This study reveals how rare earth elements and yttrium (REY) cycle through an ocean margin system, clarifying the mechanisms that govern benthic REY fluxes and the preservation of Nd isotope compositions (εNd) in authigenic sediment phases.Samples were collected during cruise M182 in 2022. Bulk sediment samples were freeze-dried and ground prior to leaching. Authigenic phases were extracted through a 10s leaching procedure using 0.005 M hydroxylammonium hydrochloride, 1.5% acetic acid, and 0.03 M Na-EDTA buffered to ca. pH 4 with NaOH solution (Huang et al., 2021). For selected samples, data is also provided for a "strong" leach using 0.05 M hydroxylammonium hydrochloride, 15% acetic acid and 0.03 M Na-EDTA buffered to ca. pH 4 with NaOH, that followed after a decarbonation step using 40% acetic acid buffered to pH 4 using Na acetate. The leftover detrital sediment fraction was processed using alkaline fusion. Neodymium was purified using first BIORAD AG50W-X12 resin, followed by Eichrom Ln-spec resin. Samples were measured using a MC-ICP-MS (Thermo Fisher Neptune).