Geochemical Characterization and "Sourcing" of the Beezley Chalcedony, Roza Member, Columbia River Basalt Group, Washington



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The Beezley Chalcedony is a high-quality chert source that occurs in the Beezley Hills, northern Grant County, Washington. Archaeological collections from sites in and near Grant County are visually similar to the Beezley Chalcedony. This study aims to geochemically characterize the chalcedony source locales material as a context for future comparisons with the Clovis tools. The Beezley Chalcedony formed from Middle Miocene diatomite-rich lacustrine sediments of the Squaw Creek Member of the Ellensburg Formation that is situated between the older Frenchman Springs Member and the Roza Member of the Wanapum Basalt Formation, Columbia River Basalt Group. Laser ablation ICPMS trace element analyses of chalcedony from seven site locations in the Beezley Hills and one in the nearby Quincy Potholes area reveal significant trace element variation for several elements (e.g., Ge, U, V, Y, and Zr). Five locations in the Beezley Hills display marked spatial variation in trace element concentrations and element ratios. The variations in trace element concentrations may be inherited from the source diatomite and minor shale units in the Squaw Creek Member or are related to element mobility during diagenesis. These trace element variations can be used as tools for linking the artifacts to source locations and for tracking artifact trade routes.



Chalcedony, Chert, Artifact, Silica, Sourcing, CRBG