Late Quaternary meiofaunal assemblages as a key to decipher coastal and delta dynamics from the North Adriatic record

Benthic foraminifera and ostracoda represent excellent proxies to characterize modern and fossil settings, since composition and structure of assemblages reflect a suite of environmental parameters. Nevertheless, the response of each group to coastal dynamics on river-influenced shelves and their record beneath modern coastal plains are poorly investigated. This Ph.D. thesis presents six study cases where modern and fossil assemblages of benthic foraminifera and ostracoda are compared and integrated to obtain a high-resolution palaeoecological characterization of the Po coastal plain late Quaternary sediment succession. Multivariate statistical techniques allowed to discern most of the (palaeo)environmental information inherited by meiofauna. The first study case combines benthic foraminifera and ostracoda from the shallow river-influenced North Adriatic shelf to define depositional environments dependent on the position from the Po Delta. The resulting biofacies are applied to the second study case to test how meiofauna record delta dynamics within a Holocene shallow marine succession of the Po Delta. In the third study case, paleontological, sedimentological and geochemical data reveals distinct facies associations within a three-stage progradation model for the Holocene high-stand succession of the Po Plain along a 70-km stretch of coast. Then, focusing on the last phase of high-stand progradation, benthic foraminifera are tested as tracers of short time-scale autogenic deltaic processes within an expanded prodelta succession. The high resolution obtained inspired the fifth study case, where the palaeoecological record provided by benthic foraminifera and ostracoda within a Pleistocene back-barrier succession of the Po coastal plain is compared. The last study aims to identify biotopes and ecological zones of the Bellocchio Lagoon in order to define environmental drivers on meiofaunal assemblages of the North Adriatic back-barrier settings. This research work emphasizes the importance of integrating benthic foraminifera and ostracoda, since exclusively their combination allows to extract complete (palaeo)environmental information from modern and fossil settings.