Timing of the Albano‐Hellenic Paleomagnetic Rotation

The Aegean arc is the most prominent Mediterranean salient, characterized by significant paleomagnetic rotations along its limbs. Although it is well‐established that the external Ionian and Kruja zones of the Albano‐Hellenides underwent a ∼40° post‐Oligocene clockwise (CW) rotation relative to Africa/Adria, the rotation timing remains debated. Previous models mainly suggested either two (Miocene and Plio–Pleistocene) rotation episodes, or a single post mid‐Miocene rotation accelerating along time. Uncertainties reflect the contribution from local thrust tectonics and/or strike‐slip faults biasing the regional rotational trend. Here we present new paleomagnetic data from 41 sites located in the virtually continuous Eocene‐Early Pliocene sedimentary sequence of the Tragjasi thrust sheet (Ionian zone, SW Albania). Sampled layers lie on the backlimb of a 50 km‐long anticline subparallel to the regional orogenic trend and away from major strike‐slip faults. Twenty‐eight sites yielded reliable paleomagnetic directions carried by magnetite. The data set includes 15 normal, 11 reverse and 2 mixed‐polarity sites, yielding positive reversal and fold tests. Eocene to early Early Pliocene sediments consistently record a 35° ± 9° CW rotation, demonstrating that rotation in the external Albanides began not earlier than the late Early Pliocene (∼4 Ma). By assuming rigid orogen rotations, we get post‐4 Ma displacements reaching ∼100 km at Vlore and ∼150 km in Crete, corresponding to trench‐retreat rates of ∼3–4 cm/yr. We interpret this rapid, recent rotation as driven by enhanced Ionian slab pull, slab tearing beneath the Albanides, crust coupling across the Kefalonia‐Lefkada Fault, and ultimately westward propagation of the North Anatolian Fault.