Turbidite deposition of Oligocene to Early Miocene age occurred in the foreland basin to the Pindus mountains which formed the NNW-trending Hellenide thrust front. Deposition was interrupted by the migration of the deformation front westwards through the foreland basin itself. The Kalamitsi Thrust, exposed in West Levkas, became active in late Early Miocene times. A Miocene to Pliocene piggy-back basin developed, fed both from the thrust front to the west and the mountain belt to the east. During the mid–Late Miocene, deformation remained confined to the Ionian and Gavrovo zones, possibly related to the presence of lubricating evaporites which terminate in the Pre-Apulian zone to the west. During the Late Plio-Quaternary, inner arc extension (trenchward of the Hellenic arc) caused a system of ENE and WNW basins to open under the N-S tensional regime. These were linked by NNW and NE transtensional faults and the system is still active in the Lake Trikhonis and Gulf of Corinth areas today. In the west of the study area, however, post-Pliocene NW-SE compressional faults dissected the piggy-back basin. This compressional phase must have been either contemporaneous with or interrupted the extension active in the east from Late Pliocene times.