Miocene tectonic evolution of the southern Apennine thrust front (Italy): stratigraphic and structural constraints from the eastern Calabria-Lucania borderland area

Abstract

Syn-orogenic sediments provide fundamental information on the timing and modes of deformation in fold and thrust belts. In this study, biostratigraphic and structural analyses on syn-orogenic deposits have been carried out in a key area of the southern Apennines in order to constrain the evolution of the Miocene thrust front and adjacent foreland basin. Our data indicate that, by middle Miocene times, a thin-skinned fold and thrust belt had developed in the study area. This was characterised by a complex tectonic setting, including: (i) a wide foreland basin area to the NE, ahead of the thrust front, where volcaniclastic and then quartz-rich (“Numidian”) sandstones were deposited; and (ii) a series of thrust-top basin depocentres—hosting different siliciclastic and mixed detrital carbonate-siliciclastic successions— SW of the thrust front. Foreland propagation of the deformation produced intense folding of the foredeep succession. Later shortening and refolding around steeply dipping axial surfaces affected all of the tectonic units exposed in the study area. The latter deformation could be associated with Pliocene “en-masse” emplacement of the whole thin-skinned fold and thrust belt — as a major allochthonous detachment sheet—on top of the Apulian foreland sequence which presently underlies the exposed thrust sheets.