The Corinth rift, western Greece, developed from 5-4 Ma to present day and currently represents one of the fastest opening rifts in the world. It is the youngest expression of major lithospheric extension in the Aegean realm that began at 30 Ma and which is generally attributed to backarc extension above the SW retreating Hellenic subduction zone associated with the westward propagation of the North Anatolian Fault from 5 Ma. The E-W Corinth rift records northward and westward migrating and accelerating fault activity. It’s major faults cut at a high angle across older structures of the Peloponnese peninsula that record, firstly, W-SW emplacement of the Hellenide thrust sheets starting in the Oligocene and secondly, exhumation of high pressure rocks, which are exposed immediately south of the rift in the Feneos window. Metamorphism of this HP-LT Phyllite-Quartzite unit in the Peloponnese is dated at 25-18 Ma and records pressures equivalent to 40 km depth (Trotet et al. 2006). Exhumation of the HP units at the southern tip of the Peloponnese peninsula has been dated by the apatite fission track method at 9-12 Ma (Marcellos 2010). In the Feneos area extensional unroofing of the HP unit is overprinted by high angle normal faulting of the Corinth rifting. The dynamic relationship between these two extensional regimes has long been debated.
We present a new field investigation of the chronology, geometry and kinematics of extensional thinning of the Hellenide nappe stack in and around the Feneos tectonic window. We describe the transition from this regime to crustal scale extension that created the younger Corinth rift and discuss regional implications and controlling parameters.