SALT LAKE CITY — Life-sized figures sketched into red rock cliffs in Canyonlands National Park were drawn 1,000 years more recently than what had long been believed, a team of Utah State University scientists discovered about the world-renowned rock art.
The team used modern luminescence dating techniques to analyze when the art went up in what is known as the "Great Gallery" in southeastern Utah's Horseshoe Canyon. The researchers believe the figures were created 1,000 to 2,000 years ago instead of the previously thought 2,000 to 4,000 years ago.
The study suggests the drawings may been done as man transitioned to a culture of farming and away from hunting and gathering, said David Whitley, one of the foremost experts on rock art in North America.
The research becomes important in better understanding art known as Ancient Barrier Canyon-style paintings, which are usually shrouded in mystery, said Whitley, who was not involved in the study.
Because of the more recent time stamp, the art was likely created during a time of great transition, when new ideologies, religions and customs were emerging, said Steven Simms, a Utah State University anthropology professor, who worked with university geology professor Joel Pederson on the study.
"It puts in a very momentous time," Simms said.
They published a paper of their findings this month in the online Early Edition of the Proceedings of the National Academy of Sciences.
Determining the date of rock art is very difficult, and there has traditionally been very little interest from scientists in tackling the projects, said Whitely, who has studied rock art for 35 years and written 17 books.
"We tend to think of art and science as being polar opposites. The result is that artists don't talk about science much, and scientists don't talk about art much," Whitley said. "I'm very happy they did this."
The seeds of the study were planted about eight years ago when a man brought a piece of sandstone from the area to Pederson. The retired scientist and rock-art enthusiast wanted to find out if it were possible to assess the date of a drawing by looking at the composition or color of the rocks.
The question piqued the interest of Pederson, who specializes in the history of rivers and has written articles on the age of the Grand Canyon. After going to see the Horseshoe Canyon figures up close, Pederson was determined to test the man's theory.
"I realized, we can actually figure out the date of this," Pederson said. "It was just kind of luck that a rock-art enthusiast knocked on my door."
About a year later, he began work on the project that would take seven years to complete on a shoestring budget.
Luminescence dating techniques have been around for decades, but the method for the study is a newer form and was used with the help of scientists from Denmark, Pederson said.
They homed in on a date estimate by studying how sunlight bleached away stored signals of radiation on the exposed rocks, he said.
Pederson and Simms are hopeful they can study other rock art to determine more precise date estimates, saying they believe the technique is widely applicable.