Possible Relationships between Seep Carbonates and Gas Hydrates in the Miocene of the Northern Apennines

In the Miocene of the northern Apennines, a widespread carbonate precipitation was induced by the expulsion of methane-rich fluids. Numerous outcrops of carbonate masses share sedimentological, textural and geochemical features with present-day gas hydrate-associated carbonates. We hypotesize the contribution of paleo-gas hydrate destabilization on the base of the heavy oxygen isotope signature, the presence of distinctive sedimentary features (breccias, pervasive non-systematic fractures, soft sediment deformation), the close association between seep-carbonates and sedimentary instability and the huge dimensions of seep-carbonates bearing brecciated structures.