Bulk calcium carbonate record at IODP Site U1475 during the early Pliocene

This dataset provides a detailed record of early Pliocene calcium carbonate (CaCO3) weight percent from Site U1475, located on the southwestern Agulhas Plateau in the Indian Ocean, obtained during IODP Expedition 361 (South African Climate, January 30–March 31, 2016). A total of 249 sediment samples were analyzed, with each sample prepared by drying for at least 24 hours at 50°C, followed by grinding and additional drying to ensure consistency. CaCO3 content was measured using a UIC Inc. model 5011 CO2 coulometer. Dried, powdered sediment samples (10–18 mg) were weighed on a microbalance and reacted with 2 M HCl, releasing CO2 gas assumed to be entirely derived from CaCO3. The resulting CO2 was titrated, with the endpoint detected by a photodetector. Total inorganic carbon (TIC) was recorded in mg C, and CaCO3 weight percent was calculated using the formula: CaCO3 wt. % = TIC (µg C) × 8.33/sample mass (µg). Quality control included replicates run after every five samples and a 100% CaCO3 standard every ten measurements to detect any instrument drift.