Last interglacial global mean sea level from high-precision U-series ages of Bahamian fossil coral reefs

• Published in: Quaternary Science Reviews
• Main Authors: Dumitru, Oana A., Dyer, Blake, Austermann, Jacqueline, Sandstrom, Michael R., Goldstein, Steven L., D'Andrea, William J., Cashman, Miranda, Creel, Roger, Bolge, Louise, Raymo, Maureen E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Quaternary Science Reviews 2023
• Subjects: Last interglacial; U-series ages; The Bahamas; Sea-level changes; Long Island; Crooked Island; Ice Sheet
• Online Access: http://hdl.handle.net/1828/15644; https://doi.org/10.1016/j.quascirev.2023.108287

We thank The Bahamas Environment, Science & Technology Commission and many Bahamian people for support of our field work. TanDEM-X digital elevation data are under copyright by the German Aerospace Center. All rights reserved; used with permission within Project DEM GEOL1210 (A.R./M.E.R.). We also thank Reinhard Kozdon for the resources in the sample preparation laboratory. We acknowledge PALSEA, a working group of the International Union for Quaternary Sciences (INQUA) and Past Global Changes (PAGES), which in turn received support from the Swiss Academy of Sciences and the Chinese Academy of Sciences. Accurate characterization of Last Interglacial (MIS 5e; ∼129–116 ka) sea level is important for understanding ice sheet sensitivity to climate change, with implications for predicting future sea-level rise. Here we present a record of MIS 5e sea level based on high-precision U-series ages of 23 corals with precise elevation measurements from reefs around Crooked Island, Long Cay, Long Island, and Eleuthera, The Bahamas. Rigorous screening criteria identified the most pristine samples, and nearly all samples show a narrow δ234Uinitial range between 143.8 and 151.3‰. We infer global mean sea level (GMSL) from these local observations by correcting them for glacial isostatic adjustment (GIA) and long-term subsidence. For GIA, we consider a range of ice histories and Earth viscosity structures. We identify, via Bayesian inference, the range of isostatic and GMSL histories that are consistent with MIS 5e observations across The Bahamas. When applying an open-system correction to our ages, we find that MIS 5e GMSL likely peaked higher than 1 m, but very unlikely exceeded 2.7 m. Our posterior GMSL is lower than previous estimates, but consistent with recent results of modeling and observations. Additionally, sea level observations at other locations (Seychelles, Western Australia, Yucatan) are only slightly above/within the 95% range of predicted local sea level, i.e., GIA plus GMSL, for our ...