Eight thousand years of geomagnetic field intensity variations in the eastern Mediterranean

Agnès Genevey (1) , Yves Gallet (1) , Jean-Claude Margueron (2)

1 IPGP - Institut de Physique du Globe de Paris
2 EPHE - École Pratique des Hautes Études

Twenty new intensity determinations of the ancient geomagnetic field have been obtained from groups of potsherds and brick fragments from Syria. These artifacts, archeologically well dated from ∼6000 B.C. to approximately A.D. 1200, have been analyzed using the Thellier and Thellier [1959] method as modified by Coe [1967]. Intensity values have been corrected for the effects of anisotropy of thermal remanent magnetization and cooling rate. Our results indicate that field intensities were moderate in Syria from ∼6000 B.C. to ∼3500 B.C., with values of ∼30–40 μT. There was a significant increase in intensity by a factor of 2 from ∼3500 B.C. to ∼700 B.C., which was interrupted by a moderate decrease between ∼2550 B.C. and ∼1750 B.C. During more recent periods, our results show an intensity minimum approximately A.D. 200 and a maximum around the tenth century. Comparison with different data sets from the eastern Mediterranean and central Asia shows that geomagnetic field intensity variations were consistent at this large regional scale, at least over the last 5 millennia.

Domains: Geophysics [physics.geo-ph]

Agnès Genevey, Yves Gallet, Jean-Claude Margueron. Eight thousand years of geomagnetic field intensity variations in the eastern Mediterranean. Journal of Geophysical Research : Solid Earth, 2003, 108 (B5), ⟨10.1029/2001JB001612⟩. ⟨insu-01864329⟩