Neogene cold seep carbonates in the Crotone Basin (South Italy)

A Neogene cold seep carbonate body crops out in the Crotone Basin and is characterized by a Conduit facies, made of authigenic carbonates filling the gas/ fluid escaping pipes and a Pavement facies made of early-cemented bioclastic and siliciclastic sediments colonized by a chemo-symbiotic fauna dominated by Lucinid bivalves. The conduit facies is composed of alternated mm-thick dark micritic and clear sparitic lamine rimming and inward accreting open fissures. Micrite exhibits microbial peloidal to dendrolitic fabrics, while sparry laminae shows prismatic-pyramidal to anhedral-subhedral crystals. The pavement facies is made of microbial boundstones, bioturbated mudstone/wackestones and packstone/grainstones passing into mixed arenites, all interbedded with syn-sedimentary breccias due to local overpressure conditions because of gas/fluid injections. Planktonic foraminifera are widespread and suggest a deep-water setting. Stable Isotopes analysis in all the facies shows 13C depletion (delta 13C values between-6.8 and-38%0) and 18O enrichment (delta 18O values between-0.04 to 3.4%0) reflecting destabilization of gas hydrates made of methane/crude oil mix.