Arkansas dinosaur tracks
The discovery of a large field of dinosaur tracks in Arkansas has researchers busy using cutting-edge technology and traditional techniques to learn all that they can about the animals and environment that existed there 120 million years ago.

The track site, found in southwest Arkansas, covers an area of about two football fields and contains the fossilized tracks of several species and tracks from multiple animals of the same species, some of which have never been previously documented in Arkansas. The site will help researchers learn not only about the creatures that once roamed through the area, but also about the climate during the Early Cretaceous period 115 to 120 million years ago.

"The quality of the tracks and the length of the trackways make this an important site," said Stephen K. Boss, who led the National Science Foundation-funded project. Based on the rock in which the footprints were found, researchers have a good idea of what the climate would have been like.

"Picture an environment much like that of the shores of the Persian Gulf today. The air temperature was hot. The water was shallow and very salty," Boss said. "It was a harsh environment. We're not sure what the animals were doing here, but clearly they were here in some abundance."

The most dramatic tracks found, those of a three-toed dinosaur, measure about two feet long by a foot wide. The researchers believe the footprints might belong to Acrocanthosaurus atokensis, one of the largest predators ever to walk the earth. The site also contains the giant prints of sauropods, large, long-necked plant-eating dinosaurs such as Pleurocoelus and Paluxysaurus. Other prints pepper the site as well, but it will take scientists some time to determine what other creatures might have walked through that area.

Thanks to a fast-track grant from the National Science Foundation, the University of Arkansas office of research and economic development and the J. William Fulbright College of Arts and Sciences, a team of researchers spent two weeks studying the site, which is on private property. In addition to chisels, hand-held brooms and plaster, some scientists brought along their computers. Jackson Cothren and Malcolm Williamson, researchers from the department of geosciences and the Center for Advanced Spatial Technologies at the university, documented the tracks using LiDAR, short for "light detection and ranging."

Visit the University of Arkansas website to see more photos of the dig.