Middle to late Pleistocene coastal deposits of Alghero, northwest Sardinia (Italy): Chronology and evolution

摘要: The shallow-marine to coastal deposits of Alghero have been dated using the Optically Stimulated Luminescence (OSL) method, and studied define palaeoenvironmental evolution areas in northwest Sardinia. Dating, coupled with sedimentological stratigraphical analyses, allowed subdivision succession four unconformity-bounded units (U2, U3a, U3b, U4). Unit U2 penultimate glacial stage (MIS 6; ca. 150 ka) is composed dune formed intermittently along rocky under strong wind conditions. Subunit U3a cliff-bounded gravelly dominated pocket beach deposits, commonly highly fossiliferous, assigned interglacial MIS 5e (ca. 125 ka). U3b characterized by sandy systems isotopic sub-stage 5c 100 unconformity between U4 marks initiation last regression 5a/4; 77 during which shelf were exposed small incised valleys developed. Along valley flanks, colluvial or sheetflood sediments deposited and, central part thick reddish paleosols formed. Valleys eventually filled aeolian 4–3) indicating persistent inland sand transport. Around Alghero, carbonate-rich dunes preferentially migrated lowstand falling stages when climate relatively cold, vegetation quite open, winds are fairly sediment supply from high.