Geomorphological evolution of the Vendicari karstic coastal lake system (SE Sicily, Italy)

Povzetek

The Vendicari coastal lake system (SE Sicily) presents several geomorphic characteristics, which suggest it was originated as a part of a 6 km long karst polje during the Late Pleistocene sea level lowstand. Exhumed cryptokarst karren and terraced concentric surfaces point to this working hypothesis. The generation of this depression could have been favoured by the low to moderate neotectonic activity in the zone, which consisted in slight uplifting and subsequent fracturing. Open joints in the Vendicari Pleistocene carbonates show a radial outline with the prevalence of NNW-SSE discontinuities. Once formed, polje evolution would have consisted in a progressive compartmentalisation and splitting into several polje bottoms, some of which form a part of the present Vendicari lake system and are surrounded by stepped corrosion surfaces. The postglacial sea level rise had drowned most part of the original polje, which can be still recognized in the inner continental shelf. Sea level stabilization after the Holocene eustatic maximum favoured the development of a beach barrier, which generated additional coastal lakes of lagoonal type.