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01-24-06
By Mark Floyd, 541-737-0788
Source: Roberta "Bobbi" Hall, 541-737-4515, rhall@oregonstate.edu
CORVALLIS, Ore. - Researchers from Oregon State University have analyzed a second archaeological site on the southern Oregon coast that appears to be about 10,000 years old, and they are hopeful that their newly fine-tuned methodology will lead to the discovery of more and older sites.
Results of their study were just published in the journal Radiocarbon.
The site, located on a bluff just south of Bandon, Ore., included a large number of stone flakes, charcoal pieces and fire-cracked rock, according to Roberta Hall, professor emeritus of anthropology at OSU and principal investigator in the study. There also is evidence of a stone hearth, Hall added.
"There are a lot of rock outcrops nearby that would make good sources for tools," she said, "and it appears that tool-making is one of the activities the site may have been used for. We only dug two pits, each two meters long by a meter wide, so there is potential to find much more there."
Funded by Oregon Sea Grant, the project builds on a 2002 study when the OSU researchers analyzed a site in Boardman State Park north of Brookings, Ore., which eventually was dated at nearly 12,000 years old, making it the oldest coastal archaeological site in Oregon. Both sites are unusual, not only because of their age but in how they were discovered, Hall said.
The OSU research team - which included anthropologist Hall, geoarchaeologist and field work supervisor Loren Davis, graduate student Samuel Willis, and soil scientist Matthew Fillmore - developed a model using geologic features, soil type and radiocarbon dating to pinpoint locations most likely to include the oldest sediments. Their theory: these older sediments hold the greatest potential for holding late Pleistocene (older than about 11,000 years) or early Holocene sites.
The discovery of a second ancient site in this manner validates their methods, the scientists say.
Most archaeological sites are unveiled by the discovery of early signs of human activity - the finding of a projectile point or stone flakes. But the Oregon coast is a notoriously difficult place to conduct archaeological research because of the weather, changing sea levels, and tumultuous geologic events, including earthquakes and tsunamis.
Humans may have come to Oregon earlier than 12,000 years ago, the researchers say, but finding evidence of their habitation is agonizingly difficult.
"At that time, the ocean was much lower and the shoreline was a few kilometers west," Hall said, "meaning that any site that was on the coast during the late Pleistocene is now under water."
Rarely do the sites include any bones or other organic matter, she pointed out. The combination of wet weather and highly acidic soil hastens decomposition. However, sites that contain a lot of mollusk shells - particularly clams, mussels and barnacles - will often include bones because the shells lower the acidity of the soil, slowing decomposition.
But the farther away sites are from where the old coastline lay, the less likely researchers are to find mollusk shells.
"It can be quite frustrating," Hall said. "Likewise, the river valleys are difficult to excavate because they either have so much alluvium on top you'd need to dig down the equivalent of a three-story building, or all the material has been washed away in floods."
The Bandon-area site was excavated down to 235 centimeters - which is considered very deep - and the OSU researchers discovered charcoal in all but the uppermost levels. Artifacts, primarily stone flakes, were found as deep as 215 centimeters, which corresponds to a date of just over 10,000 years old. More sophisticated stone tools were found at a shallower depth and obviously were younger.
Findings of charcoal and fire-cracked rock were abundant.
Absent from the site was evidence of much obsidian, which was plentiful at the Indian Sands site near Brookings, though it was not local in origin. Indian Sands, however, is closer to potential sources of obsidian, including the Klamath area and northern California.
"The Bandon site is important not so much for what we found," Hall said, "but in how we found it. And it adds to our knowledge about coastal habitation in general."
Hall said the OSU research team hopes to secure additional funding to look for other ancient sites along the Oregon coast.
"We know they're out there," she said. "And now we know better how to find them."
About the OSU College of Liberal Arts: The College of Liberal Arts includes the fine and performing arts, humanities and social sciences, making it one of the largest and most diverse colleges at OSU. The college's research and instructional faculty members contribute to the education of all university students and provide national and international leadership, creativity and scholarship in their academic disciplines.