Decoding the interplay between tidal notch geometry and sea-level variability during the Last Interglacial (Marine Isotopic Stage 5e) high stand

Relic coastal landforms (fossil corals, cemented intertidal deposits, or erosive features carved onto rock coasts) serve as sea-level index points (SLIPs) widely used to reconstruct past sea-level changes. Traditional SLIP-based sea-level reconstructions face challenges in capturing continuous sea-level variability and dating erosional outcrops, such as ubiquitous tidal notches, carved around tidal level on carbonate cliffs. We propose a novel approach to such challenges by using a numerical cliff erosion model embedded within a Monte-Carlo simulation to investigate the most likely sea-level scenarios responsible for shaping one of the best-preserved tidal notches of the Last Interglacial age in Sardinia, Italy. Results align with Glacial Isostatic Adjustment model predictions, indicating that synchronized or out-of-sync ice-volume shifts in Antarctic and Greenland ice sheets can reproduce the notch morphology, with sea level confidently peaking at 6m. This new approach yields continuous sea-level insights, bridging gaps in traditional methods and illuminating past Interglacial sea-level dynamics.