The Messinian succession of the Crotone Basin (southern Italy) I: Stratigraphic architecture reconstructed by seismic and well data

Abstract

The Messinian succession of the Crotone Basin, a forearc basin located along the Ionian side of the Calabrian Arc (southern Italy), is composed of resedimented gypsum, halite and siliciclastic subaqueous to continental deposits that are overlain by Lower Pliocene deep-marine marls. Integrated seismic and well data analysis have allowed the recognition of seven major stratal surfaces (S1–S7) of sequence stratigraphic significance and stratal units typified by diagnostic architectures, which allow to define three depositional sequences accumulated since the onset of the Messinian Salinity Crisis. This highlights an unusually complex stratigraphy that is interpreted as the result of the interplay between tectonics involving the basin and the Mediterranean-scale Messinian events. In particular, the surfaces S1 and S3, bounding the base and the top of the resedimented gypsum, and the uppermost surface (S7), bounding the base of the Pliocene succession, probably developed due to Mediterranean-scale events, specifically the onset and the end of the main base-level fall (S1 and S3, respectively) and the Early Zanclean reflooding (S7). The other surfaces are inferred to be related to basin-scale tectonics, although a relationship between local tectonics and pan-Mediterranean tectonic events linked to the Salinity Crisis cannot be ruled out. This, together with the evidence provided by other Messinian successions, raises the possibility that the base-level changes recorded in the Messinian deposits of the Mediterranean are more complex than previously thought, a possibility that deserves further investigations.