Low Eurasian Latitudes in the Late Jurassic: Evidence for True Polar Wander

Recently, data from Adria suggested a more southern position of Africa in late Jurassic times than expected from the apparent polar wander paths (APWP). Those southern latitudes were attributed to large-scale soutward plate movements of Eurasia and Africa in middle Jurassic - lower Cretaceous times, followed by a return to more northern latitudes (Muttoni et al., 2005). To test this scenario for Eurasia, we collected paleomagnetic samples from middle Jurassic to lower Cretaceous rocks, both in Crimea (Ukraine) and in the Pontides (northern Turkey), to determine their paleolatitudinal position. Large datasets were sampled to enable correction for the inclination shallowing in sediments using the elongation/inclination (E/I) method (of Tauxe and Kent, 2004). The results clearly show low paleolatitudes that position the southern margin of Eurasia ~1200 km further to the south than expected from the APWPs, in agreement with the data from Adria. However, we argue that large-scale plate movements during this time span are unlikely, because of the considerable amount of subduction zones surrounding the African and Eurasian continents in late Jurassic times, making large movements of the associated slabs in the mantle implausible. Therefore, we suggest that the low latitudes of our new Eurasian sites result from true polar wander (TPW) which is in agreement with the TPW scenario recently proposed by Steinberger and Torsvik (2008).