The Miocene Bismantova Fm. in the Vetto-Carpinetisyncline (Parma;Reggio Emilia Apennines):evolution of sediment provenance

The main framework components and the type of lithic fragments of the Bismantova succession, define three petrofacies which can be matched with distinct lithostratigraphic units: the shelf basal members (Pietra di Bismantova, M.Castelletto, Pantano and Cigarello), the Vetto and the Maroia turbidites.Shelf arenites from the basal members are hybrid arenites. They are characterized by abundant intrabasinal carbonate grains, such as shallow-water bioclasts of Miocene age, indicating a consistent intrabasinal supply during deposition. The terrigenous componentcontains serpentinite and serpentine-schist rock fragments. The latter have long been considered as diagnostic of an alpine source. In this study we suggest that these clasts were derived mainly from the underlying Epi-Ligurian Fms., which are very rich both in metamorphic and ophiolitic debris of alpine and apenninic affinity. This petrofacies, characterizingthe Bismantova lower members, spans from the Reggio Emilia to the Bologna Apennines. The deposition of the Vetto and Marola turbidites marks a change in source-rocks. In the Vetto areìites, a large population of lithic fragments such as micriiic limestones, siltstones, shales, indicates detrital contributions mainly from the sedimentary successions of the Ligurian units.The terrigenous material of the Marola arenites derived from various sedimentary units:carbonate Ligurian units, the shelfal calcarenitic and arenitic lithotlpes of the basal Bismantova succession, but mainly arkosic sandstones (Loiano or Monghidoro?) able to release abundant quartz and feldspar grains.