Structural style and tectono-stratigraphic evolution of the Neogene–Quaternary Siderno Basin, southern Calabrian Arc, Italy

The Neogene–Quaternary Siderno Basin is located in the southern Calabrian Arc, along an E–W transect including the Ionian side and part of the Tyrrhenian margin. The orogenic belt was generated by ongoing northward subduction of Ionian oceanic lithosphere beginning in the Early Cretaceous. Since the Oligocene, the area has experienced complex tectonics, including NW–SE-oriented pull-apart basins. The forearc region contains >2000 m of Oligocene-to-Quaternary strata that cover pre-Tertiary rocks. The succession forms an E-dipping monocline, with tectonic growth structures increasing upward. Erosional truncations and thickness variations suggest a different evolution for the Siderno Basin, which in comparison with northern and southern parts of the Ionian accretionary wedge, evolved differently during the Serravallian–Tortonian stages. NW–SE and NE–SW fault systems are dominant, the first exhibiting strike–slip and normal kinematics in the Nicotera–Gioiosa and Molochio–Antonimina fault zones. These structures were active during infilling of the Neogene basin, and represent a complex transfer zone. The NE–SW system shows two types of tectonic kinematics: (1) a compressive stage, with NW–SE-orientated shortening, responsible for inversion tectonics documented by east-verging folds, thrusts, and back-thrusts, and (2) emplacement of the variegated clay during the Langhian, which is related to back-thrust propagation. The strike–slip accommodated stress generated in the accretionary prism in response to subduction of Ionian lithosphere and progradation of the accretionary front of the Calabrian forearc.