Growth of a subduction orogen: Deformation styles and exhumation patterns in the Dinarides-Albanides-Hellenides

Subduction orogens grow through frontal accretion and crustal underplating, with the modes of accretion controlled by the strength of the basal and wedge materials. However, in retreating subduction systems, where crustal thinning occurs, the mechanisms driving upper plate thickening remain poorly understood, and their surface expression is difficult to discern. The Dinarides-Albanides-Hellenides orogen in the Eastern Mediterranean provides a compelling case to investigate these processes and their impact on exhumation patterns. Evolved during the eastward subduction of Adria beneath Eurasia since the Late Cretaceous, the orogen shows along-strike variations in deformation style, controlled by the thickness of Triassic evaporitic décollement. In the north, the absence of a décollement resulted in basement-involved deformation, focusing Middle-Late Miocene to Pliocene exhumation at the orogenic front. In the south, thick evaporites facilitated basement-cover decoupling, limiting exhumation at the front while focusing Late Miocene–Pliocene exhumation in the interior through underplating. In the hinterland, extension-related exhumation progressively rejuvenated toward the foreland, from Middle Miocene to Pliocene, suggesting slab rollback as the primary geodynamic driver. Our results demonstrate that from the Middle Miocene to Pliocene, crustal accretion through underplating occurred at the same time as hinterland extension triggered by slab rollback. This tectonic phase likely marks the most recent stage of a long-term accretionary cycle that thickened the crustal edifice in a system with retreating subduction boundaries. Our findings highlight the dual role of crustal accretion and thinning in building and shaping the orogen and suggest a broader context of plate reorganization in the Mediterranean during the Miocene.