Amino acid racemization dating of marine shells: a mound of possibilities

Shell middens are one of the most important and widespread indicators for human exploitation of marine resources and occupation of coastal environments. Establishing an accurate and reliable chronology for these deposits has fundamental implications for understanding the patterns of human evolution and dispersal. This paper explores the potential application of a new methodology of amino acid racemization(AAR) dating of shell middens and describes a simple protocol to test the suitability of different molluscanspecies. This protocol provides a preliminary test for the presence of an intracrystalline fraction of proteins(by bleaching experiments and subsequent heating at high temperature), checking the closed system behaviour of this fraction during diagenesis. Only species which pass both tests can be considered suitable for further studies to obtain reliable age information. This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea.Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world

Amino acid racemization dating of marine shells: a mound of possibilities

Shell middens are one of the most important and widespread indicators for human exploitation of marine resources and occupation of coastal environments. Establishing an accurate and reliable chronology for these deposits has fundamental implications for understanding the patterns of human evolution and dispersal. This paper explores the potential application of a new methodology of amino acid racemization(AAR) dating of shell middens and describes a simple protocol to test the suitability of different molluscanspecies. This protocol provides a preliminary test for the presence of an intracrystalline fraction of proteins(by bleaching experiments and subsequent heating at high temperature), checking the closed system behaviour of this fraction during diagenesis. Only species which pass both tests can be considered suitable for further studies to obtain reliable age information. This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea.Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world

Integrated novel applications for dietary reconstructions in Prehistory

A broad range of biogeochemical techniques encompassing a wide array of disciplines is successfully being used to address key questions in archaeological research, including chronology, migration, trade, palaeopathology and palaeoenvironmental reconstructions. The aim of the session was to focus particularly on the developments in palaeodietary studies, which inform about population dynamics and socio-cultural characteristics of different communities over space and time. Biogeochemical techniques in particular have shown a remarkable adeptness at acquiring data from a variety of archaeological substrates, such as ceramics, lithics, textiles, sediments, plant remains, and human and animal tissues, including dental calculus. These techniques allow an intensive exploitation of archaeological material, especially organics, which are often preserved in small quantities and would otherwise not have been considered viable for analysis. The success of this approach is attested by the wide range of publications detailing the development and application of novel techniques, targeted towards answering fundamental archaeological questions. This was also reflected in the broad range of analytical methodologies presented during the session, which comprised bulk light and heavy stable isotope analysis that allows a better understanding of the composition of ancient diets, characterization of foodstuffs absorbed within ceramic vessels using lipid residue analysis, identification of protein sequences informing on dietary deficiencies, studies on microbial communities associated with the production of specific food types, and microscopic techniques used on teeth and dental calculus to recover palaeodietary information