Professor, alumnus aid dinosaur tracks discovery

For several years, associate professor Erik Kvale and Al Archer, an IU alumnus and associate professor of geology at Kansas State University, have been working on dinosaur track sites from the Middle Jurassic period.\nTheir findings were presented Nov. 16 at the annual convention of the Geological Society of America in Reno, Nev.\nKvale, his family and Archer found vast dinosaur track-bearing deposits in May 1997 at the Bighorn Basin in northern Wyoming, which dated back to the Middle Jurassic period. \nDiscoveries of tracks and fossils from the period, which lasted from 159 to 187 million years ago, had been limited in North America to Utah until recently. As a result, fairly little is known about dinosaurs from this era, Kvale said. \n"The tracks were found in the Sundance formation, a 167 million-year-old rock unit composed of rocks that were originally sediments in a shallow ocean that existed in northern Wyoming during this period," he said. "The sea-level fluctuated during this time and -- contrary to what was originally believed -- northern Wyoming was not submerged in water, periodically it was a beach." \nA new discovery in the Bighorn Basin, specifically in the Gypsum Spring formation, was found during April 1999. Walter Parrs Jr., a New York City resident, was visiting "The Hideout," a western guest ranch in the Bighorn Basin of northern Wyoming, when he stumbled on the most extensive Middle Jurassic dinosaur tracksites in North America, Kvale said. \nScientists then verified Parrs' discovery and were able to identify other sites, said Gary D. Johnson, a Dartmouth College professor involved in the Gypsum Spring tracksite. \n"These tracks, found in the Gypsum Spring formation, intermittently cover a 2000-square-kilometer area and are three million years older than the tracks found at the Sundance formation," Kvale said.\nWhat kept these tracks preserved was organic material that once covered the flat beach-like area inhabited by the dinosaurs. The organic material, made up of algae or bacteria, was very sticky and formed an organic "glue" that held grains of sand and mud together, Kvale said. When the dinosaurs would walk across the area, the organic material "glued" the grains within the tracks together and preserved them, Kvale said. \nAs it builds up, this kind of organic material also develops into rock formations.\n"Rock formations, such as the Sundance and Gypsum Spring formations, are produced when sediments, such as sand and mud, are laid down in different environments and eventually lithified to form a rock unit," said Brent Breithaupt, director of the University of Wyoming Geological Museum and who also worked at the sites. \nNow on the flat area where the dinosaurs walked are the Sundance and Gypsum Spring formations. The finding of the tracks helps scientists know more about the terrain of the area and the distribution of dinosaurs in North America, Breithaupt said.\n"Similar to the Sundance formation, tracks were found at the Gypsum Spring formation made by land-dwelling two-legged dinosaurs, some of which were made by theropods (carnivorous dinosaurs)," Kvale said. "Although it is not unusual to find theropod tracks, what is unusual is the quantity of tracks found. The only other site in North America that is an approximate age equivalent to the Gypsum Spring and Sundance sites is in Utah, and they only have a few dozen tracks preserved. We have thousands to hundreds of thousands preserved."\nAnother exciting find at the Gypsum Spring site was that the tracks preserved have toe and heel impressions, whereas tracks found at the Sundance site showed only the three toes and rarely the heel of the dinosaur's foot, Kvale said. \n"Comparable discoveries of many dinosaur tracks in younger rocks in Utah have resulted in large areas being established as national or state parks and monuments," he said.\nAs an example, he cited the establishment of the Red Gulch Dinosaur Tracksite, which is a 40-acre area being developed as a dinosaur educational site accessible to the public as a result of the discovery at the Sundance formation.\n"We now have direct evidence that dinosaurs existed in northern Wyoming during this time," Kvale said. "Our discovery is sure to prompt other researchers to look in age-equivalent rocks elsewhere in the Rocky Mountain region for other trackways"