Recent achievements in archaeomagnetic dating in the Iberian Peninsula: application to Roman and Mediaeval Spanish structures

Archaeomagnetic studies in Spain have undergone a significant progress during the last few years and a reference curve of the directional variation of the geomagnetic field over the past two millennia is now available for the Iberian Peninsula. These recent developments have made archaeomagnetism a straightforward dating tool for Spain and Portugal. The aim of this work is to illustrate how this secular variation curve can be used to date the last use of several burnt structures from Spain. Four combustion structures from three archaeological sites with ages ranging from Roman to Mediaeval times have been studied and archaeomagnetically dated. The directions of the characteristic remanent magnetization of each structure have been obtained from classical thermal and alternating field (AF) demagnetization procedures, and a mean direction for each combustion structure has been obtained. These directional results have been compared with the new reference curve for Iberia, providing archaeomagnetic dates for the last use of the kilns. The inferred ages obtained from this study are consistent with the archaeological evidence available.