Hikers can follow in the footsteps of dinosaurs that walked through Jurassic streams and rivers 155 to 165 million years ago.
More than 2500 dinosaur tracks have been found on the outer slopes of the Salt Valley Anticline, a deep depression that runs the length of Arches National Park.
Two dinosaur track sites are easy to access off Hwy 191 north of Moab: Copper Ridge Sauropod Tracksite and Willow Springs Road.
The Copper Ridge Sauropod Tracksite is 23 miles north of Moab. The site can be accessed by taking the North Klondike Bluff road off of Hwy 191. The two mile dirt road is well-maintained and can be used by a passenger car, however it should be avoided when wet.
The Copper Ridge Sauropod Tracksite was discovered in 1989 by paleontologist Linda Dale Jennings Lockley. The tracks are preserved in the Morrison Formation, a geologic layer that is one of the most famous for yielding Jurassic dinosaur bones and tracks.
The Copper Ridge tracksite is the first sauropod trackway reported in Utah.
Sauropods are large herbivorous dinosaurs with long tails and necks, small heads and thick legs. ReBecca Hunt Foster, the paleontologist at the Moab Bureau of Land Management office said that the sauropod at this site may have been an Apatosaurus, a large dinosaur that could be 75 feet long and weigh as much as four elephants.
There are approximately 13 round sauropod tracks that make a quick right turn going up the hill. Next to it are tracks of four carnivorous dinosaurs that left three-toed tracks.
The larger set of the three-toed tracks are believed to be from an Allosaurus, which looks like a smaller Tyrannosaurus Rex and averaged about 39 feet tall. It appears to have a limp as the a gait shows a long five foot stride alternating with a shorter four foot stride.
Finding tracks that make a sharp turn is unique.
“Most tracks go in a straight line,” Foster said. And while the combination of the herbivorous dinosaur and carnivorous together at one site suggests that sauropod was being hunted, Foster said there is no way to know whether the tracks were made on the same day.
“It’s a fun story, but there is no scientific proof,” Foster said. “The tracks could have been made the same day, or days apart.”
The tracks were originally laid in wet sand, near an oasis or within a small riverbed. The rock shows the ripple effect of water moving over the sand. Mud then covered the sand in a short period of time, perhaps within a few days. That encasing of mud that later turned to rock preserved the tracks for several millions of years.
Several three-toed tracks can also be seen in the Entrada rock near Willow Springs Road.
“Entrada preserves all sorts of tracks,” Foster said.
The Entrada formation is from 165 million years ago, which had a little dryer climate than when the Morrison formation was formed.
Willow Springs Road is well-marked, approximately 11 miles north of Moab on Hwy 191. It is a well-maintained dirt road that leads 2.5 miles to the Sovereign single track trailhead. The dinosaur tracks are 3.4 miles from Hwy 191, and one mile past the Sovereign trailhead. Four wheel drive is recommended for a stint of sand in a wash where the road crosses.
The road is also the original entrance into Arches National Park. High clearance and four-wheel drive is recommended to make the trek into the national park.
The three-toed tracks are from human-sized predators.
“Fran Barnes was very big on making sure that track site was protected,” Foster said. “He worked with the BLM to make sure that it was known and protected.”
Fran Barnes and his wife Terby authored and published several books through Canyon Country Publications, which documented and named many locations in the Moab-area. Barnes died in 2003.
Foster has started a local chapter of the Utah Friends of Paleontology. Forty people attended their first meeting at the library in February.
The second scheduled meeting is 6 p.m., Wednesday, March 27 at the library. State paleontologist Jim Kirkland will speak at that meeting.
“Everybody is welcome,” Foster said.
She hopes that as the chapter develops, members can go to sites and document the tracks “And keep an eye on the conditions,” she said. “It’s good for the locals to keep an eye on tracks.”
Foster said that it is illegal to make casts from the tracks.
“We like to remind people not to pour plaster or damage the tracks. It can ruin it. Just take pictures,” Foster said. “It is illegal to pour anything other than water into the tracks. Any replication of the tracks they would need a paleontology permit.”