Rimrock Draw Rockshelter in Oregon, the United States, is one of the oldest human-occupation sites in North America.
Rimrock Draw Rockshelter is essentially a Paleoindian ‘open-air site,’ meaning that the early inhabitants took advantage of the protection offered by a shallow (ca. 3 m deep and 20 m long) overhang in an otherwise open landscape for protection from precipitation, wind, or the Sun, depending on the season.
A permanent stream was adjacent to the shelter during the earliest occupation of the site prior to 17,000 years ago and continuing to 9,000 years ago.
University of Oregon archaeologist Patrick O’Grady and colleagues have been excavating at this site since 2011 under an official partnership agreement with the Bureau of Land Management (BLM).
Discoveries at the site have included stone tools and tooth fragments from Pleistocene mammals, including bisons (Bison sp.) and camels (Camelops sp.).
“In 2012, we found camel teeth fragments under a layer of volcanic ash from an eruption of Mount St. Helens that was dated over 15,000 years ago,” the archaeologists said.
“We also uncovered two finely crafted orange agate scrapers, one in 2012 with preserved bison blood residue and another in 2015, buried deeper in the ash.”
“Natural layering of the rockshelter sediments suggests the scrapers are older than both the volcanic ash and camel teeth.”
“Several radiocarbon-dating analyses on the tooth enamel yielded exciting results: a date of 18,250 years before present.”
“That date, in association with stone tools, suggests that Rimrock Draw Rockshelter is one of the oldest human-occupation sites in North America.”
Additional testing of other camel and bison teeth fragments is currently underway, and the researchers are studying plant remains from cooking fires as well.
“The identification of 15,000-years-old volcanic ash was a shock, then 18,000-years old dates on the enamel, with stone tools and flakes below were even more…
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