Lake evolution and landscape history in the lower Mincio River valley, unravelling drainage changes in the central Po Plain (N-Italy) since the Bronze Age

The Etruscan harbour of Forcello, in the lower valley of the Mincio River, northern Italy, was active between 540 and 390 BC. The stratigraphic investigations revealed that the settlement occupied a hill on the shore of a lake. The lake sediments and the palaeoecological record, supported by radiocarbon ages, document the basin origin in the Middle Bronze Age as well as the development of aquatic and terrestrial vegetation through the Iron Age and the Roman Age, until the reclamation in the 17th century. The pollen record provides new evidence about the forest cover and the Juglans introduction in the central Po Plain in the early Iron Age. The lake expanded during the early Iron Age, after the diversion of the Po River at Guastalla. Increasing bedload, discharge and sedimentation rates in the Po River system dammed the confluence with the Mincio River, starting the development of the lake. Bronze Age human pressure on forest may also have contributed to this bedload increase. Subsidence related to local tectonics in the axial portion of the river network and rising base-level of the Po Plain fluvial system, induced by increasing sea level, are the triggering factors of these drainage changes in the central Po Plain.