Tectonic evolution of the Timok Magmatic Complex in the Serbian Carpathians: Insights from basin-scale field kinematic study

The Timok Magmatic Complex (TMC), part of the Late Cretaceous Apuseni–Banat–Timok–Srednogorie (ABTS) volcano-sedimentary belt in the Carpatho-Balkanides, represents a well-exposed case study of a basin that developed within the overriding plate above two adjacent subduction systems of opposite polarity, the NE-dipping Neotethys and the W-dipping Ceahlău–Severin. This study reconstructs the tectonic evolution of the TMC basin through field-based structural and kinematic analysis, with the aim of constraining the controlling mechanisms of deformation in a multi-slab setting. The results define three successive deformation phases. The oldest phase records Late Cretaceous extension and asymmetric basin formation, characterized by strong strain localization along upper-crustal normal faults. This phase was controlled by rollback of the Neotethyan slab, enabling efficient transfer of deformation into the upper crust and direct coupling between active faulting and calc-alkaline magmatism. At the scale of the ABTS belt, this coupling was not uniformly developed, but is most clearly expressed through the development of the TMC basin. The subsequent phase corresponds to the latest Cretaceous–earliest Paleogene basin inversion, expressed by a progressive transition from contractional to transpressional deformation. This stage was controlled by the closure of the Ceahlău–Severin Ocean and Carpathian collision, with shortening localized along inherited extensional basin structures. The youngest phase reflects Oligocene–Middle Miocene post-orogenic deformation. It is characterized by strain partitioning and strike-slip faulting related to oroclinal bending of the Carpatho-Balkanides, which controlled segmentation and sedimentary reorganization of the TMC basin and the broader ABTS belt.