EXPANDING THE GEOARCHAEOLOGICAL FRAMEWORK OF THE COOPER'S FERRY SITE (10IH73), IN WESTERN IDAHO

The Cooper’s Ferry site, located in the lower Salmon River canyon of western Idaho, may contain the earliest evidence of humans in the Pacific Northwest in a buried, stratified context. In the 1960s, archaeological excavations adjacent to an eroding bank produced a lithic assemblage of stemmed projectile points associated with the Western Stemmed Tradition. Unfortunately, no chronometric ages were obtained during these excavations and stratigraphic profiles were not described in an easily discernible format. Recent excavations have yielded radiocarbon ages spanning from 12,000 yr B.P. to 7,300 yr B.P. Using archival information and magnetometry, we located and excavated the early trench to expose the previously documented profile. By locating, unearthing, and recording the stratigraphy, we correlated past excavations with current units through a combination of traditional geoarchaeological methodologies and modern analytical techniques (i.e., lithostratigraphy, pedostratigraphy, chronostratigraphy, and chemostratigraphy). This updated approach provides a better understanding of the archaeological site formation processes within the canyon and provides a more resolute chronological context for the early stemmed point assemblage discovered in the 1960s. Furthermore, it provides a framework for further early site discovery within the canyon and provides a model for other site reinvestigations.