Late-Quaternary incised valleys and tidal inlets of the northern Adriatic shelf and related alluvial plains

The reconstruction of the past sea-level changes and of their effects on the paleoenvironmental evolution are necessary steps for the modelling of the future sea-level rise and for the elaboration of management plans for the safeguard of the coastal systems. Such reconstruction is often hampered by the scarceness of adequate indicators as a consequence of the lack of formation/preservation or due to the low resolution. This work focuses on the analysis of possible new paleo sea-level indicators. This research is essential in order to provide new data to constrain the marine transgression that took place after the Last Glacial Maximum (LGM) and to understand the consequent environmental evolution. A series of incised landforms that formed and were infilled during this period were therefore analysed. Incised landforms constitute one of the few available archives for the reconstruction of the past and especially for periods of high sea-level rise rate, which are usually characterized by few available paleo sea-level indicators as a consequence of the lack of formation or preservation. The northern Adriatic shelf and the contiguous Venetian-Friulian Plain were chosen for this research due to their peculiar physiography, notably the low gradient of the continental shelf. The northern Adriatic shelf was investigated through a series of high-resolution seismic profiles, allowing to document for the first time the presence of almost 100 paleo tidal inlets. Some of these have been investigated in detail, providing new pieces of evidence for the understanding of the evolution of the area during the early Holocene and the relation between the different rates of sea-level rise and the formation and preservation of lagoon environments. The analysis of a large dataset of cores that sampled the infilling material of an incised valley located in the subsurface of the modern Venetian-Friulian Plain allowed a detailed reconstruction of the environmental evolution in the area since the Late Glacial. In particular, the switch from a fluvial freshwater environment to a brackish lagoon one was recognized and dated to Early Holocene. Finally, this work presents some considerations and possible future developments for the use of such indicators in the reconstruction of timing and modes of the last marine transgression