[20-5] The record of the end-Triassic mass extinction in the Southern Apennines carbonate platform (Italy)

• Main Authors: Societa Geologica Italiana 2021, Montanaro, Andrea
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Ocean acidification
• Online Access: https://dx.doi.org/10.48448/vsw0-nj28; https://underline.io/lecture/33925-20-5-the-record-of-the-end-triassic-mass-extinction-in-the-southern-apennines-carbonate-platform-(italy)

Abstract: The end-Triassic mass extinction is one of the big five of the Phanerozoic. It is associated with severe perturbations of the global carbon cycle, recorded by the worldwide occurrence of a series of negative carbon isotope excursions (CIEs) in both the inorganic and organic marine carbon record. The massive injection of isotopically light CO2 into the atmosphere/ocean system from the paroxysmal volcanic activity of the Central Atlantic Magmatic Province has been invoked as the cause of the CIEs, of abrupt climate change, ocean acidification and mass extinction. In many areas of the Tethyan ocean, carbonate platform sedimentation was terminated around the T-J boundary. In the resilient carbonate platforms that were able to survive the crisis (e.g. the southern Apennine carbonate platform in southern Italy), fossiliferous limestones with corals, sponges, chetetids, large megalodontid bivalves and rich and diverse benthic foraminiferal associations, change abruptly into unfossiliferous peritidal and/or oncolitic-oolitic limestones around the T-J boundary. We have sampled in detail a 244m thick section exposed near the village of Valle Agricola, in the Matese Mts, about 65 km north of Naples (southern Italy). The lower interval (0-205m) is made up of peritidal cycles, consisting mainly of wackestone-packstone with benthic foraminifers and dasycladalean algae and wackestone to floatstone with large megalodontids, corals and chetetids, capped by microbial laminites and supratidal facies with microkarstic cavities. The upper interval (205-244m) is entirely made up of unfossiliferous grainstone-rudstone with ooids, oncoids and intraclasts. We use carbon isotope stratigraphy, tied to benthic foraminifera biostratigraphy, to correlate the Valle Agricola section with other previously studied sections in the southern Apennines, including the Monte Cefalo carbonate platform section and the Pignola-Abriola section in the Lagonegro basin, which has been recently proposed as the GSSP candidate for the base of the Rhaetian. These correlations allow us to elucidate the sedimentary dynamics and evolution of the southern Apennine carbonate platform and of the adjoining Lagonegro Basin across the latest Norian to earliest Hettangian time interval. We then perform a high-resolution correlation with the classical Val Adrara/Italcementi quarry section in the Lombardy Basin, and with other reference sections like the base of Hettangian GSSP of Kuhjoch (Austria) and the St Audrie’s Bay section (UK), aiming at interpreting the evolution of the Apennine carbonate platform in the framework of the end-Triassic events. Finally, we attempt using stratigraphic changes in minor and trace elemental concentration, measured with a portable XRF device, to build a high-resolution orbital cyclostratigraphy for the Valle Agricola section. Authors:* Montanaro A.*, Falzoni F., Iannace A. & Parente M.