New 234U-230Th coral dates from the western Gulf of Corinth: Implications for extensional tectonics

Abstract

We derive rates of uplift of ∼0.7-0.8 mm/yr for the western end of the Gulf of Corinth, Greece, using geomorphic paleaoshoreline modeling. We calibrate the modeling with new 234U-230Th dates on the coral Cladocora caespitosa collected from raised marine terraces uplifted in the footwall of the active Psathopyrgos fault, the only major active normal fault, reported on published maps controlling the downthrown Rio Straits at the western end of the Gulf of Corinth. In this area of high (15-22 mm/yr) extension rates measured with GPS, the ratio of uplift-rate to extensional velocity is 0.025-0.035, much lower than values of 0.15-0.25 found further east in the gulf. These low values imply that if GPS extension rates are correct then mechanical/kinematic models developed for the eastern and central gulf may not be applicable to the western gulf.