OBSIDIAN OCCURRENCE AND FREQUENCY FROM THE UPPER MIDDLE AND LOWER UPPER COLUMBIA RIVER
Abstract
Previous lithic studies have documented obsidian occurrence in the central Washington archaeological record. Those efforts have focused on the implications of stone tool source proximity as well as the selective conditions for stone tool cost and performance. The following research will use a scientific evolutionary archaeology comparative framework to further investigate obsidian stone tool occurrence in the upper Columbia River valley. Twenty-seven archaeological sites were identified containing 545 obsidian artifacts, and 82 were sent for x-ray fluorescence geochemical analysis. A model of cost and performance was used along with a paradigmatic classification analysis to identify inter-variable relationships across stone tool provenance, material, technological, and functional attributes. Results indicated that selective conditions favored non-local, high-quality obsidian sources that occurred across the majority of object types and reduction classes. Source diversity appears to increase over time and space.