Heritage of Tethyan Oceanic Transform Faults Within Alpine Orogens: Paleomagnetic Evidence From the Shkoder‐Peja Transverse Zone (Northern Albania)

The Shkoder-Peja transverse zone (SPTZ) of Northern Albania marks the boundary between the Dinarides and Albano-Hellenides and is marked by a ∼100 km SW-ward shift of the ophiolitic nappe front. The SPTZ has been variably interpreted as a paleogeographic inheritance, a dextral strike-slip fault, the hinge of the clockwise (CW) rotating Albano-Hellenides, and a Miocene normal fault. Here we report on the paleomagnetism of 23 Triassic-Cretaceous sites from the Krasta-Cukali and Albanian Alps domains, located both within and north of the SPTZ. Six sites yielded only a pre-tilt magnetization, 14 sites were found to be remagnetized after late Eocene-Aquitanian tilt, and 3 sites showed both pre- and post-tilt magnetizations. Both pre- and post-tilt paleomagnetic directions yielded a ∼70° CW rotation with respect to Adria/Africa, except 9 sites from the Koman zone at the boundary with the ophiolitic nappe, which record a 38° ± 15° CW rotation. Thus, the well-known regional CW rotation of the Albano-Hellenides extends northward in the southern Dinarides, and the SPTZ is not a rotation boundary as previously assumed. The ∼70° CW rotation is interpreted as the sum of a 30° rotation associated with Late Oligocene-Aquitanian thrusting of the Krasta-Cukali nappe over the Kruja zone, plus the 40° Miocene-Pleistocene rotation well-documented in the external Kruja and Ionian zones of Albania. We suggest that the SPTZ is the heritage of a Lower-Middle Triassic transform fault of the Maliac Tethyan Ocean, later overprinted by the Lower Cretaceous obduction of the Vardar Ocean that rejuvenated Maliac since the Middle Jurassic.