SEDIMENTATION OF RIVERBORNE MATERIAL IN A SHALLOW SHELF SEA - ADIGE RIVER, ADRIATIC SEA

Suspended matter and bottom sediments at the Adige River mouth have been investigated with the aim of elucidating the sedimentation pattern of riverine suspended matter in the shallow, low-energy, marginal Adriatic Sea. The grain-size distribution and the mineralogical and geochemical composition of samples collected in two different hydrological situations (low and high river discharge) indicate a similar and consistent sedimentary pattern. Fast sedimentation of fine-grained riverborne suspended matter occurs in the prodelta zone due to deceleration of river flow and spreading into the low-energy environment in front of the river mouth; this is probably associated with flocculation processes in brackish waters. Most of the anthropogenically generated substances associated with the particulate phase accumulate in a restricted area at the Adige River mouth. Knowledge of the area directly influenced by the deposition of riverborne suspended matter is of great interest in assessing the capacity of the Northern Adriatic Sea to assimilate anthropogenically generated material.