A non-destructive technique for chemical mapping of insect inclusions in amber

Synchrotron-based techniques offer a wealth of elemental, molecular, and structural insights in biological samples, but the application of these techniques to fossils is a relatively new development. Here we examine how synchrotron radiation micro X-ray fluorescence (SR µXRF) may be used to investigate the chemical composition of insects trapped in amber, while leaving the inclusions unaltered. Elemental distribution data could provide important information on tissue preservation in insect inclusions, as well as information on the processes involved in fossilization. By analyzing a series of ants (Hymenoptera: Formicidae) that range from modern material, to Eocene Baltic amber, and Late Cretaceous North Carolina amber, we investigate how variable preservation influences the results obtained through SR µXRF analyses, as well as the various merits and pitfalls associated with the application of this technique to amber inclusions. This work serves as an introduction to the underlying principles, strengths, and limitations associated with applying SR µXRF in a palaeontological context.