Luminescence dating of Quaternary coastal deposits of Evoikos gulf (central Greece)
M. Kazantzaki, C. Athanassas, Y. Bassiakos & E. Tsakalos In E. Photos-Jones, Y. Bassiakos, E. Filippaki, A. Hein, I. Karatasios, V. Kilikoglou & E. Kouloumpi (eds), 2016. Proceedings of the 6th Symposium of the Hellenic Society for Archaeometry (Bar International Series 2780), Oxford: 207-214.
Evoikos Gulf in Central Greece has undergone substantial neotectonic and volcanic activity as well as sea level changes since at least the Early Quaternary. Hence, the establishment of a chronological framework during which environmental events took place is essential not only for understanding the geodynamic evolution of the area but also useful for forecasting impacts on vulnerable shorelines. Littoral sediments frequently encode coastal palaeoenvironmental changes, be it tectonic or eustatic. The ultimate purpose of this research is the investigation of the palaeoenvironmental events that affected the coasts of Evoikos Gulf during the Quaternary by taking advantage of luminescence dating. Here, we present preliminary results from a range of luminescence dating techniques, namely conventional Optically Stimulated Luminescence (OSL), Isothermal Thermoluminescence (ITL) from quartz and post-infrared Infrared Stimulated Luminescence (p-IRIRSL) from feldspars. Despite the abundance of quartz found in samples collected, natural luminescence signals using both OSL and ITL were found to be close to saturation while the obtained Equivalent Dose (De) values were broadly scattered, thus perplexing the accurate calculation of luminescence ages. Conversely, the use of p-IRIRSL at 290°C (PIRIR290) from feldspars, as an alternative to quartz luminescence dating, was proven more suitable as it demonstrated much higher saturation levels. Strikingly, the PIRIR290 methodology produced ages that go back to the later part of the Middle Pleistocene. It is to be noted here that it is the first time that such old luminescence ages have been reported for Greek coastal sediments. This paper presents preliminary luminescence dating results with special focus on the performance of the PIRIR290 methodology. Palaeoenvironmental implications of the obtained PIRIR290 ages are also discussed.