Multiproxy investigation of a Holocene sedimentary sequence near Ferrara (Italy): clues on the physiographic evolution of the eastern Padanian Plain

Purpose This paper investigates soils and sediments from the eastern Padanian Plain (northern Italy) in order to delineate the physiographic evolution of the area. Materials and methods We present new geochemical, mineralogical and textural analyses of alluvial sediments collected from a 13 m deep section located a few kilometers south of Ferrara. The chronology of the related depositional events is provided presenting 14C datings performed on tree trunks buried at depths of ca 9 m and on organic matter from the underlying horizons. Results and discussion The obtained data indicate that 1) the upper part of the sequence (down to depths of 9 m) includes sediments characterized by low nickel-chromium (Ni-Cr) concentrations ascribed to the alluvial deposits of River Reno, deposited in the last 400 years; 2) buried soils (depths 9-10.5 m) developed on Ni-Cr rich sediments related to the River Po; 3) the deeper facies (depths 10.5-13 m) are CaCO3-free and characterized by higher amounts of organic carbon, sulphur and arsenic, reflecting episodic lacustrine/marsh environments; these wetlands plausibly developed in the area during the Iron and Roman ages, persisting up to the Middle age. Conclusions The presented data provide a contribution to understanding the river network evolution during the last 3000 years, and provides insights on the related paleo-hydrological framework that can be useful for geographical and historical reconstructions of the area. Results highlight the importance of investigation of alluvial sediments to elucidate 1) fluctuations of environmental conditions, and 2) anthropogenic impacts on the natural landscape. The study-approach has to be considered valid and applicable even beyond the local framework and contributes to highlighting changes at regional scale.