Authors: Nikola Stanković, Taras Gerya, Vesna Cvetkov, Vladica Cvetković

Abstract:
The ophiolites of the Balkan Peninsula are distinguished into the Western and the Eastern Vardar ophiolites and it is generally accepted that both of them resulted from the latest Jurassic/earliest Cretaceous closure of the Vardar branch of the Tethys Ocean (Vardar Tethys). This study is aimed at testing the possibility that the origin and emplacement of these two ophiolite belts can be explained in terms of a single NE-dipping intra-oceanic subduction, which commences in mid Jurassic and lasts until the lowermost Cretaceous, and then transitions into collision between the African and the European plate. The subduction is accompanied by creation of a new oceanic lithosphere in the back-arc. In order to test this hypothesis, we use 2D numerical thermomechanical modeling for investigating the nucleation of the East Vardar Ocean in the back-arc and intra-arc region. Our numerical results suggest that a single intra-oceanic subduction can indeed be simultaneously responsible for both the westward obduction of the Western Vardar ophiolites and for complex active margin processes along the western rim of the European plate. The simulations show that the single intra-oceanic subduction zone is able to produce a pronounced extension and oceanic spreading along the European margin, which can be associated with the formation of the Eastern Vardar ophiolites in this subduction related setting (SSZ and BAB). The comparison of the numerical modeling results with available natural data suggests that our models are capable to approximate the regional geodynamic evolution during and immediately after the closure of Vardar Tethys.