Bismantova-Termina succession

This study aims to decipher and compare the dia-genetic evolution of hybrid arenites and arenites rich in carbonate rock fragments belonging to the Bismantova-Termina succession, a synorogenic sequence of the northern Apennines (Fig. 1). Special emphasis is given to the roles of the complex detrital composition, provenance and facies organization of the arenites in their carbonate cementation. 

Fig. 2. Schematic stratigraphy of the northern Apennines Epi-Ligurian sequences. (A) Upper Eocene-Lower Miocene succession. (B) Bismantova-Termina succession. S1-S4, depositional sequences B1-B3, arenite petrofacies. Bl, hybrid arenites B2, arkosic arenites B3, feldspathic lithic arenites 1, marls 2, resedimented arkosic and lithic arenites 3, hybrid arenites 4, silty marls. Modified from Amorosi Spadafora (1995).

Fig. 3. Simplified stratigraphical and lithofacies schemes of the Bismantova-Termina succession in the Bologna area B, Burdigalian L, Langhian S, Serravallian T, Tortonian. Modified from Amorosi (1992).

Table 1. Average and range of detrital, authigenic and textural components of the four defined depositional sequences (SI-S4) in the Bismantova-Termina succession in the Bologna area the number of samples is given in parenthesis...

Carbonate cements in the Bismantova-Termina succession include calcite and subordinate dolomite. 

Table 3. Isotopic values of representative diagenetic and detrital calcite in the Bismantova-Termina succession...

Fig. 8. 6 CpDB versus 5 Opdb plot of representative diagenetic and detrital calcite in the various depositional sequences of the Bismantova-Termina succession. Arrow denotes the probable derivation of S4 cements from marine carbonate rock fragments.

Calcite cementation in bioclastic hybrid and lithic arenites of the Bismantova-Termina succession is pervasive along layers and concretionary horizons. Cementation in the hybrid shelf arenites was mostly precompactional and began with marine calcite rims, syntaxial overgrowths on echinoderms, K-feldspar and dolomite overgrowths, chloritic clay rims, framboidal pyrite and heulandite, followed by... 

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