Geologists discover 'dinosaur dancefloor' in remote American wilderness
An amazing array of footprints made by more than 1,000 dinosaurs have been uncovered on the Arizona-Utah border in the U.S.
Scientists have likened the wealth of tracks and tail-drag marks on the three-quarter acre site to a crowded 'dinosaur dance floor.'
Geologist Winston Seiler with some of the dinosaur tracks he identified for his thesis as a University of Utah master's degree student. The tracks were made some 190 million years ago
They believe the remote dry wilderness was once a sandy desert oasis 190 million years ago. It was then in the tropics as part of the supercontinent Pangaea.
'We're looking at an area much like the Sahara Desert with blowing sand dunes,' geologist Winston Seiler reported in the international paleontology journal palaios
'Areas between these sand dunes could have had ponds - oases.'
This would explain the sheer number of tracks as the exhausted thirsty giants traveled to the watering hole.
'Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000,' lead researcher Professor Marjorie Chan from Utah University said.
'It was a place that attracted a crowd, kind of like a dance floor.'
Tracks from sauropodomorphs - dinosaurs who walk on four legs - were found at the site
The range of tracks suggest at least four dinosaur species ranging from youngsters to adults visited the site.
'The different size tracks (from one to 20 inches long) may tell us that we are seeing mothers walking around with babies,' Seiler said.
He marked off 10 random plots of two square yards and counted 473 tracks - an average of 12 per square yard. His conservatively estimates the site has more than 1,000 tracks, but he and Chan believe there could be thousands.
They also discovered 2.4inch-wide tail-drag marks up to 24 feet long, which are particularly rare. There are fewer than a dozen such sites worldwide.
Geologists believe these markings show dinosaur footprints and tail-drag marks. Dinosaur footprints are named by their shape because the species and genus of animal that made them isn't known
When the site was first visited in 2005, Professor Chan originally thought they were strange potholes caused by erosion. However, on closer examination she discovered dinosaur features such as obvious claw, toe and heel marks.
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 will eventually erode too,' Seiler said.
(L) A 14-inch-long Sauropodomorph dinosaur track is two footprints in one. It was left by the front and back foot of a dinosaur that walked on four legs
(R) Scientists believe this 4-inch long Grallator dinosaur track was made by a tiny dinosaur only 3ft tall.
And as for the onewho fears standing in front of His Lord and restrainsthe soul from impure evil desires and lusts, verily, Paradise will be his abode [79:40-41]
Re: Geologists discover 'dinosaur dancefloor' in remote American wilderness
Huge Field of Dinosaur Tracks Found
20 October 2008
More than 1,000 dinosaur footprints along with tail-drag marks have been discovered along the Arizona-Utah border. The incredibly rare concentration of beastly tracks likely belonged to at least four different species of dinosaurs, ranging from youngsters to adults.
The tracks range in length from 1 to 20 inches (2.5 to 51 centimeters).
"The different size tracks may tell us that we are seeing mothers walking around with babies," said researcher Winston Seiler, a geologist at the University of Utah.
The tracks were laid about 190 million years ago in what is now the Vermilion Cliffs National Monument.
"There must have been more than one kind of dinosaur there," said researcher Marjorie Chan, professor and chair of geology and geophysics at the University of Utah. "It was a place that attracted a crowd, kind of like a dance floor."
While the site is covered in sand dunes now, the researchers say the tracks are within what was a network of wet, low watering holes between the dunes. In fact, the tracks provide more evidence of wet intervals during the Early Jurassic Period, when the U.S. Southwest was covered with a field of sand dunes larger than the Sahara Desert.
Chan and her colleagues, including Seiler, described the dinosaur track site in the October issue of the international paleontology journal Palaios.
By studying the shapes and sizes of the tracks, Seiler suggests four dinosaur species gathered at the watering hole, though the researchers have yet to match the prints with specific species. Currently, the tracks are named for their particular shapes and include:
Eubrontes footprints measure 10 to 16 inches (25 to 41 cm) long and have three toes and a heel. These tracks likely were made by upright-walking dinosaurs with a body length of 16 to 20 feet (5 to 6 m), or smaller than Tyrannosaurus rex.
Grallator tracks are about 4 to 7 inches (10 to 18 cm) long, are three-toed and were left by small dinosaurs only a few feet tall.
Sauropodomorph tracks, more circular than the other types, were left by creatures that walked on four legs and were the largest dinosaurs at the site. Their tracks range from 6 to 11 inches (15 to 28 cm) long. Seiler said the tail-drag marks are associated with these circular footprints, so they likely were made by sauropods.
Anchisauripus tracks measure 7 to 10 inches (18 to 25 cm) long and were made by dinosaurs that ranged from 6 to 13 feet (2 to 4 m) in length.
Numerous dinosaur track sites have been found in the western United States and elsewhere around the world. For instance, tracks from a herd of 11 giant sauropod dinosaurs were discovered in the ancient coastal mudflats of Yemen. But the new discovery is rare in the density of tracks.
"Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000," Seiler and Chan write.
Chan first visited the site of the dinosaur tracks in 2005 with a U.S. Bureau of Land Management ranger who was puzzled by them. Chan initially called them potholes, which are erosion features common in desert sandstone. "But I knew that wasn't the whole story because of the high concentration and because they weren't anywhere else nearby but along that one surface."
One unnamed reviewer of the Palaios study still believes the holes are erosion features, according to a statement released today by the University of Utah.
This Eubrontes dinosaur footprint, including three toes and a heel, measures roughly 16 inches (41 cm) long and is thought to have been made by an upright-walking meat-eater. (The inset outlines the footprint shape.) Credit: Winston Seiler.
In 2006, Seiler saw the tracks and had similar thoughts. "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."
And as for the onewho fears standing in front of His Lord and restrainsthe soul from impure evil desires and lusts, verily, Paradise will be his abode [79:40-41]
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