Electron Spin Resonance (ESR) among the Quaternary dating methods: potential and current limitations
Geochronology has a key role in Modern Archaeology and Geology due to the increasing need of reliable numerical ages for any Quaternary locality or sequence under investigation. If nowadays there is a wide range of chrononometric dating methods available, some of them are apparently more powerful than others: radiocarbon, Ar-Ar or U-series (U-Th) are usually considered as reference dating methods since they have reached a relatively high level of standardization and they can provide accurate age results with a very high precision. However, even these tools have limitations, and this is why the development of alternative, less conventional, methods is essential. Electron Spin Resonance (ESR) is one of them, like Luminescence or Terrestrial Cosmogenic Nuclides methods.

Similarly to Luminescence, ESR dating is a palaeodosimetric method based on the detection and quantification of the trapped charges accumulated over time in the crystal lattice of some materials due to their exposure to natural radioactivity. If ESR cannot reach a level of precision similar to that of the radiometric dating methods, it is nevertheless characterized by a large variety of possible applications, which permits covering almost any geological contexts during the last 2.6 Ma. Among them, the ESR dating of fossil tooth enamel and optically bleached quartz grains are probably the most promising, since these materials are commonly found in geoarchaeological context. In particular, recently published works about the Rising Star complex (H. naledi, South Africa) and Djebel Irhoud site (Morocco) have shown the importance of direct dating human remains by ESR.

In this presentation, I will give an updated overview of the potential and current limitations of the ESR method, taking some examples of recent dating applications performed at different Early to Late Pleistocene localities. A special attention will be also given to practical aspects of the analytical procedure that should be especially taken into consideration when ESR dating is envisaged at a given site, in order to avoid future complications in the dating process.

Dr Mathieu Duval is an ARC Future Fellow in the recently inaugurated Australian Research Centre for Human Evolution (ARCHE) at Griffith University. He has previously worked for 7.5 years (2009-2016) as Research Scientist and Head of the ESR dating laboratory at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos, Spain. Between 2014 and 2016 he was the recipient of a Marie Curie International Outgoing fellowship. He received his doctorate in Prehistory from the Museum National d’Histoire Naturelle (Paris, France) in November 2008.

Dr Duval is a Quaternary geochronologist specialising in Electron Spin Resonance (ESR) and Uranium-series dating methods. Over the last ten years, he has developed an innovative research profile which combines methodological as well as dating application studies in geo-archaeological contexts. So far, most of his investigation has been dedicated to the development and application of the ESR method to Early Pleistocene hominin sites in Europe, by dating either fossil teeth (via the combined uranium-series/electron spin resonance (US-ESR) dating approach) or optically bleached sedimentary quartz grains. The results of this work have contributed to refine the age of some of the oldest archaeological sites in Southern Europe and Northern Africa (e.g., Atapuerca Gran Dolina, Barranco León, Fuente Nueva-3, Vallparadís EVT7, Ain Boucherit). He has also recently participated to the direct dating of key human fossils such as Homo naledi from the Rising Star complex (South Africa), the oldest Homo sapiens found outside Africa, at Misliya Cave (Israel), or the human finger bone from Saudi Arabia. His current Future Fellowship project aims to evaluate the timing and synchronicity of the Mode 1 and Mode 2 settlements across the Mediterranean by building more robust chronologies for Early Pleistocene sites located in non-volcanic context, a major challenge in Quaternary geochronology and Mediterranean archaeology.


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