Mid to late holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)

Multiproxy analysis composed of biostratigraphy and pollen analysis allowed reconstructing the palaeoecolo-gical and palaeoenvironmental evolution of the Tirso river coastal plain in Sardinia (NW Mediterranean) in thelast 6 millennia. We demonstrated that interplay between littoral and fluvial processes have significantly con-trolled the environmental evolution of the area and have played a key role in the pattern of historical andprehistorical settlements of this wide portion of western Sardinian coastline. At the end of Neolithic period (ca.6.0 to 5.5 cal. ka BP) the area close to the shoreline was most likely characterized by large coastal lagoonsintermittently connected to the open sea. Such saltwater influence is corroborated by faunal and pollen as-semblages found in the landward portion of the Tirso coastal plain up to 2 km inland from the modern shoreline.Our data robustly document the end of the transgressive trend at ca. 5.5 cal. ka BP, and a dominant fluvialsedimentation since Final Neolithic period. At this time, a progradational trend started, causing the seawardmigration of shoreline and, consequently, of the barrier-lagoon system. The major landscape modificationtracked along the last 6 millennia may also explain the low density of historical and prehistorical remains in theTirso coastal plain, especially if compared to the nearby rocky area of Sinis Peninsula densely inhabited since theNeolithic. Our data further provide new insights into the Relative Sea Level (RSL) evolution in this sector of theMediterranean. In particular, we improved the mid-Holocene RSL record in Sardinia, where only scarce datawere previously available.