“Dolomites and dolomites” in Mesozoic platform carbonates of the Southern Apennines: Geometric distribution, petrography and geochemistry

摘要: Abstract A multidisciplinary study of the dolomitized bodies present among Late Triassic to Cretaceous carbonate deposits Monti Lattari belt (Southern Apennines Italy) compares different dolomitization styles within this succession these Mesozoic platform carbonates and furnishes an overview their formative genetic models. The revealing traces diverse modes diagenesis in region include both surface subsurface mechanisms, utilizing: a geometric reconstruction bodies, integrated facies petrographic analysis components, geochemical characterization sediments including detailed mineralogy associated stable isotope values. data presented demonstrate that some intervals are characterized by surface-related processes (middle late Cretaceous), while others (latest Lower-Middle Jurassic), mainly dominated later, large-scale, processes. All middle (Norian) successions pervasively dolomitized, exhibit fabric-preserving textures have distinctly heavy signature. Their origin has been related due particular climatic palaeoceanographic conditions, leading formation extended blankets shallow, warm saline seawater. This setting was terminated changes during latest which dramatically reduced significance on regional scale. overlying, (Rhaetian) outcrops consist widespread coarse, fabric-destructive, massive dolomite with lighter isotopic These dolomites seem genetically ones Jurassic, share same geometrical, characteristics caused large-scale fluid circulation. diagenetic pattern apparently started Early burial, driven thermal convection temperatures between oceanic waters warmer platform. Middle-Upper Jurassic units feature local episodes early partially replaced muddy tidal pumping reflux mechanisms. Dolomitization is not pervasive phase deposition. In portion succession, totally distinct character generally bedding show variability Mg/Ca ratios. Local association evaporites, geometry geochemistry suggest comprising evaporative reflux, all environment. evidence points renewal context more favorable for dolomitization. Thus permits recognition presence three quite Southern fold–thrust belt: one ascribed Norian, Rhaetian/Lower Cretaceous.