Geomagnetic field variations as a dating tool: Application to Sicilian lavas

Over 40 historically dated Mt Etna lava flows have been carefully sampled for the purpose of palaeomagnetic analysis. The natural remanent magnetization (NRM) of each lava flow contains a record of both the magnitude and direction of the Earth's magnetic field at the time of its eruption. Our analysis has thus enabled us to determine the change of the magnetic field in Sicily through historic times and to construct curves which show this secular variation of the field in both direction and magnitude. In this paper, the curves are used to reconsider the historical dates attributed to a number of Etna lavas, dates which had since been questioned by recent palaeomagnetic and geological studies. In a similar manner, these secular variation curves can be used as a powerful archaeological dating tool by comparison with the NRM of fired artifacts.