Radiocarbon dating and archeology

The current edition of the Annual Report of the Laboratory of Ion Beam Physics (7^th by LIBRUM Publishers) provides an insight into the exciting research conducted by the group. The AMS (Accelerator Mass Spectrometry) facility in Zurich has a 40-year history of interdisciplinary projects. Activities involve the development of instruments for AMS and material science and applications of the new measurement techniques. The first two chapters of the Annual Report 2019/Laboratory of Ion Beam Physics present status reports of routinely operating and newly developed devices. The following four sections combine summaries of the most recent research application projects. One of the sections is dedicated to Radiocarbon, an essential dating method applied in archeology.

At the ETH laboratory, the number of samples (1099) prepared and analyzed for archeological projects in 2019 reflects the importance of the interdisciplinary collaboration with archeology. Nearly half of all the 187 submissions originated from the Swiss archeological institutions. Moreover, the sample’s geographic location ranged from Madagascar, Ghana, Senegal, Israel through the Mediterranean region, the Alpine Foreland, Germany, Poland to England, Norway, and Finland.

The bones, charcoal, wood, peat, plant remains, and occasionally textiles or leather, which accompany excavated artifacts, are typical samples submitted for ¹⁴C dating. Nowadays, such a variety of materials used for ¹⁴C dating in the frame of archeological research is a common practice. Archeologists include various scientific tools to unravel the past hidden in the excavated grounds. The report by Gross et al., ‘Delta stories’ (p. 36), is an excellent example of such a multidisciplinary approach. With the help of the ¹⁴C ages of charcoal, wood, macro remains, the chronological frame for the anthropogenic and environmental changes in the region of lake Zug was established.

Moreover, the development of ¹⁴C techniques is most relevant to future archeological studies. The precise ¹⁴C radiocarbon and calendar ages will always require a milligram of carbon; however, the ability to measure tens of micrograms of carbon allows tracing contamination. For example, when re-visiting an old excavation and dating stored bones or wood, one might be faced with an unknown conservation history. As reported in a previous edition of LIP AR 2017 (p. 35), the ETH ¹⁴C laboratory applies the FTIR (Fourier Transform Infra-Red) analysis to detect and monitor contamination of the sample.

In summary, one can say that each year in the ¹⁴C laboratory is rich in archeological rarities, which could write a new page in Radiocarbon collections of Annual Report 2019/Laboratory of Ion Beam Physics/ETHZ. This year’s input is no different, despite the pandemic slowdown, I can estimate that archeology will again be a significant part of our Annual Report in 2020.

Irka Hajdas/ Laboratory of Ion Beam Physics, ETH Zürich

Annual Report 2019/Laboratory of Ion Beam Physics, ETH Zürich