Tectonic evolution of the Crotone Basin (central Mediterranean): The important role of two strike-slip fault zones

Abstract

The middle Miocene to Quaternary evolution of the Crotone Basin (CB), on the Ionian side of the Calabrian Arc (southern Italy), was strongly controlled by the activity of the NNW- to NW-striking Rossano-San Nicola (RSFZ) and Petilia-Sosti (PSFZ) fault zones. The integration of low frequency 2D seismic reflection profiles, boreholes and geological maps has allowed the discovery of a positive flower structure, which is part of the RSFZ. Such a positive flower structure was responsible for the emplacement of an allochthonous unit in the Late Tortonian and contributed to the onset of gravitational collapse in the Pliocene. Dextral transpressional tectonics related to the RSFZ led to the expulsion of a S-verging thrust controlling the emergence of the northern sector (Cirò area), and the development of an elongated E-W-oriented depocenter in the southern sector of the Crotone Basin (Crotone area), from the Late Tortonian to Late Messinian. In the Late Messinian, the offshore area of the basin turned into a structural high marked by overall exposure conditions, as a consequence of the RSFZ activity. Contractional/transpressional activity also took place at the transition between the Early and Late Pliocene, when the PSFZ governed the superimposition of the Messinian Unit in the Crotone area. Conversely, phases of extensional/transtensional tectonics are inferred to have been occurred along the PSFZ during the Messinian, by the development of a tectonic trough in the south Crotone area. This tectonic regime is also supposed to have persisted during the Early Pliocene and the Pleistocene in the offshore area, where the development of local depocenters took place.