séminaire – vendredi 20 février 2015

Ancient proteins in shells: what can they do for Palaeolithic archaeology?

Béatrice Demarchi, York University

vendredi 20 février à 11 heures , salle André Leroi-Gourhan, laboratoire ArteHis, 4e étage du bâtiment Gabriel


Mollusc shells are one of the most revealing materials that can be recovered from the archaeological record, yielding information on subsistence patterns and exploitation of the natural environment. Shells are also excellent repositories for fossil biomolecules, e.g. proteins, which are preserved for hundreds of thousands of years. Here I present two applications of the study of ancient shell proteins: new advances in amino acid racemisation (AAR) dating, and the taxonomic identification of worked or fragmented shells.
Amino acid geochronology is able to span the whole Quaternary and can be applied to a range of common materials which are directly related to the human occupation of an archaeological site: not only mollusc shells, but also avian eggshells. These are also preserved in sediments which accumulated as a response to global climatic pulses, during the Pleistocene and beyond. Therefore, amino acid geochronology has the potential to be widely applicable to the chronology of human evolution, as well as to the geological record.
 Shells were also important symbolic items in prehistory and theories of prehistoric exchange networks are founded on the long-distance movements of “prestige shells” and shell artefacts (e.g. Spondylus). However, when the shells are worked, the morphological features are lost and the identification of the raw material is difficult.  Using non-destructive SEM imaging and mineralogical analyses and micro-destructive proteomics and amino acid analyses, which exploit the fossil proteins trapped in shells as a taxonomic barcode, species identification is possible. This is allowing us to begin testing hypotheses on long-distance trade and communication networks, and exploitation of raw materials.