes could have eroded in non-circular patterns.
Despite how unusual the holes appear, Titus said Chan and Seiler should have brought experts out to investigate the site before publishing a paper.

“We’re not trying to bash Dr. Chan or Winston Seiler,” Titus said. “They’re looking forward to a collaboration to finally resolve this, and maybe even publish a research paper on how to distinguish between tracks and potholes.”

When leaving the dance floor, Titus said the team came across a few smaller groupings of actual dinosaur tracks near the “dance floor.”

“These are genuine track sites that occur in the vicinity of the Wave,” he said. “We can give (the public) coordinates for that.”

Even though the site might not have been caused by dinosaurs, Chan said she is excited to go back to learn more about the rock holes

“I’m looking for some of the positive things that will come out of it,” she said. “There’s a lot of great dinosaur track sites coming out of (that area).”

University of Utah

U researchers have discovered a large number of dinosaur tracks in the Navajo sandstone formation. The tracks are a further proof that there were ponds of water in the area during the Jurassic period.