Researchers found an ancient agate tool in Oregon that is believed to provide evidence of one of the oldest-known human occupations in the Western United States.
The fascinating artifact was discovered in the Rimrock Draw Rockshelter, which has been under excavation since 2011, the Bureau of Land Management reported. It was uncovered beneath a layer of ash from an eruption of Mt. St. Helens that occurred about 15,800 years ago.
The tool is believed to have been used for scraping animal hides, butchering meat, or even carving wood. A blood residue analysis revealed animal proteins believed to be from an ancient species of bison that is related to the modern buffalo.
"The discovery of this tool below a layer of undisturbed ash that dates to 15,800 years old means that this tool is likely more than 15,800 years old, which would suggest the oldest human occupation west of the Rockies," said Scott Thomas, BLM Burns District archaeologist.
Researchers had already suspected ancient humans had resided around the excavation site because in 2008 a team of archaeologists discovered 14,000-year-old feces containing human DNA in the nearby Paisley Cave.The discovery of this ancient tool pushed the existence of humans in Oregon back even further.
"When we had the volcanic ash identified, we were stunned because that would make this stone tool one of the oldest artifacts in North America. Given those circumstances and the laws of stratigraphy, this object should be older than the ash," said Patrick O'Grady, with the University of Oregon Archaeological Field School.
In the future, the researchers plan to expand their excavations in hopes of finding even more evidence of the existence of these ancient humans. Archaeologists have also found tooth enamel fragments believed to have belonged to a prehistoric camel and stone projectile points at the site.
"For years, many in the archaeological field assumed that the first humans in the western hemisphere were the Clovis people - dating to around 13,000 years ago. While a handful of archaeological sites older than Clovis cultures have been discovered in the past few decades, there is still considerable scrutiny of any finding that appears older," McDonald said. "With the recent findings at Rimrock Draw Shelter, we want to assemble indisputable evidence because these claims will be scrutinized by researchers. That said, the early discoveries are tantalizing."
