NMR and IR-imaging of mass transfer during rehydroxylation of fired clays for rationalizing a novel dating concept of antique artefacts

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Irrespective of the groundbreaking progress initiated by the introduction of the C14 radio-carbon method, there are still substantial uncertainties in the dating of archaeological assemblages. They are caused by the "radiocarbon Plateaus" in the calibration curves, which, in some periods, give rise to uncertainties up to 300 years in the dating ranges, even with the high precision in radioactivity measurement. The option of a novel access to the dating of artefacts, based on recording the rehydroxylation of antique ceramics and totally independent from C14 dating, was therefore highly welcomed by the worldwide archaeologists’ community. This novel method is based on the observation that the mass of ceramics, after having been fired, increases in proportion to only the quartic (rather than the square) root of time. Such a time dependence (becoming increasingly weak with increasing time) would potentially allow determining the time when a given ceramic artefact has been produced, i.e. when, by firing, it has been transferred into the dehydroxylated state and has started the process of rehydroxylation. However, so far there does not exist any satisfactory model explaining this peculiar time dependence.Within the present project, we aim at the application of two well-proven techniques of material characterization for contributing to the exploration of the elementary mechanisms giving rise to this remarkable, highly retarded time dependence of rehydroxylation. With both techniques, notably with different modifications of NMR spectroscopy and with micro-imaging by IR microscopy, we have performed extensive investigations of numerous host-guest systems, including the observation of matter release and uptake just as to be as well observed during de- and rehydroxylation as the key phenomena of the problem under study. In a series of test experiments, we have been able to demonstrate that both techniques are applicable to the materials of interest within the given context and that, moreover, we thus indeed have access to the information necessary for the scheduled model considerations.In both the test experiments and the conception of our future work, we have relied on the suggestions and the advice by leading experts in the field, including the discoverers of the time anomaly, and by "ambassadors" bridging the gap between material sciences and archaeology.