Washington, Oct 21 : Geologists from the University of Utah in the US have identified an amazing concentration of dinosaur footprints that they call "a dinosaur dance floor," located in a wilderness on the Arizona-Utah border where there was a sandy desert oasis 190 million years ago.
The three-quarter-acre site, which includes rare dinosaur tail-drag marks, provides more evidence that there were wet intervals during the Early Jurassic Period, when the US Southwest was covered with a field of sand dunes larger than the Sahara Desert.
Located within the Vermilion Cliffs National Monument, the "trampled surface" has more than 1,000 and perhaps thousands of dinosaur tracks, averaging a dozen per square yard in places.
The tracks once were thought to be potholes formed by erosion.
The site is so dense with dinosaur tracks that it reminds geologists of a popular arcade game in which participants dance on illuminated, moving footprints.
"Get out there and try stepping in their footsteps, and you feel like you are playing the game 'Dance Dance Revolution' that teenagers dance on," said Marjorie Chan, professor and chair of geology and geophysics at the University of Utah.
"This kind of reminded me of that - a dinosaur dance floor - because there are so many tracks and a variety of different tracks," she added.
"There must have been more than one kind of dinosaur there. It was a place that attracted a crowd, kind of like a dance floor," she further added.
According to University of Utah geologist Winston Seiler, the range of track shapes and sizes reveals that at least four dinosaur species gathered at the watering hole, with the animals ranging from adults to youngsters.
"The different size tracks (1 inch to 20 inches long) may tell us that we are seeing mothers walking around with babies," he said.
Chan said that the new study is the first scientific publication to identify the impressions as dinosaur footprints on a trample surface.
As part of the study, Seiler marked off 10 random plots, each of 4 square meters, or roughly 2 yards by 2 yards. He counted 473 tracks within those plots - an average of 12 per square meter.
He conservatively estimates that the 3,000-square-meter site (about 0.75 acres) has more than 1,000 tracks, but he and Chan believe there perhaps are thousands.
"Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000," according to Seiler and Chan.