By Wynne Parry, LiveScience Senior Writer | LiveScience.com – Thu, Jul 12, 2012
Ancient stone projectile points discovered in a Central Oregon cave complex have cast new light on the identity of the first Americans.
These are generally believed to be younger than Clovis points. However, researchers have had difficulty finding materials that can be reliably dated at the Western Stemmed point sites, Jenkins said during a press conference yesterday (July 11).
Archaeologists often look at the decay of radioactive carbon atoms within organic material to determine its age. In Oregon's Paisley Caves, where the four new Western stemmed points showed up, the researchers found some of the ancient organic material they needed, most notably, in coprolites, or dried feces, carrying human DNA.
The coprolites appeared to have been left behind at about the same time as the nearby projectile points.
Radiocarbon dating put the coprolites and other organic samples located near the points at more than 13,000 years old. The team examined the sedimentary layers and the artifacts to determine if the sediment, and as a result the timeline preserved as new layers are laid down, had been disrupted or if the samples had been contaminated.
As a result, they determined that the projectile points — which were broken and appear to have been cast aside as garbage — were as old or older than Clovis points found elsewhere.