TY - JOUR
T1 - Rare earth elements and yttrium (REY) variability with water depth in hydrogenetic ferromanganese crusts
AU - Azami, K.
AU - Hirano, N.
AU - Machida, S.
AU - Yasukawa, K.
AU - Kato, Y.
N1 - Funding Information:
The crew and scientific party of the R/V Kairei KR04-08 cruise, R/V Yokosuka YK05-06 and YK10-05 cruises, and the submersible SHINKAI 6500 are thanked for collecting samples. We thank Dr. K. Nakamura, the University of Tokyo, for helping with our analysis. This study was funded in part by the Toray Science and Technology Grant ( 11-5208 ), the Japan Society for the Promotion of Science ( JP17K5715 ), and the Next-generation for ocean resoures exploration of Cross-ministerial Strategic Innovation Promotion Program (SIP).
Funding Information:
The crew and scientific party of the R/V Kairei KR04-08 cruise, R/V Yokosuka YK05-06 and YK10-05 cruises, and the submersible SHINKAI 6500 are thanked for collecting samples. We thank Dr. K. Nakamura, the University of Tokyo, for helping with our analysis. This study was funded in part by the Toray Science and Technology Grant (11-5208), the Japan Society for the Promotion of Science (JP17K5715), and the Next-generation for ocean resoures exploration of Cross-ministerial Strategic Innovation Promotion Program (SIP).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/8/20
Y1 - 2018/8/20
N2 - The origins of ferromanganese (Fe–Mn) crusts that form in seawater and elemental partitioning into these crusts have previously been studied using samples from water depths shallower than 4 km. Here we report geochemical analyses of Fe–Mn crusts sampled from petit-spot volcanoes within the Pacific Ocean at water depths of 5.2–6.0 km. The Fe–Mn crusts have low Mn/Fe ratios (0.63–1.5), high contents of Co, Ni, and rare earth elements and Y (REY), and positive Ce anomalies, indicating a hydrogenetic origin. The Fe–Mn crusts are characterized by lower shale-normalized La/Pr ratios (LaSN/PrSN) than typical hydrogenetic Fe–Mn crusts from the Pacific Ocean. Despite negative LaSN/PrSN and NdSN/SmSN and positive EuSN/GdSN and DySN/HoSN correlations with water depth, the distribution coefficients of the REY are constant. This indicates that the observed REY variability with water depth in these hydrogenetic Fe–Mn crusts reflects that of seawater. In particular, a strong correlation between LaSN/PrSN and water depth has potential for use as a (paleo)ocean hydro-barometer. The variety of REY compositions of Fe–Mn crusts should be interpreted on the basis of distribution coefficients calculated for each water depth.
AB - The origins of ferromanganese (Fe–Mn) crusts that form in seawater and elemental partitioning into these crusts have previously been studied using samples from water depths shallower than 4 km. Here we report geochemical analyses of Fe–Mn crusts sampled from petit-spot volcanoes within the Pacific Ocean at water depths of 5.2–6.0 km. The Fe–Mn crusts have low Mn/Fe ratios (0.63–1.5), high contents of Co, Ni, and rare earth elements and Y (REY), and positive Ce anomalies, indicating a hydrogenetic origin. The Fe–Mn crusts are characterized by lower shale-normalized La/Pr ratios (LaSN/PrSN) than typical hydrogenetic Fe–Mn crusts from the Pacific Ocean. Despite negative LaSN/PrSN and NdSN/SmSN and positive EuSN/GdSN and DySN/HoSN correlations with water depth, the distribution coefficients of the REY are constant. This indicates that the observed REY variability with water depth in these hydrogenetic Fe–Mn crusts reflects that of seawater. In particular, a strong correlation between LaSN/PrSN and water depth has potential for use as a (paleo)ocean hydro-barometer. The variety of REY compositions of Fe–Mn crusts should be interpreted on the basis of distribution coefficients calculated for each water depth.
KW - Ferromanganese crusts
KW - Pacific Ocean
KW - Petit-spot volcanoes
KW - Rare earth elements
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U2 - 10.1016/j.chemgeo.2018.05.045
DO - 10.1016/j.chemgeo.2018.05.045
M3 - Article
AN - SCOPUS:85049304648
SN - 0009-2541
VL - 493
SP - 224
EP - 233
JO - Chemical Geology
JF - Chemical Geology
ER -