The palaeomagnetism of Lesbos, NE Aegean, and the eastern Mediterranean inclination anomaly

Palaeomagnetic results for 44 sites in 16-22 Ma volcanic rocks from Lesbos, NE Aegean, yield a mean pole at 81.8 degreesN, 178.1 degreesE, K = 9.0, A( 95) = 7.6 degrees. The mean direction for these sites (D =4.3 degrees, I = 48.5 degrees, k = 10.8, alpha (95) = 6.9 degrees) is 5.9 degrees +/- 6.1 de grees shallower than the reference direction for Miocene Lesbos calculated from Besse & Courtillot (1991). Combining these new data with previous work yields a mean inclination that is 5.6 degrees+/-4.7 degrees too shallow. E xperimental problems, magnetic anisotropy, the magnetic terrain effect, geo magnetic anomalies, and problems with the reference path all seem unable to account for this observation. Shallow inclinations are a common feature of the Aegean region: 17 of 18 palaeomagnetic studies on Cenozoic igneous roc ks have returned an inclination that is shallower than expected. Northward motion of the Aegean block by similar to 500 km with respect to northern Eu rope would account for this observation.