Testing rival tectonic uplift models for the Lechaion Gulf in the Gulf of Corinth rift

Abstract: The Gulf of Corinth, central Greece, is a rapidly extending continental rift, the eastern part of which bifurcates into the active northern Alkyonides Gulf and the southern Lechaion Gulf. The Lechaion Gulf is considered an inactive relict of early rifting, yet the presence of late Quaternary shorelines is evidence of continuing uplift of the north, east and south margins of this basin. Models to explain uplift include uplift on the footwall of the southern Alkyonides Gulf fault system and the Xylocastro–Perachora faults or ‘regional9 isostatic uplift independent of fault slip. These models are tested by comparing predicted spatial uplift trends with those observed. Uplift rates since Marine Isotope Stage 7 of 0.31 ± 0.04 mm a −1 on the Lechaion Gulf north coast are explained as displacement on the footwall of active faults. However, the south coast uplift cannot be explained by footwall uplift and is evidence for isostatic uplift that probably affects the whole of the southern Gulf of Corinth rift. Isostatic uplift rates of 0.22 ± 0.01 mm a −1 at the Corinth canal increase westward towards the mouth of the Lechaion Gulf where it meets the modern rift, the Gulf of Corinth. Supplementary material: Details of Holocene marine notches that identify raised shorelines from exposures on the southern Perachora peninsula between Heraion and Loutraki, and of the cumulative displacement of sequences by minor faults on the Isthmus, exposed in the Corinth canal walls, are available at http://www.geolsoc.org.uk/SUP18429.