rimrockdraw1.jpg

An archaeological team excavates the Rimrock Draw Rockshelter site in 2013. A stone tool has been found at the site that could be more than 15,800 years old.

(Patrick O'Grady/University of Oregon)

Update: Information has been added to this story about the date of the tool's discovery, ongoing analysis of the tool and plans for publication.

Update 2: NASA successfully fired Space Launch System booster rocket March 11. Check out a NASA video of the test on YouTube.

Hear that hammering? It might be the sound of another nail being driven into the coffin of archaeology's "Clovis first" theory.

The theory holds that the oldest cultural tradition in the Americas is that of a prehistoric culture identified from distinct stone tools found near Clovis, New Mexico, in the early 20th century.

However, in the past couple of decades, work at sites such as Monte Verde, Chile, and Oregon's own Paisley Caves has uncovered evidence of human occupation in the Americas that predates the Clovis culture. (While still preliminary and not yet peer-reviewed, some evidence from an archaeological site in Vero Beach, Fla., may suggest humans were present there at least 14,000 years ago.)

Like Paisley Caves, the potential new nail in "Clovis first" comes from the work of archaeology teams from the University of Oregon.

The UO and federal Bureau of Land Management say teams recently uncovered a small stone tool made of orange agate at Rimrock Draw Rockshelter in southeastern Oregon.

This orange agate tool was found in 2012 at the Rimrock Draw Rockshelter archaeological site in southeastern Oregon. Ongoing analysis recently found blood residue on the tool consistent with bison. It's also been preliminarily dated as being older than 15,800 years old based on its relationship to an ash layer of that age. Archaeologists plan to return to the Rimrock site this summer to collect more data and subsequently publish information about the tool and that site.

The tool actually was found in 2012 beneath an undisturbed layer of ash from a Mount St. Helens eruption dating to 15,800 years ago. The artifact's position beneath the undisturbed layer would suggest it is older than that date, making it older than the oldest and best-dated Clovis artifacts, which are 13,500 years old.

Patrick O'Grady, director of excavations at Rimrock and a staff archaeologist with the UO Museum of Natural and Cultural History, said that would suggest the Rimrock tool could be evidence of "the oldest human occupation west of the Rockies." However, more evidence needs to be collected at Rimrock before the discussion can continue as to how it relates to the realm of pre-Clovis sites, he said.

Last week (ending March 7), blood residue analysis was performed on the tool, yielding a match for proteins consistent with bison, probably an extinct species called Bison antiquus, UO staff said.

O'Grady said his team has reported on the tool and other aspects of the Rimrock site at various archaeological conferences since its discovery. However, analysis of the tool won't be published until after UO's archaeological field schools this summer (June 22 to July 31), when UO archaeologists plan to return to Rimrock to gather more data about the Mount St. Helens ash layer. Besides Rimrock, archaeologists will conduct a field school at another Oregon site called Connely Caves.

As such, time, more evidence and peer review will tell whether this and other Rimrock artifacts hold up to their promise of a challenge to Clovis first theory.

In other science news ...

Switching now from stone tool technology to tech of a more modern sort, NASA is scheduled to do its first ground test firing of the most powerful solid rocket booster ever built, the Space Launch System, at 8:30 a.m. PDT Wednesday, March 11, at a test facility in Promontory, Utah. Wednesday's two-minute static test will be one of two ground tests necessary to qualify the booster for flight. Once qualified, it will be ready for use in test flights of NASA's Orion spacecraft, which eventually will carry astronauts into space.

The SLS is a heavy-lift rocket aimed at propelling future deep-space missions, such as manned expeditions to Mars. The SLS successfully completed a hot fire test in January at Stennis Space Center in Mississippi.

NASA TV plans to air the ground test live on Wednesday, as well as events from a NASA Social dedicated to the SLS the day before.

-- Susannah L. Bodman, sbodman@oregonian.com, www.facebook.com/Sciwhat.Science, Twitter: @Sciwhat