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Bedding-parallel dolomite seams occur in a clay-poor carbonate succession of the Apennines. The seams are composed of a high concentration of dolomite crystals compared to the hosting dolomitic limestone. SEM images document microcracking, and in many cases even crushing and fragmentation, of dolomite crystals and accumulation of non-carbonate insoluble material both along micro-stylolites within the seams and around dolomite crystals of the seams. We interpret the seams as hybrid structures between pressure-solution seams and compaction bands, which formed during burial. The euhedral dolomite crystals scattered in the micritic matrix represent the insoluble residue produced by the progressive dissolution of calcite. As calcite dissolution proceeds, the concentration of dolomite crystals increases, eventually resulting in a dolomite seam in which locally a dolomite crystal-supported texture is attained. At this stage, the dolomite crystals within the seam start to collide, crush and fragment, so that the dolomite seam behaves like a compaction band.

In recent years, contrasting seismic tomographic images have given rise to an extensive debate about the occurrence and implications of migrating slab detachment beneath southern Italy. One of the most pertinent aspects of this process is the concentration of the slab pull force, and particularly its surface expression in terms of vertical motions and related basin subsidence/uplift. In this study we focused on shallow-water to continental, Pliocene-Quaternary basins that formed on top of the Apennine allochthonous wedge after its emplacement onto a large foreland carbonate platform domain (Apulian Platform). Due to the thick-skinned style of deformation controlling the Pliocene-Pleistocene stages of continental shortening, a high degree of coupling with the downgoing plate appears to characterize the late tectonic evolution of the southern Apennines. Therefore, the wedgetop basins analysed in this study, although occurring on the deformed edge of the overriding plate, are capable of recording deep geodynamic processes affecting the slab. Detailed stratigraphic work on these wedge-top basins points to a progressive SE-ward migration of basin subsidence from c. 4 to c. 2.8 Ma over a distance of about 140 km along the strike of the Apennine belt. Such a migration is consistent with a redistribution of slab-pull forces associated with the progressive lateral migration at a mean rate in the range of 12–14 cm y–1 of a slab tear within the down-going Adriatic lithosphere. These results yield fundamental information on the rates of first-order geodynamic processes affecting the slab, and on related surface response.

The Parasicilide succession is a key element of the southern Apennine orogen, being originally located in the distal portion of the Apulian palaeomargin, at the Neotethys ocean-continent transition. The succession, presently included in the upper nappe complex of the thrust belt, has been described elsewhere as a ‘broken formation’. However, detailed investigations carried out in the Sele Valley point out that there the Parasicilide Unit is characterized by a coherent stratigraphy. Therefore, in the study area, these rocks form a coherent sheet of distal continental margin ⁄ oceanic sedimentary cover material included within the peri-Tyrrhenian mountain belt. Stratigraphic and structural constraints obtained from both pre-and synorogenic deposits – the latter including both foredeep and thrust-top basin sediments – suggest that the pre-orogenic part of the Parasicilide succession subsided into the Apennine foredeep in the first part of the Burdigalian. The studied rocks were then involved in thrusting prior to late Burdigalian ⁄ early Langhian times.

Imbricate units in the western Sicilian fold-and-thrust belt originated on the southern continental margin of Neotethys, and were deformed during the Neogene-Recent in response to convergence between the African and European Plates. Neogene-Pleistocene synorogenic sediments, deposited in flexural foredeeps and satellite piggy-back basins, contain a record of the belt’s evolution. Progressive migration of the thrust front southwards into the foreland has been documented, beginning in the Tortonian and continuing to the present-day particularly in western parts of the belt. In the eastern part, activity on Quaternary strike-slip fault zones has produced asymmetric flower structures and other interference structures. In this paper, we present two regional sections across the western Sicilian foreland-thrust belt system. These structural cross-sections extend down as far as the top of the Hercynian basement and integrate our field observations with previously-acquired well log, magnetic and seismic data. We show that complex interactions between the foreland-migrating thrust belt, which developed between the Late Miocene and the Pleistocene, and Pleistocene strike-slip faults led to the development of structural traps which constitute potential targets for hydrocarbon exploration.