Refining ORA Methods

Fatty Acid Degradation Studies

Fatty acids are the diagnostic compounds best preserved in ancient residues, and are often used as key biomarkers in the reconstruction of the phytochemical “signature” left in the residue which can then be connected with a source plant. However fatty acids can degrade, pending environmental conditions, whether the the depositional context of an artifact, the type of vessel, the ceramic fabric of its container, or subsequent storage conditions in museums or warehouses. While the endpoints of degradation pathways for major biomarkers are generally known, the pathways and range of intermediate products are not; moreover, some degradation pathways appear to be reversible. This creates uncertainty for archaeological scientists, who use both the presence of these biomarkers and the ratios between them to make source plant identifications. Birney Lab has begun systematic, tandem studies of photo- and thermo-oxidative degradation of fatty acid biomarkers appearing in Mediterranean commodities. We are working to develop qualitative and quantitative models for biomarker degradation both in isolated conditions and applied to archaeological substrates.

Modeling Clay Mineral Binding in Archaeological Ceramics

Birney Lab is exploring binding patterns evident between certain clay minerals and temper types and unsaturated fatty acids, studying their impact on the extraction and preservation of archaeological organic residues both in isolation and on ceramic substrates. The work has implications for the development of predictive models for the selection of archaeological samples with enhanced likelihood of organic preservation. This is a collaborative project between Birney Lab, OpenARCHEM, and the Center for Materials Research in Archaeology and Ethnology at MIT.