A new δ13Ccarb curve was obtained from an expanded peritidal succession in western Sicily and was used toinvestigate the relationships between isotopic signatures and biological events on carbonate platforms acrossthe Triassic-Jurassic boundary (TJB). The resulting curve shows two main negative carbon isotopic excursions(CIEs) that fit well with the “Initial” and “Main” CIEs that are recognized worldwide and linked to the End-Triassic Extinction (ETE). In the studied section, the first negative CIE marks the disappearance of the largemegalodontids, which were replaced by small and thin-shelled specimens, while the “Main” CIE correspondsto the last occurrence (LO) of the megalodontids and, approximately 50m upsection, to the total demise of theRhaetian benthic foraminifer community. Upward, the carbon curve shows a positive trend (ca. +1‰) and agradual recovery of the benthic communities after an approximately 10 m-thick barren interval populatedonly by the problematic alga Thaumatoporella parvovesiculifera.A comparison between the Mt. Sparagio δ13Ccarb curve and other coeval Ccarb and Corg curves from carbonateplatform, ramp and deep basin successions indicates similar isotopic trends; however, the diverse magnitudesand responses of benthic communities confirmthat the carbon cycle perturbations have been globally significant,and were influenced by external forces such as CAMP volcanism. The multiphase nature of the extinction pulsescould have been caused by local environmental changes related to transgression/regression phenomena. Overall,this study adds new data and a new timing to the effect of the acidification process on carbon productivity andbenthic communities in different environments across the TJB.
|Numero di pagine||9|
|Stato di pubblicazione||Published - 2018|
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