Heating mollusc shells - A radiocarbon and microstructure perspective from archaeological shells recovered from Kalba, Sharjah Emirate, UAE

This publication aims to shed light on the influence that prior heating (burning) of mollusc shells during human activity may have on the results of radiocarbon dating. We compare the geochemical and mineralogical composition of heated and unheated shells of Anadara uropigimelana and Terebralia palustris recovered from Neolithic and Bronze Age archaeological contexts at Kalba, Sharjah Emirate, in the United Arab Emirates (UAE). Our research examined whether the heating of shells impacts on the determination of reservoir effects, or whether in spite of heating, this material remains a viable material for precise 14C measurements. Our results show that both heated and non-heated shells of A. uropigimelana and T. palustris provide consistent results, although the mineral composition of the shells changes from aragonite to calcite. Our results are important, since some of our selection of shells did not initially appear to have been heated. A heating process will then usually be detected as a greyish, marble like structure when cutting the shells. As a result of this work, we have also developed insights into prehistoric cooking practices of shells collected in Arabia. Our results provide archaeologists and associated researchers with confidence when assessing the results of radiocarbon dating during their studies of shells that might have been heated.