A new study analyzing amino acids in a mollusk shell necklace shows that Bronze Age people likely used locally sourced material for personal adornments.
The research team used amino acid racemization analysis (a technique used previously mainly for dating artifacts), light microscopy, scanning electron microscopy, and Raman spectroscopy, to identify the raw materials used to make beads in a complex necklace discovered at an early Bronze Age burial site at Great Cornard in Suffolk, UK.
Researchers discovered that Bronze Age craftspeople used species like dog whelk and tusk shells, both of which were likely to have been sourced and worked locally, to fashion tiny disc-shaped beads in the necklace. The research is published in PLOS ONE.
The researchers included archaeologists, mathematicians, chemists, and physicists. Sonia O’Connor of the University of Bradford’s archaeological sciences department carried out the light and electron microscopy, and prehistoric jewelry specialist Alison Sheridan of the National Museums Scotland facilitated access to the Great Cornard necklace, which had been excavated by Suffolk Archaeology.
When the team first realized the tiny white beads had been made from shell, they wondered about its source. Had the shell been obtained locally or did it originate from a species from further afield, perhaps even the Mediterranean thorny oyster (Spondylus)?
The Mediterranean thorny oyster is a shell of long-standing symbolic and cultural significance, which was used on the European continent around the time when the Great Cornard necklace was made.
But this collaborative research, led by Beatrice Demarchi of the University York’s archaeology department and Julie Wilson of the departments of chemistry and mathematics, has shown this not to be the case, and has suggested an alternative possibility.
“Dog whelks and tusk shells were likely to be available locally so these people did not have to travel far to get hold of the raw materials for their beads,” Demarchi says.
“There is evidence, from elsewhere in Britain and further afield, for the use of tusk shells at various times in the past. This may well be because they are relatively easy to work and their hollow shape is very distinctive.”
“The statistical analysis used pattern recognition algorithms for taxonomic identification,” Wilson adds, “comparing the composition of the beads with a large database of shell amino acid compositions. Although we cannot know the origin of the beads for certain, our multidisciplinary approach provides additional evidence for the identifications.”
The European Commission supported the research with contributions from NERC, the Wellcome Trust, the Leverhume Trust, and others.
《An Integrated Approach to the Taxonomic Identification of Prehistoric Shell Ornaments》, Published on Journal 《Plos One》in June 17, 2014.