Surface geologic constraints on Pleistocene history and relative sea level with a focus on Last Interglacial deposits, San Salvador Island, Bahamas

San Salvador Island, along the eastern margin of the Bahamas−Caicos Archipelago, is a key locality for reconstructing Pleistocene carbonate stratigraphy and Last Interglacial (marine isotope stage [MIS] 5e, 129−116 ka) sea-level history. A high-resolution dataset, including airborne light detection and ranging (LiDAR) data, drone photogrammetry, differential global positioning system (GPS), petrography, field mapping, and a 44 core database, establishes a refined stratigraphic framework and geologic history. This framework identifies interglacial deposits from MIS 11, MIS 9, MIS 5e (subdivided into MIS 5e_1 and MIS 5e_2a−e), MIS 5a, and MIS 1. MIS 11 and MIS 9 units are constrained by superposition and paleoelevation relative to established sea-level stands. MIS 5e is the most extensively exposed and stratigraphically significant interval for interpreting former sea level across the Bahamas−Caicos Archipelago. Early MIS 5e deposition is represented by the lower Cockburn Town reef (“reef I”; 129−125 ka) at <1 m relative sea level (RSL) prior to intra−MIS 5e erosion. Upper MIS 5e_2 subunits record transgression and highstand variability. Subunits MIS 5e_2a−c consist of composite parabolic dune ridges and associated lagoonal, tidal-flat, tidal-channel, and strand-plain facies formed at +3 m RSL. MIS 5e_2d consists of shingled dune sheets indicating increasing aridity during RSL rise to +7 m. MIS 5e_2e deposition forms down-stepping strand plains initiating at +8 m and descending below present sea level, recording late-stage sea-level fall. Final MIS 5e reef development (“reef II”; 122−119 ka) includes patch reefs localized along headlands at +1 m to +3 m RSL. This revised stratigraphy refines Last Interglacial sea-level dynamics and models carbonate-platform response to rapid climate change.