In this paper we present and discuss data concerning themorphostructural evolution at Ustica Island (TyrrhenianSea, Italy) during Late Quaternary. New insights on the relative sea-level changes of Ustica are coming from datacollected during a geomorphological field survey around the island, togetherwith the bathymetric analysis of thesurrounding seabed and 14C datings on samples of speleothems, flowstones and marine shells found inside three selected sea caves.The survey was mainly accomplished on June 2015 through the first complete snorkel investigation off theabout 18 km-long volcanic coast of the island, which allowed to precisely define location, relationship andmorphometric features of coastal landforms associated with modern sea level.This study highlights the occurrence, for the first time in the Mediterranean, of tidal notches in correspondenceof carbonate inclusions in volcanic rocks. The elevation of the modern tidal notch suggests that no significantvertical deformations occurred in the southeastern and eastern sectors of Ustica in the last 100 years. However,the presence of pillow lavas along the coast demonstrates that Ustica was affected by a regional uplift since theLate Quaternary, as also confirmed by MIS5.5 deposits located at about 30 m a.s.l., which suggests an averageuplift rate of 0.23 mm/y. Radiocarbon dating of fossil barnacles collected inside the Grotta Segreta cave indicatean age of 1823 ± 104 cal. BP. The difference in height with respect to living barnacles in the same site suggeststhat their present elevation could be related to stick-slip coseismic deformations caused by the four earthquakesequences (two of which with Mw = 4.63 ± 0.46) that strongly struck the island between 1906 and 1924.
|Numero di pagine||13|
|Stato di pubblicazione||Published - 2017|