Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific

IntroductionCobalt is the most important critical element in ferromanganese crusts. Co concentration in the Fe-Mn crusts is one of the key parameters for determination of the Co resource. Thus, it is essential to clarify the controls on the variations of Co concentration of ferromanganese crusts.Met...

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Main Authors: Xiangwen Ren, James R. Hein, Zanzhong Yang, Na Xing, Aimei Zhu
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-12-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2024.1489943/full
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author Xiangwen Ren
Xiangwen Ren
James R. Hein
Zanzhong Yang
Na Xing
Aimei Zhu
author_facet Xiangwen Ren
Xiangwen Ren
James R. Hein
Zanzhong Yang
Na Xing
Aimei Zhu
author_sort Xiangwen Ren
collection DOAJ
description IntroductionCobalt is the most important critical element in ferromanganese crusts. Co concentration in the Fe-Mn crusts is one of the key parameters for determination of the Co resource. Thus, it is essential to clarify the controls on the variations of Co concentration of ferromanganese crusts.MethodsTo clarify the controls on Co concentration of hydrogenetic nonphosphatized ferromanganese crusts, an equation was deduced based on Fick’s First Law: Co(%)=Mn02(%)·Dsw·cswδ·zGR·Ssp, and eight potential controls were gleaned from this equation, including dilution, diffusivity of Co ions in seawater (Dsw), temperature which controls the Dsw, Co ion concentration in seawater (Csw), the diffusion distance of Co ions near the interface of seawater and Fe-Mn crusts (δ), thickness of one molecular layer (z), growth rate (GR), and specific surface area of Fe-Mn crusts (Ssp). To constrain the value of Co ion diffusion gradients (Csw¯/δ) and consequently verify the proposed equation, we determined the Co concentrations, growth rates, and specific surface area of the outermost layer of Fe-Mn crusts, and calculated diffusivity of Co2+.ResultsThe Csw¯/δ for the Fe-Mn crusts from Caiwei seamount (Magellan seamounts) was determined to be 295-496 pM/mm, which are reasonable for the Co ion concentrations and seawater mixing in the deep ocean.DiscussionAccording to the equation established in this study, the trend of decreasing Co concentrations in Fe-Mn crusts with increasing water depth is controlled mainly by dilution and to a lesser extent by seawater Co ion concentration, temperature of seawater, and consequently the diffusivity of Co ions in seawater.
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spelling doaj-art-a9b74e86fdb24df687eba30f154ae1f52024-12-19T11:44:08ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-12-011110.3389/fmars.2024.14899431489943Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west PacificXiangwen Ren0Xiangwen Ren1James R. Hein2Zanzhong Yang3Na Xing4Aimei Zhu5Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, ChinaLaboratory for Marine Geology, Laoshan Laboratory, Qingdao, ChinaRetired, Soquel, CA, United StatesSchool of Materials Science and Engineering, Shandong University of Technology, Zibo, Shandong, ChinaLab of Isotope Marine Chemistry, Xiamen University, Xiamen, Fujian, ChinaKey Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, ChinaIntroductionCobalt is the most important critical element in ferromanganese crusts. Co concentration in the Fe-Mn crusts is one of the key parameters for determination of the Co resource. Thus, it is essential to clarify the controls on the variations of Co concentration of ferromanganese crusts.MethodsTo clarify the controls on Co concentration of hydrogenetic nonphosphatized ferromanganese crusts, an equation was deduced based on Fick’s First Law: Co(%)=Mn02(%)·Dsw·cswδ·zGR·Ssp, and eight potential controls were gleaned from this equation, including dilution, diffusivity of Co ions in seawater (Dsw), temperature which controls the Dsw, Co ion concentration in seawater (Csw), the diffusion distance of Co ions near the interface of seawater and Fe-Mn crusts (δ), thickness of one molecular layer (z), growth rate (GR), and specific surface area of Fe-Mn crusts (Ssp). To constrain the value of Co ion diffusion gradients (Csw¯/δ) and consequently verify the proposed equation, we determined the Co concentrations, growth rates, and specific surface area of the outermost layer of Fe-Mn crusts, and calculated diffusivity of Co2+.ResultsThe Csw¯/δ for the Fe-Mn crusts from Caiwei seamount (Magellan seamounts) was determined to be 295-496 pM/mm, which are reasonable for the Co ion concentrations and seawater mixing in the deep ocean.DiscussionAccording to the equation established in this study, the trend of decreasing Co concentrations in Fe-Mn crusts with increasing water depth is controlled mainly by dilution and to a lesser extent by seawater Co ion concentration, temperature of seawater, and consequently the diffusivity of Co ions in seawater.https://www.frontiersin.org/articles/10.3389/fmars.2024.1489943/fullferromanganese crustsMagellan seamountscobaltdiffusivityPacific
spellingShingle Xiangwen Ren
Xiangwen Ren
James R. Hein
Zanzhong Yang
Na Xing
Aimei Zhu
Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
Frontiers in Marine Science
ferromanganese crusts
Magellan seamounts
cobalt
diffusivity
Pacific
title Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
title_full Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
title_fullStr Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
title_full_unstemmed Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
title_short Controls on cobalt concentrations in ferromanganese crusts from the Magellan seamounts, west Pacific
title_sort controls on cobalt concentrations in ferromanganese crusts from the magellan seamounts west pacific
topic ferromanganese crusts
Magellan seamounts
cobalt
diffusivity
Pacific
url https://www.frontiersin.org/articles/10.3389/fmars.2024.1489943/full
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