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°N, 178.1°E, K = 9.0, A95 = 7.6°. The mean direction for these sites (D = 4.3°, I = 48.5°, k = 10.8, α95 = 6.9°) is 5.9° ± 6.1° 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° ± 4.7° too shallow. Experimental problems, magnetic anisotropy, the magnetic terrain effect, geomagnetic 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 rocks have returned an inclination that is shallower than expected. Northward motion of the Aegean block by ∼500 km with respect to northern Europe would account for this observation.