Onset of the Messinian Salinity Crisis: Sedimentological, petrographic and geochemical characterization of the pre-salt sediments from a new core (Caltanissetta Basin, Sicily)

• Published in: Marine and petroleum geology Vol. 141; p. 105686
• Main Authors: Tzevahirtzian, Athina, Caruso, Antonio, Scopelliti, Giovanna, Baudin, François, Blanc-Valleron, Marie-Madeleine
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2022; Elsevier
• Subjects: Authigenic carbonates; Calcare di base; Earth Sciences; Evaporites; Messinian Salinity Crisis; Organic-rich sediments; Oxygen and carbon isotopes; Paleontology; Sciences of the Universe; Messinian Salinity Crisis; Evaporites; Organic-rich sediments; Authigenic carbonates; Calcare di base; Oxygen and carbon isotopes
• ISSN: 0264-8172; 1873-4073
• DOI: 10.1016/j.marpetgeo.2022.105686

The present study aims to reconstruct the environmental changes leading to the Messinian Salinity Crisis during the transition from the Tortonian-Messinian marine conditions to the Messinian evaporitic environments. The core 3AGN2S04, recently drilled in the Caltanissetta Basin (Sicily), was analyzed to reveal the petrographic, mineralogical and geochemical characteristics of the late Tortonian – early Messinian pre-salt sediments. In particular, the facies characterization of the carbonates and organic-rich shales of the Calcare di Base (CdB) member allowed to understand its significance in the paleoenvironmental evolution towards salt deposition and to the reconstruct the brecciation processes inside the CdB. The sedimentological and mineralogical analyzes revealed that core 3AGN2S04 consists of the inner shelf facies of the Tripoli Formation passing to the typical carbonate platform facies of the CdB. The local transition between the upper part of the Tripoli Formation and the CdB member indicates that stressful environmental conditions were constant in the central Mediterranean shelf zones during the late Messinian. The CdB carbonates indicate the occurrence of a carbonate platform characterized by peritidal environments rich in different microbial communities and evaporitic deposits, whereas the embedded organic-rich shales suggest a confined, low energy, anoxic and stratified saline system with high productivity and good preservation of organic matter. A complex set of syndiagenetic brecciation processes, interpreted as in situ brecciation, have profoundly marked the CdB deposits. •Pre-MSC and MSC sediments revealed by the recent drilled core 3AGN2S04 in the Caltanissetta Basin.•Sedimentary and environmental changes during the transition between Tortonian-Messinian evaporitic events.•The Calcare di Base member corresponds to a carbonate platform characterized by wide sabkha to lagoonal environments, rich in microbialites.•CdB deposits profoundly marked by a set of syndiagenetic and “in situ” brecciation processes.•Carbonate-shale alternations reflect cyclic dilution/evaporation environmental responses.