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

[1] 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 similar to6000 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 similar to6000 B.C. to similar to3500 B.C., with values of similar to30-40 muT. There was a significant increase in intensity by a factor of 2 from similar to3500 B. C. to similar to700 B.C., which was interrupted by a moderate decrease between similar to2550 B.C. and similar to1750 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.