A geochemical approach to understanding raw material use and stone tool production at the Richardson Island archaeological site, Haida Gwaii, British Columbia

Archaeologists often base their classifications of rock type on informal visual assessments of the material which, unfortunately, can be erroneous. At the Richardson Island archaeological site in Haida Gwaii the raw material assemblage is diverse, and accurate rock type classifications can be used to explain possible behavioural relationships between raw material and selected stone tool types, and determine whether these relationships change through time. Thus, in this thesis, classifications for the most commonly occurring raw materials are established using macroscopic visual assessment of the lithic materials, major element compositions as determined through Electron Microprobe Analysis (EMPA), trace element compositions as determined through Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), and geological discrimination diagrams. Correlation matrices are used to show that both raw material and tool types vary through time. Bifaces, scraperplanes, scrapers, unimarginal tools, and microblades are then examined more closely for significant trends in raw material use. Analysis shows that patterns of raw material use vary between tool classes and through time, but that the patterns are not the same for all rock types. From this evidence we can postulate that formal tool categories have strict raw material requirements which influence the raw material used to manufacture less formalized tools.