Sea floor morphology of north-western Gulf of Corinth (Greece): combined impacts of Late Quaternary eustatism and active tectonics

Two high-resolution seismic reflection surveys (single channel sparker) were performed in the western part of the Gulf of Corinth. aboard HCMR’s R/V ALKYON, within the frame of SISCOR ANR Project. This intra-continental marine basin is related to Late Cenozoic to Present extension separating “continental” Greece from Peloponnese. The connection of this active rift with the Ionian Sea (Mediterranean) is nowadays a 62 m deep sill, a situation which implies possible separations during low stands of global sea level, especially the last ones (MIS 2 and MIS 6). The western part of the Gulf, which is the most seismo-tectonically active part, appears as a transfer zone with both normal and strike slip faulting, identified through a dense grid of seismic lines.
As a consequence, the offshore northern edge between the Mornos River delta and the Trizonia island shows a complex morphology due to the interaction between these structures, huge terrigenous feeding, deltaic development and sediment failures. Pre-Quaternary basement (Hellenids) was partly submitted to aerial erosion and paleodeltas are superimposed on the induced relief, visible at a depth of 110 m below Present sea level. The paleovalleys are filled with onlapping layered sediments, affected by several WSW-ENE and W-E oriented faults, part of them still active.
An attempt to decipher both sources of relief genesis and evolution is presented. Beside, location and slip rate of active faults are discussed.