Effects of Past Nd Seawater Concentrations on Nd-Isotope Paleocirculation Reconstructions: A Bayesian Approach

• Main Authors: Yehudai, M, Tweed, LE, Ridge, S, Wu, Y, Goldstein, SL
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2023
• Subjects: 3709 Physical Geography and Environmental Geoscience; 37 Earth Sciences; 3703 Geochemistry; 3705 Geology; 3706 Geophysics; 14 Life Below Water; Antarctic; Pacific; Antarc*
• Online Access: https://www.repository.cam.ac.uk/handle/1810/358703

Publication status: Published Funder: Storke Endowment of the Department of Earth and Environmental Sciences, Columbia University <jats:title>Abstract</jats:title><jats:p>Neodymium (Nd) isotope ratios are potentially valuable for paleo‐ocean circulation reconstructions because they trace water‐mass transport and mixing in the present‐day oceans. Moreover, the Atlantic and Pacific global end‐member Nd‐isotope values can be constrained through time, and at in‐between sites their proportions vary with past climate changes. However, an important source of uncertainty about Nd‐isotopes' applicability for paleo‐circulation studies arises from the inability to constrain past Nd‐concentrations of the end‐members. Here we address this “paleo‐[Nd] problem” through a Bayesian analysis. Results show that even large variability in end‐member Nd‐concentrations over the Pleistocene is unlikely to significantly impact their concentration ratio, therefore end‐member concentration changes likely have only small impacts on Nd‐isotope ratios at in‐between locations. The results support their applicability to reconstruct past Atlantic paleo‐circulation. In addition, a Nd‐isotope mass balance for Antarctic Bottom Water shows that its present‐day Nd‐isotope values are consistent with the input from its sources.</jats:p>