Stable isotope and compositional analysis of Alaska caribou teeth embedded in polymethyl-methacrylate (PMMA)

摘要

Stable isotopic analysis (SIA) of incremental dental tissues from archaeological specimens provides unique insight into the paleoecology of animals utilized by humans in the past. Unfortunately, many archaeological specimens are too fragile to survive the mechanical processes necessary to accurately identify and sample incremental dental tissues. Polymethyl-methacrylate (PMMA) is an organic polymer often used to encapsulate and strengthen archaeological specimens for the sectioning, grinding, and polishing necessary to identify incremental tissues. The effects of PMMA embedding on stable carbon and nitrogen isotopes in dental enamel and dentin has not been assessed previously and may be relevant whenever stable isotopic analysis of carbon and nitrogen is to be conducted. We embedded five caribou (Rangifer tarandus) tooth halves in PMMA, sampled these halves and the corresponding non-embedded tooth halves. We found that PMMA embedding has no noticeable effects on the nitrogen values of embedded specimens. PMMA embedding decreased the delta C-13 values of whole teeth powder by an average of -6.5 parts per thousand and increased %C by an average of 8.7%.