Atlante delle litofacies e modello deposizionale dei Calcari a Briozoi e Litotamni nella piattaforma carbonatica laziale-abruzzese

摘要: The Miocene carbonates of the Latium-Abruzzi carbonate platform are known as «Calcari a Briozoi e Litotamni» Formation. strata unconformably overlie Cretaceous and, locally, Palaeogene limestones. age transgression ranges from Late Aquitanian to Langhian (BRANDANO, 2001; BRANDANO et alii, 2001). By times, deposition was terminated by siliciclastic sedimentation because eastward migrating thrustbelt-foredeep system. Twenty-four stratigraphic sections were measured in domain. On basis components and textural characteristic 32 lithofacies distinguished, grouped 4 lithostratigraphic units that reflect different environments. sediment-producing biota belong rhodalgal subordinately chlorozoan associations photic zone, molechfor bryomol aphotic depositional profile, obtained using relative position facies belts dependence some skeletal upon light penetration, is homoclinal ramp. profile result both inherited substratum (the platform) locus production accumulation. ramp can be divided into three environments: inner ramp, middle outer characterized an high-energy environment immediately below littoral zone with sea grass meadows associated Maerl coral carpets (sensu RIEGL & PILLER, 2000). Local limited emersions testified Microcodium. ichnogenera assemblages indicate took place euphotic POMAR, 2001a) at water-depths few tens meters 2003). In main producers larger foraminifera (Heterostegina, Operculina, Amphistegina) red algae echinoids, bryozoans bivalves. Based on associations, located oligophotic 2001a). sub-divided proximal, intermediate distal proximal represented bryozoan colonies, bivalves (pectinids oysters) echinoids; benthonic common. scattered rhodolith levels absence suggest placed passage zone. dominated planktonic foraminifera, echinoids bivalve fragments. assemblage mainly characterised silica sponge spicules subordinately, echinoid sedimentological features lower part succession, presence small Porites patch-reefs, occurrence Heterostegina, Amphistegina foraminiferal assemblages, Sporolithon Lithoporella association shows tropical setting. scarcity sediments setting well explained high nutrient flux (cf. HALLOCK SCHLAGER, 1986). Abundance nutrients promotes increase bioerosion fleshy algae, coralline growth rather than reef-building corals (HALLOCK 1986; JAMES, 1997). observations succession agreement elevated under conditions. study area paleogeographical affected Neogene tectonic interaction between European African plates, leading peri-Mediterranean oro