RADIOCARBON DATING OF MORTARS - AN OVERVIEW

• Y. Facorellis, N. Zouridakis (Laboratory of Isotope Hydrology, Institute of Physical Chemistry, N.C.S.R. "Demokritos", 153 10 Aghia Paraskevi Attikis, Greece)

The ¹⁴C method, which is used for the radiocarbon dating of organic samples, is very well studied for more than 50 years. Several hundred thousands samples have been dated so far all over the world and their ages have been given to the archaeologists. The chemical pre-treatment and the preparation steps of different types of samples are so well studied that constitute routine techniques. On the other hand, the radiocarbon dating of ancient mortars remains always a very important problem with both scientific and research interest. This is due to the added inert material, which may contain carbonate minerals, as well as fragments of land snails or seashells of different ¹⁴C content than the mortar itself.

In the Laboratory of Isotope Hydrology of N.C.S.R. "Demokritos" we have dealt with this triggering problem since 1985, whose radiocarbon unit was the first to produce radiocarbon dates in Greece (Diros Neolithic cave). Our research yielded specific indications towards to the obtainment of reliable ages. It is based on the determination of the ¹⁸O/¹⁶O and ¹³C/¹²C isotopic ratios using a mass spectrometer.

In this paper an overview of several methodologies proposed in the literature for the dating of mortars will be presented, as well as a series of radiocarbon dates of mortars of known historical age.