Making eggshell visible in the archaeological record

Despite its presence in many types of deposit, eggshell has long been a neglected archaeological resource. The difficulty of recovering the material, combined with analytical constraints on subsequent taxonomic identification, has led to systematic underuse. This thesis will begin to address this shortcoming by pursuing two main lines of research. First, a novel identification technique based on ZooMS (zooarchaeology by mass spectrometry) and peptide mass fingerprinting is developed for eggshell. The new technique is then applied to archaeological eggshell assemblages from Anglo-Scandinavian York and Norse-era sites in the northern and western isles of Scotland. This provides new insights into egg use in these locations during this period, and raises a range of new questions regarding the use of domestic and wild resources. Second, an investigation into patterns of diagenesis in the eggshell proteins which form the basis of the technique is conducted. The principal aims of this analysis are to explore the prevalent diagenetic processes affecting eggshell proteins and amino acids, and thus to test whether it is possible to produce an estimate of the expected temporal span of the technique based on high-temperature diagenesis, and to establish the potential usefulness of the material for IcPD (intra-crystalline protein diagenesis) dating. The main outcomes of this study are (i) the development and successful application of a new taxonomic identification technique for archaeological eggshell; (ii) enhanced understanding of egg use during the Norse era in Scotland and Anglo-Scandinavian York; (iii) the observation that high-temperature diagenesis cannot be used to accurately predict peptide survival at archaeological deposition temperatures; and (iv) that avian eggshell is not a viable substrate for absolute dating using IcPD (although it may still prove useful for relative dating).