Radiocarbon dating as a key to the past

Component-specific radiocarbon dating as a key to the past

Participants: Prof. Sabine Fiedler

In cooperation with the Johannes Gutenberg University of Mainz, CEZA is working on the further development of ¹⁴C dating on biomarkers.

Depending on the storage environment, datable organic remains can be preserved for a very limited period of time. In geoarchives (sediments, soils) they are usually only present discontinuously, which considerably limits the reconstruction of (pre-)historical environmental and living conditions. This is aggravated by the fact that organic remains were often relocated before they were deposited. Older remains introduced into younger sediments inevitably lead to misinterpretations. During storage, an input of younger carbon (e.g. humic acids, lime) can mask the older carbon.

The dating of bones and wood (carbon) stored in geoarchives is therefore particularly critical. Modern chemical processing methods, such as those used in the ¹⁴C laboratory facility funded by the Klaus Tschira Foundation, can often remove these contaminations. However, in special cases it has been shown that a complete removal is not possible, which excludes a dating in these cases. This mainly affects archaeological samples but also forensically relevant samples.

The aim of the project is to overcome the difficulties mentioned above by direct ¹⁴C-dating of single biomarkers (component-specific ¹⁴C-dating). Some of these biomarkers are stable over long periods of time. Their molecular fingerprint allows conclusions to be drawn about their origin, without the organism from which they originate still being visible itself. Existing methods are being further developed to eliminate matrix effects that can be expected in different materials and to enable component-specific age determination of n-alkanes, steroids, fatty acids, lignin and amino acids.