Morphological evolution of Lèsina lagoon (southern Adriatic, Italy)

The Late Quaternary geomorphological evolution of Lèsina lagoon is highlighted through morphological surveys, both of the emerged and underwater landscape of the basin. The genesis of this transitional environment is linked to littoral dynamics that led to progressive development of composite littoral spits inside a shallow-water marine bay, characterised by inherited morphostructures bordered by high morphological reliefs. During the post-glacial age, the bay was gradually filled with clasts drifted out from the close Fortore River mouth, very likely after the Holocene climatic optimum. The growth of a steady littoral sandy ridge, first NW-SE then W-E oriented, on wich dunes developed, led to the genesis of a primitive lagoon. Subsequently, the lagoon shape changed because of constant sediment filling and the lagoon depth and channels decreased. Thin peat levels alternating with marine sandy-silty sediments, suggest that marine and marshy stages alternated during the lagoon system evolution.