INVESTIGATION OF THE POWER LAW DEPENDENCE OF OBSIDIAN DIFFUSION TEMPERATURE WITH HYDRATION THICKNESS AND ITS OBSIDIAN HYDRATION DATING IMPLICATIONS: Part II

Obsidian hydration dating (OHD) has been a concern of research into chronological issues of ancient obsidian artifacts. The OHD is based on the power law equation relating to hydration depth (measured microscopically or by SIMS), hydration rate and time. Experimental aged data at high temperature (ca 140 – 180 oC) from five geographically world dispersed obsidian sources (California, Mexico, Peru, New Zealand) and at low temperature (10-40oC) (New Guinea) are used to explore the functional dependence of obsidian diffusion temperature with hydration thickness and pixels. A consistent power law dependent model for hydration rim/year and pixels/year versus temperature has been revealed for the first time, extending earlier indication with fewer data. Combination in tandem of data of high T and low aged data as well as reconstructed low T data, are used. The exponents lie on average between 3.2 and 5.5; the coefficients of the equations exhibit uniformity; all sources with Umleang except NZ and the high T of NZ have E-11, all high T with Wekwok of the order of E-07. Use of this model has been provisionally applied to reported ages of archaeological obsidian blades from Easter Island, Napa Valley California, Japan, Ethiopia, Papua New Guinea and the first available results hint at a novel approach to OHD. Advantages and limitations are discussed.