The flooding at the end of Messinan salinity crisis fact or fiction?

This thesis investigates the termination of the Messinian Salinity Crisis (MSC) and the associated environmental evolution in the northern Mediterranean basin, with a particular focus on the Northern Apennines. A multidisciplinary approach is adopted, integrating lipid biomarkers, micropaleontology, magnetostratigraphy, and advanced multivariate statistical methods to establish a coherent and quantitative framework for the Messinian–Zanclean transition. The first part reconstructs sea surface temperatures (SST) during the Miocene– Pliocene transition using long-chain alkenones (LCA) combined with stable isotope analyses of calcareous microfossils. The results reveal a gradual return to marine conditions, challenging the hypothesis of a catastrophic flooding event. The second part addresses paleoenvironmental variability by analyzing an extensive dataset of biomarkers (including GDGTs, alkenones, and n-alkanes) supported by advanced multivariate statistical techniques. The use of collinearity analysis, cluster analysis, and redundancy analysis has corroborated the entire data framework, highlighting the dynamic interplay between terrestrial and marine inputs driven by both regional and global climatic and hydrological factors. The third part of the study focuses on the Pollenzo section (Piedmont Basin), where high-resolution magnetostratigraphic and micropaleontological data refine the chronological model of the transition. The findings support a model of gradual marine transgression, with open marine conditions being restored in northern Mediterranean progressively between 5.33 and 5.23 Ma. Overall, the thesis presents a unified interpretation of the MSC termination, emphasizing the importance of an integrated, multiproxy approach constrained and enhanced by multivariate statistics in deciphering complex geological events and significantly contributing to the debate on the nature and timing of the end of the messinian salinity crisis and the restauration of normal marine condition troughout the mediterranean basin.