The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater and archive data

Type Article
Date 2017-05
Language English
Author(s) Tachikawa Kazuyo1, 2, Arsouze Thomas3, 4, Bayon Germain5, Bory Aloys6, Colin Christophe7, Dutay Jean-Claude8, Frank Norbert9, Giraud Xavier1, 2, Gourlan Alexandra T.10, Jeandel Catherine11, Lacan Francois11, Meynadier Laure12, Montagna Paolo13, Piotrowski Alexander M.14, Plancherel Yves15, Puceat Emmanuelle16, Roy-Barman Matthieu8, Waelbroeck Claire8
Affiliation(s) 1 : Aix Marseille Univ, CNRS, IRD, Aix En Provence, France.
2 : Coll France, CEREGE, Aix En Provence, France.
3 : Ecole Polytech, Lab Meteorol Dynam, Palaiseau, France.
4 : Univ Paris Saclay, ENSTA ParisTech, 828 Bd Marechaux, F-91762 Palaiseau, France.
5 : IFREMER, Unite Rech Geosci Marines, F-29280 Plouzane, France.
6 : Univ Lille, CNRS, Univ Littoral Cote dOpale, UMR8187,LOG, F-59000 Lille, France.
7 : Univ Paris Saclay, Univ Paris Sud, Lab Geosci ParisSud GEOPS, F-91405 Orsay, France.
8 : Univ Paris Saclay, CEA CNRS UVSQ, Lab Sci Climat & Environm LSCE PSL, F-91191 Gif Sur Yvette, France.
9 : Heidelberg Univ, Inst Environm Phys, D-69120 Heidelberg, Germany.
10 : Univ Grenoble Alpes, ISTerre, CS 40700, F-38058 Grenoble 9, France.
11 : Univ Toulouse, CNRS, CNES, Observ Midi Pyrenees,IRD,UPS,LEGOS, Toulouse, France.
12 : Univ Paris Diderot, UMR CNRS 7154, Sorbonne Paris Cite, Equipe Geochim Cosmochim,Inst Phys Globe Paris, 1 Rue Jussieu, F-75005 Paris, France.
13 : ISMAR CNR, Via Gobetti 101, I-40129 Bologna, Italy.
14 : Univ Cambridge, Dept Earth Sci, Cambridge, England.
15 : Univ Oxford, Dept Earth Sci, Oxford OK1 3AN, England.
16 : UMR CNRS 6282 Biogeosci, 6 Bd Gabriel, F-21000 Dijon, France.
Source Chemical Geology (0009-2541) (Elsevier Science Bv), 2017-05 , Vol. 457 , P. 131-148
DOI 10.1016/j.chemgeo.2017.03.018
WOS© Times Cited 50
Keyword(s) Nd isotopes, Water mass tracer, Data compilation, Predicted seawater epsilon(Nd), Seawater-archive comparison
Abstract Neodymium isotopic compositions (143Nd/144Nd or εNd) have been used as a tracer of water masses and lithogenic inputs to the ocean. To further evaluate the faithfulness of this tracer, we have updated a global seawater εNd database and combined it with hydrography parameters (temperature, salinity, nutrients and oxygen concentrations), carbon isotopic ratio and radiocarbon of dissolved inorganic carbon. Archive εNd data are also compiled for leachates, foraminiferal tests, deep-sea corals and fish teeth/debris from the Holocene period (< 10,000 years).

At water depths ≥ 1500 m, property-property plots show clear correlations between seawater εNd and the other variables, suggesting that large-scale water mass mixing is a primary control of deepwater εNd distribution. At ≥ 200 m, basin-scale seawater T-S-εNd diagrams demonstrate the isotopic evolution of different water masses. Seawater and archive εNd values are compared using property-property plots and T-S-εNd diagrams. Archive values generally agree with corresponding seawater values although they tend to be at the upper limit in the Pacific. Both positive and negative offsets exist in the northern North Atlantic. Applying multiple regression analysis to deep (≥ 1500 m) seawater data, we established empirical equations that predict the main, large-scale, deepwater εNd trends from hydrography parameters. Large offsets from the predicted values are interpreted as a sign of significant local/regional influence. Dominant continental influence on seawater and archive εNd is observed mainly within 1000 km from the continents. Generally, seawater and archive εNd values form gradual latitudinal trend in the Atlantic and Pacific at depths ≥ 600 m, consistent with the idea that Nd isotopes help distinguish between northern/southern sourced water contributions at intermediate and deep water depths.
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Tachikawa Kazuyo, Arsouze Thomas, Bayon Germain, Bory Aloys, Colin Christophe, Dutay Jean-Claude, Frank Norbert, Giraud Xavier, Gourlan Alexandra T., Jeandel Catherine, Lacan Francois, Meynadier Laure, Montagna Paolo, Piotrowski Alexander M., Plancherel Yves, Puceat Emmanuelle, Roy-Barman Matthieu, Waelbroeck Claire (2017). The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater and archive data. Chemical Geology, 457, 131-148. Publisher's official version : https://doi.org/10.1016/j.chemgeo.2017.03.018 , Open Access version : https://archimer.ifremer.fr/doc/00376/48768/