Reservoir-Corrected Musselshell Dates for the Cascade Phase on the Lower Snake River

Summary

This is an abstract from the "The Second-Oldest Sites in the Pacific Northwest" session, at the 88th annual meeting of the Society for American Archaeology.

Freshwater mussel shell is common at alluvial sites on the Columbia Plateau, and often used for radiocarbon dating of early and mid-Holocene sedimentary deposits of archaeological or geological interest. Paired radiocarbon ages on freshwater mussel shell and charcoal have shown acceptable agreement at sites on the middle and lower Salmon River in Idaho, and at Marmes Rockshelter on the Palouse River in southeastern Washington. However, confronted with their lack of agreement along the middle and lower Snake River, archaeologists have variously acknowledged, passed over without comment, or offered corrections incorporating shell samples derived from outside the Snake River hydrological basin. This paper examines paired shell/charcoal ages for mid- and early Holocene sites along the lower Snake River, focusing on the Cascade phase of the Leonhardy and Rice cultural sequence. Since the 1960s this taxon has been plagued by chronological ambiguity, with age ranges estimated at between 8000 and 4500 RCYBP. However, when the mussel shell dates are revised using reservoir-corrected regression equations based on paired samples restricted to the Snake River basin, results suggest that the Cascade phase as originally defined is mid-Holocene and post-Mazama rather than early Holocene and pre-Mazama in age.

This Resource is Part of the Following Collections

• The Second-Oldest Sites in the Pacific Northwest   •
• Society for American Archaeology 88th Annual Meeting, Portland, OR (2023)

Keywords

Record Identifiers

Abstract Id(s): 36309.0