Journal of Mediterranean Earth Sciences Special Issue (2013), 35-37 Paleoecological, bio-sedimentological and taphonomic analysis of Plio-Pleistocene biocalcarenite deposits from northern Apennines and Sicily (Italy) Simone Cau 1 , Marco Taviani 2 , Vinicio Manzi 1 , Marco Roveri 1 1 Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parma, Italy 2 ISMAR-CNR Bologna, Bologna, Italy INTRODUCTION We have conducted a detailed study of conspicuous biocalcarenite bodies occurring at discrete time intervals within the Plio-Pleistocene sedimentary successions along the Apennine-Maghrebian chain. The genesis of such peculiar, more or less intensely carbonate- cemented, deposits has been hypothesized to respond to astronomical cycles (Roveri and Taviani, 2003). These bodies are best developed along slopes or steps on morphostructural highs. At places, biocalcarenites form prograding wedges typically displaying a tripartite geometry, whose topset horizontal strata are intensely bioturbated, and may contain abundant articulated bivalves and fragmented calcareous algae, whilst foresets and bottomsets are characterized by dense accumulations of reworked shells (Roveri and Taviani, 2003; Massari and Chiocci, 2006). These deposits are obviously different from tropical carbonate systems and are indicated with various terms (heterozoan sensu James, 1997, chlorozoan sensu Lees and Buller 1972). They are characterized by biological communities lacking hermatipical corals and coralline algaes supported by skeletal detritus. Other terminologies used are “temperate”, “non-tropical” and “cool-water” carbonates. Due to the usually abundant presence of benthonic foraminifers and molluscs these deposits are also indicated as “foramol” (Carannante et al., 1988). In recent decades, the origin of these biocalcarenite deposits has been deeply revised focusing on stratigraphic and sedimentologic analyses (Kidwell, 1991; Naish, 1997; Massari and Chiocci, 2006; Massari and D’Alessandro, 2012). However, no detailed studies have clarified their faunal composition, the sedimentary environments and the oceanographic phenomena involved in their formation. This study aims to fill this gap through a paleontological study using (i) the highly detailed examination of the skeletal components (shells), (ii) the clarification of the biota ecological structures that acted as sources of biocalcarenites, (iii) the identification of taphonomic and sedimentary processes that affected post-mortem shells. A better understanding of the physical characteristics, organization and space-time distribution (cyclical forcing) of these deposits may have important implications for the correlations of deep and shallow-water successions, an essential tool for exploration purposes and palaeoclimatic reconstructions. GEOLOGICAL OUTCROPS AND METHODS The research is being carried out on the Plio- Pleistocene biocalcarenites of the Castell’Arquato Basin, Enza Section (W-Emilia Apennines) and on the lower Pliocene “Spungone” unit (Romagna Apennines). At present also the analogous deposits of Tuscany (see Nalin et al., 2010) and Sicily (Caltanissetta and North Belice Basin; see Massari and D’Alessandro, 2012) have been preliminary analysed. In recent years the litho- and biomagnetostratigraphy studies in Castell’Arquato and Spungone area resulted in the reconstruction of the sedimentary evolution of these basins. In the Castell’Arquato Basin the integration of surface and subsurface data resulted in a comprehensive stratigraphic and evolutive model of the basin during the Pliocene (see Roveri et al., 1998; Monegatti et al., 2001; Roveri and Taviani, 2003). The thickest biocalcarenitic bodies are found in the transgressive systems tracts of three depositional sequences bounded by 3.1, 2.7 and 2.1 Ma unconformities. These deposits have a strong chronostratigraphic meaning as their stratigraphic distribution seems to be controlled by astronomical forcing (Roveri and Taviani, 2003), allowing their accurate dating and the correlation with coeval sapropel clusters characterizing deeper water successions. The stratigraphic evolution of Spungone area has been reconstructed basin through field mapping and detailed analysis of several stratigraphic sections (Capozzi and Picotti, 2002). This unit mainly consists of resedimented deposits from a carbonate platform, which is presently preserved only around Castrocaro (Rio dei Cozzi section). The Rio dei Cozzi carbonate factory developed during the lower Pliocene on the Castrocaro structural high; its deposits, rich in rhodolithes and shell-beds, unconformably overly the upper Miocene Marnoso Arenacea turbidites. The carbonate deposits show a vertical arrangement of facies clearly denoting a cyclical stacking pattern with an overall aggradational geometry; JME S Journal of Mediterranean Earth Sciences