Age chronology of mixed planktic foraminifera from sediment core SK237 GC09, northern Indian Ocean

The gravity core (SK237 GC09) was collected from the central equatorial Indian Ocean (12°00.59′N, 70°52.20′E) from a water depth of 3001 m, during the 237th cruise of the ORV Sagar Kanya. The top section of the core was dated by four accelerator mass spectrometer radiocarbon dates on mixed planktic foraminifera, measured at the Center for Applied Isotope Studies, the University of Georgia, USA. The 14C dates were calibrated by using Calib7.0 software and MARINE13 dataset (Stuiver et al., 2018). The chronology of the older section was established by comparing the stable oxygen isotopic (δ18O) ratio of surface-dwelling planktic foraminifera Globigerinoides ruber (white) with the LR04 global isostack (Lisiecki and Raymo, 2005). The elemental (Mg/Ca) and stable oxygen isotopic (δ18O) ratio of surface-dwelling planktic foraminifera Globigerinoides ruber (white) was analyzed to reconstruct SST and evaporation-precipitation changes.