ODP Leg 119 Site 738 magnesium isotope and major, trace, and rare-earth element data sets

Ocean Drilling Program (ODP) Leg 119 Site 738 magnesium isotope and major, trace, and rare-earth element data sets (Finalised 8th of December 2025) Magnesium isotope (δ26Mg and δ25Mg) and major, trace, and rare-earth element data for chemically extracted phases (carbonate, reactive, residual, fine) from marine sediments collected from Site 738 on the Kerguelen Plateau. Samples span 18.2 to 27.2 m below seafloor at ~20 cm intervals. This approximates to 33.42 to 34.22 million years before present based on the age model in Bohaty et al. (2012). Please see associated peer-reviewed article for more details. Files: Supplementary Table 1: Element measurements for ODP Site 738 measured using a quadrupole ICP-MS (iCap Qc, Thermo Fisher Scientific, Bremen, Germany) at the Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Supplementary Table 2: Rare-earth and yttrium measurements for ODP Site 738 measured using a quadrupole ICP-MS (iCap Qc, Thermo Fisher Scientific, Bremen, Germany) at the Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Supplementary Table 3: Rare-earth and yttrium measurements normalised to Post-Archean Australian Shale (PAAS; (PAAS; Taylor & McLennan, 1985) for ODP Site 738. Supplementary Table 4: Age model (Bohaty et al., 2012) and magnesium isotope measurements for ODP Site 738 determined by Multi-collector Inductively Coupled Plasma Mass Spectrometer (Neptune, Thermo Fisher Scientific, Bremen, Germany) at the Kochi Institute for Core Sample Research, JAMSTEC (Eom et al., 2022) Format: Age (Ma) = millions of years before present. δ25Mg and δ26Mg = [(25Mg/24Mg)sample / (25Mg/24Mg)DSM−3 – 1] × 1000 and [(26Mg/24Mg)sample / (26Mg/24Mg)DSM−3 – 1] × 1000. Sample = expedition sample designation specifying core number (e.g., 1), type (i.e., H), section number (e.g., 1), section half (i.e., W) and depth range in meters below seafloor. SD = standard deviation. SE = standard error References: Bohaty, S. M., Zachos, J. C., & Delaney, M. L. (2012). Foraminiferal Mg/Ca evidence for southern ocean cooling across the eocene–oligocene transition. Earth and Planetary Science Letters, 317, 251-261. Eom, J., Yoshimura, T., Akizawa, N., Wakaki, S., Ishikawa, T., Takazawa, E.,…Kawahata, H. (2022). The magnesium isotopic compositions of the crust and mantle: A study on the Oman ophiolite. Chemical Geology, 606, 120969. Taylor, S. R., & McLennan, S. M. (1985). The continental crust: its composition and evolution.