OSL Dated Sea-Level for MIS 5e Interglacial in South Carolina, United States

The degree to which the Last Interglacial (Marine Isotope Stage 5e; ~125,000 Before Present) can serve as an analog for future sea-level rise caused by anthropogenic climate change is a matter of great importance. Refining knowledge of factors such as glacio-hydro-isostatic conditions and ice-sheet histories leading up to and since the Last Interglacial will help resolve this question, and well-constrained, well-dated indicators of relative sea level will provide crucial data towards this end. We conducted stratigraphic surveys on several well-exposed outcrops along the Intercoastal Waterway canal near Myrtle Beach, South Carolina, on the East Coast of the United States. In addition to photogrammetry records of the outcrop, optically stimulated luminescence analysis has produced new dates that provide information about sea level history during the Last Interglacial and subsequent interstadials, while also helping to clarify the complex local stratigraphic context, which consists of a series of coastal beach ridges and paleoshorelines left by highstands. The dates are linked to precisely constrained DGPS elevations referenced to the local hydrographic datum, a technique which has not been widely used in the study area. The new data will be preserved as sea-level index points in the format specified by the World Atlas of Last Interglacial Shorelines as part of the WARMCOASTS project and are an especially important contribution since they add additional points in a passive margin area considered to be tectonically stable since the investigated time period.