An Ageless State of Mind


USU Rock Art Study Evokes Questions …
And that’s great news for archaeology

By Jerry D. Spangler

Our recent posting on findings by Utah State University researchers into the potential age of Barrier Canyon rock art – that at least some of the images might be much more recent than traditionally assumed – provoked some rather pointed criticisms questioning my own intelligence (or lack thereof) for giving any credence whatsoever to the research.

There were also many doubts expressed towards lead researcher, geologist Joel Pederson, and archaeologist and co-author Steven Simms, who was quoted widely in the news media.

To clarify, our re-posting of the research, published in the Proceedings of the National Academy of Sciences, was never intended to suggest that Pederson and Simms had resolved once and for all the question of the antiquity of Barrier Canyon rock art.

And I am fairly confident that Pederson, Simms, et al. would never argue that the question has been answered conclusively and definitively.

Why? Because they are serious scientists with impressive bona fides, and the fundamental nature of scientific inquiry is such that there is never really any certainty, only more questions for further inquiry. As the economist Thorstein Veblen astutely observed generations ago, “The outcome of any serious research can only be to make two questions grow where only one grew before.”

And in that regard, Pederson, Simms and the others who contributed to the research should be applauded. Not only did they challenge a long-held truism using sound scientific methods, but their research fosters the growth of many more questions worthy of future inquiry.

In summary, the Barrier Canyon rock art style has traditionally been assigned to Archaic hunters and gatherers who occupied the remote canyons of southern and eastern Utah. Some students of the style believe it is among the earliest artistic expressions in the American West, dating to at least 7,000 years ago. Many others assign a more conservative age range of 1700 B.C. to A.D. 300, based on the association of the images with datable materials in alcoves and rock shelters where the images are located.

Most archaeologists would probably agree that it could be Archaic, but they are reticent to embrace any age range for the Barrier Canyon images because there is no certainty that any of the datable materials were in fact left behind at the same time the images were painted on the canyon walls.

And the rock art itself has resisted (so far) attempts at direct radiocarbon dating.

Pederson addressed the problem using optically stimulated luminescence, a non-destructive technique which does not measure the age of the images themselves but rather measures, in a very simplified nutshell, when certain types of stone were last exposed to sunlight (see

His samples, from the famed Horseshoe Canyon district of Canyonlands National Park, were found to date between 900 and 2000 years ago – much more recent than most had assumed.

Will the research stand up to future inquiry? No one knows. And that’s not the point.

Pederson and his colleagues identified a relevant question, they collected and analyzed data using scientifically sound methods, and they subjected their research to rigorous peer review. Future researchers can examine their techniques and conclusions (as with any good science, the methods used in the Pederson study can be replicated). Future researchers can and probably will use new, even-better techniques that could challenge the earlier findings. And that research will, in turn, lead to new questions for yet other researchers.

Philosopher Bertrand Russell once wrote, “In all affairs it’s a healthy thing now and then to hang a question mark on the things you have long taken for granted.”

And that is the most exciting outcome of Pederson’s research. It raises more and more questions while challenging the rigid orthodoxy of assumption.

Jerry D. Spangler is executive director of the Colorado Plateau Archaeological Alliance, an organization dedicated to the protection and preservation of cultural resources on public lands. He can be reached at