FN Archimer Export Format
PT J
TI Light Zn and Cu isotope compositions recorded in ferromanganese crusts during the Cenozoic as evidence for hydrothermal inputs in South Pacific deep seawater
BT 
AF Gueguen, Bleuenn
   Rouxel, Olivier
   Fouquet, Yves
AS 1:1,2;2:3;3:3;
FF 1:;2:PDG-REM-GEOOCEAN;3:PDG-REM-GEOOCEAN-CYBER;
C1 Univ Brest, CNRS, UMS 3113, IUEM, Place Nicolas Copernic, 29280 Plouzane, France
   Univ Brest, CNRS, UMR 6538, Geo-Ocean UMR 6538, IUEM, Place Nicolas Copernic, 29280 Plouzane, France
   IFREMER, Centre de Brest, Geo-Ocean UMR 6538, F-29280 Plouzane, France
C2 UBO, FRANCE
   UBO, FRANCE
   IFREMER, FRANCE
SI BREST
SE PDG-REM-GEOOCEAN
   PDG-REM-GEOOCEAN-CYBER
UM GEO-OCEAN
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
   copubli-univ-france
IF 5
TC 3
UR https://archimer.ifremer.fr/doc/00785/89731/104032.pdf
LA English
DT Article
CR ZEPOLYF2
BO L'Atalante
DE ;Ferromanganese crusts;Copper isotopes;Zinc isotopes;hydrothermal inputs
AB This study presents a high-resolution record of Cu and Zn isotopes in four Fe-Mn crusts from the North and South Pacific oceans. North Pacific crusts were collected on the Apuupuu seamount south of the Hawaiian archipelago and South Pacific crusts were recovered near Rurutu Island in the Tahiti archipelago. Major and trace element compositions suggest that Cu and Zn in these crusts is of hydrogenous origin, i.e., precipitated from seawater, and they may therefore mirror deep seawater metal isotope. We show that Cu and Zn display different isotopic patterns between the North and the South Pacific Oceans but show similar temporal evolution within each geographical area. Copper and Zn isotope composition of both North Pacific crusts vary between 0.57 ‰ to 0.73 ‰ for δ65/63CuNIST976 and 0.97 ‰ to 1.25 ‰ for δ66/64ZnJMC-Lyon. In contrast, South Pacific crusts show resolvable temporal variations, with Cu and Zn isotopic ratios increasing sharply over the last ∼ 6 Ma from 0.16 ‰ to 0.51 ‰ and 0.67 ‰ to 1.09 ‰ respectively. Notably, we observed a positive correlation between δ65/63CuNIST976 and δ66/64ZnJMC-Lyon values in Fe-Mn crusts from the South Pacific. The correlation suggests mixing between two components in Fe-Mn crusts, a hydrothermal component with δ65/63CuNIST976 ∼ 0.2 ‰ and δ66/64ZnJMC-Lyon ∼ 0.7 ‰, and a Pacific deep seawater component with δ65/63CuNIST976 ∼ 0.7 ‰ and δ66/64ZnJMC-Lyon ∼ 1.2 ‰. These values are fractionated from modern dissolved Cu and Zn by a factor of −0.3 ‰ and 0.5 ‰ respectively. We suggest that the deep Southern Pacific Ocean received sustained hydrothermal input during the last 6 Ma, which was recorded in the Cu and Zn isotope composition of Fe-Mn crusts precipitated thousands of kilometers away. Our study highlights that hydrothermal venting may be a significant source of Cu and Zn in the deep oceans despite their extensive precipitation within hydrothermal vent fields. We show that this source could be persistent through time, and thus, it could have a significant impact on the biogeochemical cycling of Cu and Zn in seawater which would ultimately be recorded by Fe-Mn crusts. 
PY 2022
PD SEP
SO Geochimica Et Cosmochimica Acta
SN 0016-7037
PU Elsevier BV
VL 333
UT 000886461000001
BP 136
EP 152
DI 10.1016/j.gca.2022.06.038
ID 89731
ER

EF