Verónica Guilarte, from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos (Spain), leads a work recently published in the journal PLOS ONE presenting the results of the first detailed evaluation of the potential of Q-band Electron Spin Resonance (ESR) spectroscopy for dating fossil tooth enamel.

This innovative methodological study was carried out on a number of fossil teeth from various European archaeological and paleontological sites. It shows that Q-band provides sensitivities ~ 20 times higher than those reached using X-band. This astonishing increase in sensitivity offers the advantage of working with an extremely reduced amount of sample (less than 4 mg), in comparison with X-band.

This fact could be essential to study highly valuable fossils remains such as hominin teeth. In addition, the higher signal resolution achieved in Q-band is of special interest for the analysis of complex signals measured in fossil teeth or other Quaternary materials, such as corals, speleothems or molluscs.

Nevertheless, the key point of the study is the methodological effort carried out by the authors. They have examined numerous variables and their consequences for determining the doses, and consequently the age of the samples. In summary, the results indicate that ESR spectroscopy using Q-band can now be considered as a reliable tool for ESR dating/dosimetry of fossil teeth.

Electron Spin Resonance
ESR dating method is usually considered as a landmark in Quaternary Geochronology, as it allows dating fossil remains beyond the time range covered by the Radiocarbon method. So far, X-band frequency has been almost exclusively employed in ESR dating studies. However, the recent progress of microwave technology has facilitated the use of other frequency bands, such as Q-band, whose potential remains still almost unknown.

The recent acquisition of a Q-band ESR spectrometer by the CENIEH, co-financed by European Regional Development Fund (ERDF) allocated by the Spanish Ministry of Economy and Competitiveness, will allow to further study the possibilities offered by this interesting technique in the dating field.

This study entitled “Evaluating the potential of Q-band ESR spectroscopy for dose reconstraction of fossil tooth enamel” is a result of a Franco-Spanish collaboration between researchers from the CENIEH and the Institut de Radioprotection et de Sûreté Nucléaire (IRSN, Paris, France).