Clockwise vertical-axis rotation in the West Vardar zone of Serbia: tectonic implications

The Vardar-Tethyan mega-suture between the Eurasian and Adria (Gondwana) margins comprises remnants of oceanic lithosphere of Neotethys and distal parts of the adjacent continental margins including unconformable Late Cretaceous sedimentary cover and Cenozoic igneous rocks of post-obduction age. This study provides kinematic constraints for displacements and rotations affecting the Serbian part of the West Vardar and Jadar-Kopaonik units after the closure of the Neotethyan (= Sava) Ocean. The targets of the paleomagnetic research were Late Cretaceous sediments representing an overstep sequence and a wide variety of Oligocene-Earliest Miocene igneous rocks. The studied 48 sampling points were distributed within two segments of a narrow and 160km long strip of the Western Vardar zone, namely the wider Rudnik Mts. area to the north and the Kopaonik Mts. area to the south. The results of standard laboratory processing and statistical evaluation suggest that both studied segments of the Western Vardar zone were affected by 30 degrees-46 degrees clockwise vertical-axis rotation which must have taken place after 20Ma. It is proposed that clockwise vertical-axis rotation documented in the present study on one hand, and the previously documented counterclockwise vertical-axis rotation of Adria, on the other hand are related to large scale extension in the southern Pannonian basin.