Obsidian Re-Use at the Rose Spring Site (CA-INY-372), Eastern California: Evidence from Obsidian Hydration Studies

We report on a re-analysis of the obsidian from Rose Spring (CA-INY-372), Inyo County, California, based on obsidian hydration dating. The computed projectile point ages for Desert Series, Rose Spring Corner- Notched, Elko, and Humboldt Basal-Notched points fall within the expected range, which gives con dence in the analytic technique. The projectile points are younger than the debitage, even though both points and debitage experienced similar temperature histories, and the age difference is statistically signi cant at the 95% con dence level. Five of the Rose Spring Corner-Notched points show evidence of having been reworked from earlier points. The debitage age data also show a dependence on depth, but not as strongly as the radiocarbon data, probably due to vertical mixing. Both the mixing and the earlier age for the debitage suggest that tool stone on hand as debitage was salvaged and reutilized for tool manufacture, as a substitute for logistical traveling to gather lithic material from its source in the Coso volcanic eld.