Tectonic and exhumation history of the Albanian Dinarides orogenic belt

The orogenic belt of the Albanian Dinarides in the central-eastern Mediterranean results from the eastward subduction of the Adriatic microplate beneath Eurasia since the Early Cretaceous. The belt exhibits compression in the west, at the front of the wedge, and extension in the east, in the internal sector, and consist of NW-SE oriented geological domains that record a long and polyphasic evolution. In the Cretaceous, the obduction of Mid Jurassic ophiolite was followed by continental subduction that in the Eocene led to the development of a flexed foreland in the external Meso-Cenozoic platform-basin system. The progressive migration of the deformation is recorded in the westward decrease of the depositional age of syn-orogenic deposits. Tectono-stratigraphic evidence suggests the development of a W-verging fold-and-thrust belt emplaced along an evaporite decollement level, possibly from the Late Cretaceous in the internal domain to Early Miocene in the outermost unit. To investigate the evolution of the Albanian Dinarides, such as the timing of deformation and the spatiotemporal pattern of exhumation, structural geological, stratigraphic and thermochronological data have been integrated. Here we present our first apatite (U-Th)/He (AHe) and fission track (AFT) ages. Within the eastern, extensional domain, fully reset AHe ages from Permian granites range from 12 to 18 Ma. In the western units, where compressional deformation is dominant, AHe ages from Eocene to Early Miocene syn-orogenic sediments vary in space: to the east, they cluster in the range of 5 to 2.5 Ma, and to the west, they scatter over a large range older than 5 Ma. All AFT ages scatter between the Early Miocene and the Late Cretaceous.Altogether the cooling ages show a large-scale pattern characterized by a broad zone of young ages with no clear relation to the southwestward propagation of the fold-and-thrust belt, suggesting a mechanism of reactivation of the system during the Late Miocene-Pliocene. These processes contribute to an amount of exhumation that likely does not exceed approximately 3 km. In this framework, future studies will be essential to integrate the available deep seismic information with surface data, in order to develop a model capable of identifying the mechanisms responsible for the exhumation processes of the Albanian Dinarides.