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Abstract: Most archaeologists using obsidian hydration dating (OHD) in the United States develop hydration rates from association of obsidian hydration rims with dates based on radiocarbon, subsequently using the rate for chronometric analysis. The overall accuracy of the process has never been quantified. This paper reports an accuracy analysis in which sources of uncertainty are defined and modeled and their effects quantified. A Monte Carlo simulation is used to quantify errors from rate development, while uncertainties in age resulting from chronometric analysis are calculated analytically. For typical ranges of error values, hydration rate errors of ∼5% or less are achievable in the absence of systematic errors, with errors of chronometric age estimates ∼20–30% or less. [ABSTRACT FROM AUTHOR]

Archaeological quartz artifacts and naturally fractured quartz fragments occur in a variety of cultural and geological contexts worldwide. For dating such objects we have developed the new Quartz Hydration Dating (QHD) technique. It relies on the phenomenon of water diffusion into quartz leading to the formation of a hydration layer that can be measured by a hydrogen profiling technique, and diffusivity data connecting the layer thickness with the hydration time. We have obtained such data by induced-hydration experiments in the temperature range 60 to 200 °C and derived a general equation for calculating diffusion coefficients which was validated by results from dated artifacts. The main factors influencing the diffusivity are temperature, the crystallographic orientation, measured as the angle between surface of hydration and crystal c-axis, and initial H content of the quartz. The experimental results are discussed in the frame of a diffusion-reaction model from the literature. The time range of QHD is 100 ya to over 100K ya. The error of age determination is 35%, but may be reduced to 20% by controlling for material variability. QHD is applicable to single-crystal specimens and aggregates of single crystals. Apart from its application to archaeology and geology, the technique is suited for detecting fakes. [Copyright &y& Elsevier]