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. Mg/Ca and Ba/Ca depth-profile data measured by laser-ablation ICP-MS on O. universa shells from five time intervals: 0.007 Ma, 2.388 Ma, 3.390 Ma, 4.563 Ma, and 6.779 Ma. These profiles were used to examine intra-shell trace-element variability and long-term changes in shell formation and magnesium incorporation.