Upper Pleistocene Marine Levels of the Es Copinar–Es Estufadors (Formentera, Balearic Islands, West Mediterranean)

Late Pleistocene coastal deposits on the southeastern coast of Formentera (Es Ram–Es Estufadors) provide a high-resolution record of sea-level and climatic fluctuations associated with Marine Isotope Stage (MIS) 5. Three distinct beach levels (Sef-1, Sef-2, Sef-3) were identified, corresponding to substages MIS 5e, 5c, and possibly 5a, based on sedimentological features, fossil assemblages, and Optically Stimulated Luminescence (OSL) dating. The oldest beach level (Sef-1) is attributed to MIS 5e (ca. 128–116 ka) and is characterised by the widespread presence of thermophilic Senegalese fauna—including <i>Thetystrombus latus</i>, <i>Conus ermineus</i>, and <i>Linatella caudata</i>—which mark the onset of this interglacial phase and are associated with two peaks in relative sea-level highstand. A subsequent cooling event during MIS 5d is recorded by the development of thin palaeosols and the disappearance of these warm-water taxa. The second beach level (Sef-2) reflects renewed sea-level rise and warmer conditions during MIS 5c, with abundant macrofauna and red algae. The transition to MIS 5b (~97 ka) is marked by a significant sea-level drop (down to –60 m), cooler climate, and enhanced colluvial sedimentation linked to increased runoff and erosion. In total, 54 macrofaunal species were identified—16 from Sef-1 and 46 from Sef-2—highlighting ecological shifts across substages. These results improve our understanding of coastal response to sea-level oscillations and paleoenvironmental dynamics in the western Mediterranean during the Late Pleistocene.