The backcountry of Central-Eastern Oregon is surrounded by a sea of sagebrush from horizon to horizon. On these lands, managed by the Federal Bureau of Land Management, the winds are often screaming. On this morning in September, however, the winds are calm, except for a whisper blowing through the sage.
It's at this archaeological site that scientists have uncovered what may be the oldest evidence of man in North America, and perhaps in the Western Hemisphere...right here in Oregon.
Burns BLM archaeologist Scott Thomas takes the lead on a path to the ancient site. "Watch where you step," he warns. Rattlesnakes inhabit the area and become active as the sun warms the many rock outcrops. As luck would have it, none emerge.
Thomas is a veteran archaeologist who has worked in the Burns BLM district for 22 years. While the BLM manages millions of acres of public lands, it places a high priority on preserving evidence of ancient life—something increasingly found in the high desert of Central and Eastern Oregon. His job is to document and protect sites where evidence of human existence is found. He says this site—known as the Rimrock Draw Rock Shelter—is his most important discovery as a professional archaeologist.
A Big Discovery
Thomas discovered the site in 2009 while doing routine work. When passing a rock outcropping he had observed dozens of times, he finally stopped, walked in and investigated. He discovered obsidian used by natives to fashion tools and weapons, including a spear point. He also noticed sage eight feet tall. The soil beneath the sage was deep and black with carbon residue, indicating that life had existed there. There were signs of charcoal which indicated the use of fire. He speculated that whatever life there had been at the location was easily over 7,000 ago—but it turned out to be much older than he thought.
Soil and carbon 14 tests soon would reveal man's existence at the site 13,000 years ago. In the fall of 2012, archaeologists conducted a special excavation in an attempt the reach the bedrock. At the 10-foot level they found volcanic ash. Below that were remnants of camel teeth, and 10 inches below that, they uncovered a tool that may dramatically change the perceived time frame of the discovery.
An Ancient Multi-Tool
Thomas describes the tool the team found as a prehistoric 'Leatherman Tool' with multiple functions. There are two scraping edges which contained animal and blood residue, a sharp edge for cutting meat, and a point for drilling or punching holes into wood or leather. "It's a multi-tool like you would use out camping or hunting today," Thomas says.
The ash above where the tool was found was at first thought to be from Mt. Mazama, which erupted 7,600 years ago, forming Crater Lake. However, tests revealed that the ash was actually from one of many eruptions of Mt. St. Helens in Washington state, which occurred 15,800 years ago.
Subsequent tests will determine if the layering where the Mt. St. Helens ash was found corresponds to the time frame of the eruptions. If it does, and since the tool was found below the ash, a strong argument can be made that it's even older than the ash eruption. "If all the geological strata are in their natural and appropriate order, then that tool should be older than that ash," says Dr. Patrick O'Grady, who leads the University of Oregon archaeology team excavating the site.
Scott Thomas says, "It's possible that this tool is more than 16,000 years old. It could be one of the oldest artifacts in North America. In fact, it could be one of the oldest artifacts in the Western Hemisphere."
The tool is made from orange-colored agate, which is very hard and durable. Thomas says it's not clear where the agate originated since it's not found in the area where the tool was discovered. In this sage landscape, obsidian dominates. Because of that, researchers posit that the tool came from hundreds of miles away, giving rise to speculation about trade routes and migration.
"This is the oldest archaeology I've ever worked with," Thomas explains. "People were here much longer than we realized. Working on a site this old is the dream of a lifetime for me as an archaeologist."
In addition to the ancient scraping tool, the team has uncovered and dated a number of spearheads and other items. One object was a nearly perfect round ball made of pumice, resembling a large marble. Thomas speculates it was used in games.
Carbon Dating: Digging Deeper
Accuracy of carbon dating technology has seen many advances in the last 50 years. Initially the limit to testing for age was about 13,000 years, but advancements in dating have enabled archaeologists to reach deeper into ancient history. Approximately 100 miles southwest of the Rimrock site, the Paisley Caves discoveries—led by Dr. Dennis Jenkins at the University of Oregon—have determined human existence to date back 14,300 years. Discoveries in the eastern U.S. are ranging in the same time frame. Sites in South America are also being dated to around 14,000 years old—but Rimrock appears to be the oldest so far. Thomas says there are undoubtedly more sites to be found.
"Oregon has become the epicenter of ancient human discoveries in the West and perhaps North America," says Thomas. Recent research is also changing theories on how natives migrated and intermixed in North America. For years, it's been theorized that native societies migrated from Siberia to Alaska, then worked their way south into the Great Basin and populated the region.
Now, evidence from Oregon shows that societies have existed in the region for thousands of years. Each of them brought their own unique technologies in the making of tools and weapons. The Clovis society brought with them a method called "fluting" in their crafting of tools and weapons. "The Clovis met other people who used 'stemmed' points which were a different technology," says Thomas. "Many people are thinking that these two technologies met in this area—in Central Oregon and Northern Nevada—so much more attention is being placed in this area and research is reflecting that."
- Archaeologist Scott Thomas stands in front of the Rimrock Draw Rock Shelter, where he believes he's discovered some of the oldest evidence of man on the continent. Sandbags currently protect it from winter elements and erosion until the next excavation in summer of 2017. Photo by Brian Jennings.
Taken in context, while Oregon's archaeological research is finding evidence of ancient life dating back much farther than previously thought, the timeline found here—at least so far—pales in comparison to European discoveries which date back hundreds of thousands of years with research conducted on Cro Magnon and Neanderthal man.
Cro Magnon—now often called Anatomically Modern Humans, or AMH—are thought to have evolved as long as 195,000 years ago in Ethiopia. Neanderthals could have evolved as many as 200,000 years ago. The two groups co-existed for several thousand years. While Neanderthals died out, AMH did not. Some scientists believe that up to four percent of today's modern human population carries Neanderthal genes, sparking much controversial debate.
Still, the science is evolving. The dating of the Mt. St. Helens ash may provide a strong case that the Leatherman-like tool found near Burns may be much older than Thomas and his colleagues suggest. As word about the Rimrock discoveries spread, more researchers are getting interested.
Researchers from the Universities of Wyoming and Missouri, and Texas A&M University are expressing interest in the site and in potentially joining University of Oregon teams. Thomas says, "The cool thing about that is you get a lot of good minds working together on a puzzle, and you usually get better results."
Meanwhile, researchers continue to find more sites throughout Oregon. U of O's O'Grady says, "You never know what you are going to find or discover when you put your trowel or shovel to the ground."
As research and dating techniques evolve, it may be safe to say that, literally, they've only scratched the surface in Oregon.