Fault architecture, basin structure and evolution of the Gulf of Corinth Rift, central Greece

Abstract

ABSTRACTThe style of extension and strain distribution during the early stages of intra‐continental rifting is important for understanding rift‐margin development and can provide constraints for lithospheric deformation mechanisms. The Corinth rift in central Greece is one of the few rifts to have experienced a short extensional history without subsequent overprinting. We synthesise existing seismic reflection data throughout the active offshore Gulf of Corinth Basin to investigate fault activity history and the spatio‐temporal evolution of the basin, producing for the first time basement depth and syn‐rift sediment isopachs throughout the offshore rift. A major basin‐wide unconformity surface with an age estimated from sea‐level cycles at ca. 0.4 Ma separates distinct seismic stratigraphic units. Assuming that sedimentation rates are on average consistent, the present rift formed at 1–2 Ma, with no clear evidence for along‐strike propagation of the rift axis. The rift has undergone major changes in relative fault activity and basin geometry during its short history. The basement depth is greatest in the central rift (maximum ∼3 km) and decreases to the east and west. In detail however, two separated depocentres 20–50 km long were created controlled by N‐ and S‐dipping faults before 0.4 Ma, while since ca. 0.4 Ma a single depocentre (80 km long) has been controlled by several connected N‐dipping faults, with maximum subsidence focused between the two older depocentres. Thus isolated but nearby faults can persist for timescales ca. 1 Ma and form major basins before becoming linked. There is a general evolution towards a dominance of N‐dipping faults; however, in the western Gulf strain is distributed across several active N‐ and S‐dipping faults throughout rift history, producing a more complex basin geometry.