Middle to early late Eocene benthic foraminiferal oxygen and carbon stable isotopes from ODP Hole 177-1090B@en

Here, we present oxygen and carbon stable isotope data measured on benthic foraminifera from Site 177-1090B. This site is located on the southwest flank of the Agulhas Ridge (sub-Antarctic Atlantic Ocean) and was drilled during the Ocean Drilling Program Leg 177. Benthic foraminifera were picked from the >150 •m fraction and sonified to remove any residual clay prior to stable isotope analyses. Based on preservation and availability, approximately 1 to 12 specimens of benthic foraminifera of the genus Cibicidoides were selected for analysis. When Cibicidoides were not present in the samples considered, 5 to 21 specimens of Nuttallides truempyi or 3 to 12 specimens of Oridorsalis umbonatus were analyzed (34 and 26 samples, respectively, including replicates). In these cases, values were corrected to Cibicidoides using the calibration of Katz et al. (2003, doi:10.1029/2002PA000798). Measurements were conducted at the Stable Isotope Laboratory in the Department of Earth and Planetary Sciences at Rutgers University, using a Micromass Optima mass spectrometer. Stable isotope values are reported versus Vienna Pee Dee Belemnite (V-PDB) by analyzing the standard NBS-19 and an internal laboratory standard. The data set reported here spans the middle and early late Eocene (~42-37 Ma). Sample ages were calculated using an age model based on magnetostratigraphy and calcareous nannoplankton datums (Borrelli et al., 2021; doi:10.1029/2020PA004168) and were reported according to the Geological Time Scale 2012 (Gradstein et al., 2012, doi:10.1016/C2011-1-08249-8).