Radiocarbon dating legacy collections: A Bayesian analysis of high-precision AMS 14C dates from the Par-Tee site, Oregon

Abstract

Archaeological materials in museum collections provide an excellent opportunity for researchers to investigate social, cultural, and environmental change. However, the precision of the archaeological analysis and interpretation is dependent on a firm understanding of the site chronology. The Par-Tee site (35CLT20), located on the northern Oregon Coast, produced a large archaeological collection including artifacts and faunal remains excavated in the 1960s and 1970s. Radiocarbon dates have been obtained on materials from the Par-Tee collections by several different researchers since the 1970s, but these data have not been adequately assessed for chronometric hygiene. To establish a reliable chronology for the Par-Tee site, we obtained new high-resolution accelerator mass spectrometry (AMS) radiocarbon dates and collagen peptide mass fingerprinting of cervid bones from throughout the site. We evaluate these new radiocarbon dates along with previous radiocarbon dates from the site, using chronometric hygiene assessments and Bayesian statistics to build a refined chronology for the Par-Tee site and museum collection. Previous research suggests site habitation occurred between 350 cal BC to cal AD 1150. Our reassessment of the site chronology suggests the primary site habitation occurred from cal AD ~100-800. We also identified evidence of subsequent site occupation around cal AD ~1490-1635 supporting previous interpretations of site habitation after the primary shell midden forming occupation. The latter occupation may be associated with a change in site use from a semi-sedentary village to a cemetery.

Learning to use atlatls: equipment scaling and enskilment on the Oregon Coast

“…Modelling of recently obtained radiocarbon dates on terrestrial mammal bone from the midden suggests that the primary period of occupation was around cal AD 100–800 (Sanchez et al . 2018). A few historic-era artefacts found near the site's surface indicate an additional, ephemeral period of reoccupation in the sixteenth and seventeenth centuries AD.…”

Humans, Dolphins, and Porpoises: Investigations at the Par-Tee Site, Seaside, Oregon, AD 100–800

“…from AD 100-800, likely with an intense occupation from AD 400-650 (Sanchez et al 2018). The small cetacean remains analyzed in this paper date to this ~700-year occupation.…”

“…A new Bayesian chronology for the site was established by Sanchez et al (2018) using dates obtained from cervid bones throughout the assemblage. The authors concluded that the main occupation of Par-Tee was over a span of ~700 years…”

“…The small cetacean remains analyzed in this paper date to this ~700-year occupation. There is also a later use of the site dated to ~AD 1490-1635 in which it seems the shell midden was used as a burial site; the human burials were shallow inhumations, interred in the shell midden after site abandonment (Arbolino et al 2005;Sanchez et al 2018).…”

“…A diachronic analysis of the small cetacean remains from Par-Tee is not possible at this time. Of the four units securely dated by Sanchez et al (2018), only two had intact stratigraphy. The sample size of small cetacean remains in these units is too small to lead to any meaningful interpretation.…”