First archaeomagnetic secular variation curve for the Iberian peninsula : Comparison with other data from Western Europe and with global geomagnetic field models

Miriam Gomez-Paccard (1) , Annick Chauvin (1) , Philippe Lanos (2) , G. Mcintosh (3) , Maria-Luisa. Osete (3) , Gianluca Catanzariti (3) , V.C. Ruiz-Martinez (3) , J.I. Nuñez (3)

1 GR - Géosciences Rennes
2 C2A - Civilisations atlantiques & Archéosciences
3 Departamento de Física de la Tierra

A first secular variation (SV) curve for the Iberian Peninsula was computed by hierarchical Bayesian method using a total of 134 archaeomagnetic directions with ages ranging from -775 to 1959 A.D. A general agreement is observed between the Iberian curve and the French and German SV curves, although some interesting differences were found, such as the occurrence of lower inclinations between the 11th and 14th centuries in the Iberian curve. The analysis of these three reference curves indicates that SV in western Europe is characterized by three major directional changes at -125, 200, and 1350 A.D. It is suggested that these cusps are regional features of the geomagnetic field. The Iberian curve has been compared with the predictions of the Jackson, CALSK7K.2, and Hongre global models. Despite large differences recognized between these models, even for the dipolar terms, they predict reasonably well the Iberian archaeomagnetic SV.

Mots clés: archaeomagnetism; geomagnetic secular variation; Bayesian statistics; Iberian Peninsula

Domaines: Géophysique [physics.geo-ph]

Miriam Gomez-Paccard, Annick Chauvin, Philippe Lanos, G. Mcintosh, Maria-Luisa. Osete, et al.. First archaeomagnetic secular variation curve for the Iberian peninsula : Comparison with other data from Western Europe and with global geomagnetic field models. Geochemistry, Geophysics, Geosystems, 2006, 7 (12), pp.Q12001. ⟨10.1029/2006GC001476⟩. ⟨hal-00128411⟩