The Aegean region experienced back-are extension related to the Hellenic subduction system at least from the latest Oligocene to the present. We document Tertiary extension-related kinematics in the north Aegean, in the eastern Rhodope–Thrace of Bulgaria–Greece and the Biga Peninsula of NW Turkey. A regionally consistent NNE–SSW- to NE–SW-oriented kinematic direction, delineated in both areas by stretching lineations and associated ductile–brittle shear fabrics in exhumed metamorphic domes beneath detachments, suggests that they were kinematically coupled during the Tertiary extension. This kinematic framework, combined with regional geochronological data and the stratigraphic record in hanging-wall supradetachment basins, defines an extensional history that includes syn- and post-orogenic episodes from Paleocene to Miocene times. Paleocene–early Eocene synorogenic extension in the Kemer micaschists of the northern Biga Peninsula and in the Kesebir–Kardamos dome in Rhodope–Thrace accommodated gravitationally induced hinterland-directed exhumation of the orogenic stack, coeval with the closure of the Vardar Ocean. Then, following collision within the region, it was succeeded by latest Oligocene–Early Miocene extension as recorded in the Kazdaǧ Massif in the southern Biga Peninsula, which overlaps the Aegean back-arc post-orogenic extension, widely recognized in the central Aegean and southern Greek Rhodope. The protracted record of extension is interpreted to reflect progressive exhumation of the orogenic wedge along the Eurasian plate margin. Southward migration of extension and magmatism across the study areas accounts for sequential shift and roll-back of the subduction boundary at that margin, from the latest Cretaceous in the Rhodope to its present position at the Hellenic trench. The results allow recognition of the investigated areas as an important extensional domain in the north Aegean region, which underwent Tertiary syn- and post-orogenic extension.

In NW Turkey, the medium-grade Kemer micaschists of the Biga Peninsula record NE-directed extension related to ductile to brittle–ductile shearing during the Palaeogene period: a lower limit for their exhumation is given by the Late Maastrichtian age of the HP–LT metamorphism of a similar nearby area (Çamlıca micaschists); an upper limit is given by the Early Eocene intrusion age of the post-kinematic Karabiga granitoid, dated as 52.7 ± 1.9 Ma using the U–Pb LA–ICP–MS method on xenotime. Correlations with the northeasterly Rhodope region and integration into the geodynamic regional frame indicate that the Kemer micaschists experienced an extensional deformation connected to a collisional context in latest Cretaceous–early Tertiary times. The Kemer micaschists therefore represent a new area (the first in Turkey), which suffered synorogenic extension in the north Aegean domain at the very beginning of Tertiary times.