Late Cenozoic Evolution and Present Tectonic Setting of the Aegean–Hellenic Arc

The Aegean–Hellenic arc is a deformed sector of a long heterogeneous orogenic system (Tethyan belt), constituted by an inner old metamorphic crystalline core flanked by younger chains of European and African affinity, running from the Anatolian to the Pelagonian zones. Due to the convergence between the Arabian promontory and the Eurasian continental domain, the Anatolian sector of that belt has undergone a westward extrusion, accommodated by oroclinal bending, at the expense of the surrounding low buoyancy domains. Since the late Miocene, when the Aegean Tethyan belt collided with the Adriatic continental promontory, the southward bowing of the Aegean–Hellenic sector accelerated, leading to the consumption of the Levantine and Ionian oceanic domains and to the formation of the Mediterranean Ridge accretionary complex. The peculiar distribution of extensional and compressional deformation in the Aegean zone has mainly been influenced by the different rheological behaviours of the mainly ductile inner core (Cyclades arc) and of the mainly brittle outer belt (Hellenic arc). The bowing of the inner belt developed without involving any major fragmentation, whereas the outer brittle belt underwent a major break in its most curved sector, which led to the separation of the eastern (Crete–Rhodes) and western (Peloponnesus) Hellenic sectors. After separation, these structures underwent different shortening patterns, respectively driven by the convergence between southwestern Anatolia and the Libyan continental promontory (Crete–Rhodes) and by the convergence between the Cycladic Arc and the Adriatic continental domain (Peloponnesus). A discussion is given about the compatibility of the observed deformation pattern with the main alternative geodynamic interpretations and with the Nubia–Eurasia relative motions so far proposed.