Searching for the fundamentals of rehydroxylation dating of archaeological ceramics via NMR and IR microscopy

Abstract

Chronology assumes a central role in the process of historical and archaeological reconstruction by allowing us to time the change and development of human societies. Dating provides a framework for linking individual events together. It is the backbone for historical narratives, and connections between environmental and archaeological records on a global scale. However, until today, establishing a reliable chronology for ancient human societies and civilizations using pottery has remained one of the most contested topics of scientific discourse. Although the field of chronology has been revolutionized by modern historical and archaeological critical methods, through assessing historical sources and material

NMR Studies of the Dehydroxylation and Rehydroxylation (RHX) of Clays with Respect to the RHX Dating of Ceramic Materials

“…Beidellite is a swelling material. We determined the exchange time of the beidellite interlayer H 2 O T1-water with additional adsorbed D 2 O T0-water in the previous study 4 as τ = 125 s ± 35 s by means of an equation similar to eq 1.…”

“…We determined a mean exchange time of τ = 64 h at 350 °C for illite, and activation energies of 39 kJ mol −1 for illite and 36 kJ mol −1 for beidellite in the respective temperature interval. 4 Our considerations have been based on the assumption that the structure of the material does not change during the H/D exchange (hydrothermal treatment) at these temperatures. However, new experiments showed that structures of the material decline in dependence on the exchange time.…”

“…Two of the samples used in this study are illite 14 (RM30) and beidellite 15 (SBId-1). Both are 2:1 layer type smectite clay minerals, which were used already in our previous work 4 and described there. For the present study, the beidellite material (Idaho, USA, SBId-1) was purchased from the Clay Minerals Society's Source Clays Repository, 16 and the illite material (Colorado, USA, RM30) is a courtesy of Kate M. Campbell-Hay.…”

“…11 Therefore, one strength of NMR spectroscopy related to RHX lies in the fact that 1 T0, T1, and T2 water (physisorbed, interlayer, and chemisorbed water). 4 The observation of the dynamics of a slow H/D exchange by 2 H MAS NMR spectroscopy of samples in a heavy-water atmosphere represents another strength of NMR spectroscopy related to the dynamics of RHX. In our previous work, 4 we studied the H/D exchange in two model clay minerals, illite, and beidellite.…”

“…4 The observation of the dynamics of a slow H/D exchange by 2 H MAS NMR spectroscopy of samples in a heavy-water atmosphere represents another strength of NMR spectroscopy related to the dynamics of RHX. In our previous work, 4 we studied the H/D exchange in two model clay minerals, illite, and beidellite. We heated the samples up to temperatures, at which the structures of illite and beidellite were not fully destroyed, 260 and 350 °C for beidellite and illite, respectively.…”