This dataset contains geochemical and analytical quality-control data generated for planktonic foraminifera Orbulina universa from IODP Expedition 361 Site U1476 in the Mozambique Channel, western Indian Ocean. The dataset supports the evaluation of O. universa geochemistry as an archive of past seawater pH, atmospheric CO₂, and paleoceanographic variability over glacial–interglacial to million-year timescales.solution-based geochemical dataset obtained from O. universa shells, including both screened and unscreened data. The measured parameters include B/Ca, δ¹¹B, δ¹³C, δ¹⁸O, Mg/Ca, Al/Ca, Sr/Ca, Ba/Ca, and ⁸⁷Sr/⁸⁶Sr, together with associated sample metadata and screening information. These data were used to assess contamination, shell-size-dependent effects, glacial–interglacial variability, and the relationship between δ¹¹B-derived seawater pCO₂ and atmospheric CO₂.