Pliocene-Quaternary transpressional evolution of the Anzi-Calvello and Northern S. Arcangelo basins (Basilicata, Southern Apennines, Italy) as a consequence of deep-seated fault reactivation

n this paper we report the results of a study of the Plio-Pleistocene Anzi-Calvello Basin and the northern sector of the S. Arcangelo Basin (Southern Apennines, Italy). Our work suggests that the evolution of the Anzi-Calvello Basin is related to the activity of a deep-seated, roughly NNE-trending, dextral transpressional fault zone. Structural control of sedimentation by this structure is indicated by the geometry of the unconformity-bounded stratigraphic units as well as by the deformation of the basin fill. En-echelon N-S-trending thrusts, N- to NE-trending dextral transpressional faults, and NW- to NNW-striking folds affecting the substratum, constitute the surface response to lateral displacement along the CTFZ. The S. Arcangelo Basin is bounded to the north by a deep-seated, roughly WNW/NW-trending, sinistral transpressional structure that terminates northwestward against the CTFZ. At the surface, the VLR is dominated by back thrusts and by transpressional fault zones. The VLR has been interpreted as the sinistral lateral ramp of the large-scale Valsinni thrust anticline and it is inferred to have strongly controlled local deposition within the S. Arcangelo Basin. The deep-seated structures (CTFZ and VLR) probably represent reactivated pre-existing normal and transfer faults affecting the rigid Apulian Platform that were generated during passive margin evolution, as well as during the flexural bending of the Apulian lithosphere. During the Pliocene-Pleistocene, these structures were reactivated as lateral ramps accommodating the thrusting within the Apulian Platform. Transpression along the lateral ramps in the Apulian Platform propagated upwards through the nappe pile, giving rise to a complex surface structural pattern and the local development of flower-like structures.