Rehydroxylation (RHX) dating has recently been proposed as a new chronometric dating tool for use on archeological fired-clay ceramics. The technique relies upon the well-known characteristic of reheated porous ceramic vessels to regain water through a two-stage process (rehydration and RHX), where the kinetics of second stage has been shown to follow a (time) 1/4 power law at temperatures of 131-501C. In this study, experiments were conducted in which the mass measurements taken from 19th-century ceramic artifacts could be described by the (time) 1/n power law over a wide range of temperatures. This finding has led to the formulation of a new empirical equation, which describes the observed ceramic's rehydration and RHX behavior without the need for identification of RHX stage. As part of this study, the mineralogy of the ceramics and their thermal properties have been evaluated. The instantaneous effect of humidity on mass measurements was demonstrated to be the principal source of error. RHX dating shows promise, and after more research, the technique could become an important archeometric tool.

Rehydroxylation ceramic dating, a new technique that has shown promise as an archeometric breakthrough, was applied to XIX‐century samples of Davenport ceramics from Parowan, Utah in the United States. The samples were dried at 500°C to remove both physically and chemically bonded water and then exposed to a 20% relative humidity air to record the progression of rehydration/rehydroxylation over a period of 40 d. Both time1/4 and time1/n analyses were applied to the experimental mass gain versus time results in an attempt to find the most appropriate treatment for the data. The time1/4 analysis yielded poor reproducibility and nonideal fitting results to the Stage II mass gain, in which water reacts with meta‐clays. Application of the time1/n model, where “n” is the rehydroxylation exponent, improved the apparent linearity of Stage II mass gain in small samples. However, the time1/n treatment still provided a poor fit to data from larger specimens, indicating that some secondary effects related to sample size and water transport may exist. To examine the effects of porosity and macrostructure on rehydration/rehydroxylation processes, a pulverized sample of the same material was analyzed, resulting in improved sample‐to‐sample agreement in time1/n irrespective of mass variations. These findings have implications on the application of rehydroxylation ceramic dating.

No abstract

Since its introduction in 2009, application of the rehydroxylation (RHX) technique for dating fired‐clay ceramics has been controversial, with very few satisfactory dating results collected in the interim. The stability and efficiency of this technique has been called into question by several investigators in the last few years, who have struggled to reproduce and validate this new dating method. Based on our new mass gain measurements for ca. 2000–7000 yrs old ceramic artifacts, the reproducibility in the RHX process rate is analyzed and discussed. Timespan analysis was performed, and age uncertainty related to RHX dating technique was evaluated by considering the error propagation. The results show poor reproducibility of the RHX process in the samples of the same origins, which give new evidence for a revision of the RHX protocols.

No abstract