Chemical Sourcing of Obsidian Lithic Fragments from the Grissom Site (45KT301) to Study Intra- and Inter-site Source Variability

The Grissom (45KT301) site, located in northeast Kittitas County, Washington, dates from 2500 B.P to the Historic period. While much of the assemblage remains unanalyzed, recent preliminary analysis revealed a high frequency of obsidian chipped stone artifacts. A technological, functional, and material analysis of 167 pieces of obsidian in addition to X-Ray Fluorescence (XRF) analysis of 51 pieces was undertaken in order to provide information on the number of obsidian sources represented, source frequencies through time, and the distribution of geochemical sources across the site. Nine unique sources were identified in the XRF analysis, including one local tachylyte source, two southern Washington sources, five central Oregon sources, and one western Idaho source. While questions about source frequencies through time could not be definitively answered, an intra-site comparison across space showed more sources represented in southern excavation units than in units from the northern end of the site. Source variation across technological class was highest in bifaces and lowest in cores, while an inter-site comparison with three southern Cascade sites did not show a direct correlation between distance from source and source abundance at any of the sites. For her work on this project, Anne Parfitt was named the SOURCE 2014 Scholar of the Year