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

Mario Borrelli¹, Bruno Francesco Umbro¹, Ulrich Heimhofer², Pierluigi Santagati¹, Emilia Le Pera¹ & Edoardo Perri^1
1Dipartimento di Biologia, Ecologia e Scienze della Terra, Universita della Calabria, Arcavacata di Rende, Cosenza, Italy. ²Leibniz Universität Hannover, Institut für Geologie, Callinstraße 30, D-30167, Hannover, Germany. Corresponding author e-mail: mario.borrelli@unical.it

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 (δ¹³C values between -6.8 and -38‰) and ¹⁸O enrichment (δ¹⁸O values between -0.04 to 3.4‰) reflecting destabilization of gas hydrates made of methane/crude oil mix.

cold seep, gas hydrate, chemo-symbiotic fauna, Lucinids, overpressure, conduit, pavement.