Obsidian Hydration Dating Formulas
Age = Rim^2 / Rate (in thousands of years)
Temperature Correction: Rate_adj = Rate * exp(E/R * (1/T_ref - 1/T_eff))
E = activation energy (~80 kJ/mol), R = 8.314 J/(mol*K)
Obsidian hydration dating measures the thickness of the water-absorbed rind that forms on freshly exposed obsidian surfaces. The hydration rim grows as a function of the square root of time. Diffusion rates vary by obsidian source chemistry (particularly silica and water content) and effective temperature.