Data report: early Eocene–early Oligocene carbon and oxygen stable isotope data of bulk carbonates, IODP Expedition 390/393 Sites U1557 and U1558, South Atlantic Transect

During International Ocean Discovery Program Expeditions 390C, 395E, 390, and 393 (the South Atlantic Transect), seven sites were drilled on the western flank of the southern Mid-Atlantic Ridge. Among these sites, Sites U1557 and U1558 recovered Eocene and Oligocene sediments. Such sediments will allow a better understanding of how ocean ecosystems, as well as ocean circulation and chemistry, responded to the paleoceanographic and paleoclimatic changes leading to the Eocene–Oligocene transition. In this study, we present early Eocene through early Oligocene carbon and oxygen stable isotope data (δ13C and δ18O) of bulk carbonates from sediment samples collected in Holes U1557B, U1558A, and U1558F. The data show that the western South Atlantic, a relatively understudied region for the Eocene, recorded some global geochemical features, such as the relatively low δ13C and δ18O values typical of hyperthermal events characterizing the onset of the Early Eocene Climatic Optimum and the rapid shift toward high δ18O and δ13C values at the Eocene/Oligocene boundary.