Holy Dancing Dinosaurs!

'Dino Dance Floor' Found In Ariz.
Site Has 1,000+ Dinosaur Tracks, Professor Says



PAGE, Ariz. -- University of Utah geologists said they have discovered prehistoric animal tracks on the Arizona-Utah border so densely packed they're calling it a "dinosaur dance floor."

The three-quarter-acre site is in Arizona in the Coyote Buttes North area of the Paria Canyon-Vermilion Cliffs Wilderness.

Estimated to be 190 million years old, the site has more than 1,000 and perhaps thousands of dinosaur tracks, averaging a dozen per square yard in places, said Marjorie Chan, professor and chair of geology and geophysics at the University of Utah.

The site is so dense with dinosaur tracks that geologists said it reminds them of a popular arcade game in which participants dance on illuminated, moving footprints.

"It was a place that attracted a crowd, kind of like a dance floor," Chan said.

A study identifying the dinosaur track site was published in the October issue of the international paleontology journal Palaios. Chan is senior author of the study, which was conducted for a master's degree thesis by former graduate student Winston Seiler.

The range of track shapes and sizes reveals at least four dinosaur species gathered at the watering hole, with the animals ranging from adults to youngsters, Seiler said.

"The different size tracks, 1 inch to 20 inches long, may tell us that we are seeing mothers walking around with babies," he said.

The new study is the first scientific publication to identify the impressions as dinosaur footprints on a trample surface, Chan said.

Numerous dinosaur track sites have been found in the western United States, including more than 60 in Navajo Sandstone, where actual dinosaur bones are rare.

"Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000," Seiler and Chan wrote. And they said the density of tracks is much greater than it is at even larger track sites, such as the one at Coral Pink Sand Dunes State Park in Utah.

The 2.4-inch-wide tail-drag marks, which are up to 24 feet long, are a special discovery because there are fewer than a dozen dinosaur tail-drag sites worldwide, Seiler said. Four tail drags were within the 10 plots he surveyed, and there are others nearby.

"Dinosaurs usually weren't walking around with their tails dragging," Seiler said.

Seiler said he first saw the site in 2006. "At first glance, they look like weathering pits -- a field of odd potholes," he said. "But within about five minutes of wandering around, I realized these were dinosaur footprints."

When the footprints were made 190 million years ago, "the continents were arranged so this area was in the tropics" and was part of the supercontinent named Pangaea, Seiler said. "It was a desert, like the Sahara but much larger than the Sahara is today, covering much of Utah, Wyoming, Colorado, New Mexico, Arizona and Nevada," he said.

Seiler said he envisions the dinosaurs were "happy to be at this place, having wandered up and down many a sand dune, exhausted from the heat and the blowing sand, relieved and happy to come to a place where there was water."

The trample surface "helps paint a picture of what it was like to live back then," he said. "Tracks tell us what the dinosaurs were doing, what their behavior was, what life was like for them, what they did on a day-to-day basis."

After the dinosaurs left their prints, the trample surface was covered by shifting dunes, which eventually became Navajo Sandstone. Then, the rock slowly eroded away, exposing the tracks. The tracks eventually will erode, too, Seiler said

Posted by GSL