Inter-element associations in some pelagic deposits

Cronan, D. S.

doi:10.1016/0009-2541(69)90025-4

Cited by 27 publications

(10 citation statements)

References 8 publications

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“…The correlation matrix (Table 5) shows a well defined correlation between Fe, Cu, and Ni, and between Mn and Ni. This is in excellent agreement with the inter-element relationships established by Cronan (1969) for pelagic sediments from the Indian and Pacific Oceans, but contrary to the exclusive association of Ni with Mn in deep-sea sediments observed by Carvajal and Landergren (1969). In general, Mn shows an antipathetic relationship to Fe but this is not always well defined.…”

Section: Resultssupporting

confidence: 66%

Influence of manganiferous fragments on the trace element geochemistry of pelagic sediments, North-West Indian Ocean

Glasby¹

1972

New Zealand Journal of Geology and Geophysics

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Trace element analyses of eight carbonate sediment cores from a limited area on the flanks of the Carlsberg Ridge in the North-west Indian Ocean indicate that upward migration of manganese is not a significant process in this pelagic environment. Element migration is not therefore considered to be an important factor in controlling the trace element geochemistry of manganese nodules from this area. The erratic distribution of manganese within the sediment column is attributed to the random inclusion within the sediment of manganese-rich fragments originating from the disintegration of manganese encrustations on the sea Hoor and the subsequent dispersal of these fragments by bottom current activity. There is no evidence for the in situ formation of manganese micronodules within the sediment column in this locality.

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Section: Resultssupporting

confidence: 66%

Influence of manganiferous fragments on the trace element geochemistry of pelagic sediments, North-West Indian Ocean

Glasby¹

1972

New Zealand Journal of Geology and Geophysics

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“…Within ferromanganese crusts, Cu tends to be more strongly associated with the manganese oxide phase (Cronan, 1969;Kumar et al, 1994). The nature of the manganese oxide phases and the mechanism by which such minerals become highly enriched in trace metals is still unclear.…”

Section: Introductionmentioning

confidence: 96%

Surface complexation of Cu on birnessite (δ-MnO2): Controls on Cu in the deep ocean

Sherman

Peacock

2010

Geochimica et Cosmochimica Acta

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Hexagonal birnessite (d-MnO 2 ) is a close analogue to the dominant phase in hydrogenetic marine ferromanganese crusts and nodules. These deposits contain $0.25 wt.% Cu which is believed to be scavenged from the overlying water column where Cu concentrations are near 0.1 lg/L. Here, we measured the sorption of Cu on d-MnO 2 as a function of pH and surface loading. We characterized the nature of the Cu sorption complex at pH 4 and 8 using EXAFS spectroscopy and find that, at pH 4, Cu sorbs to birnessite by inner-sphere complexation on the {0 0 1} surface at sites above Mn vacancies to give a three to fourfold coordinated complex with 6 Mn neighbors at $3.4 Å . At pH 8, however, we find that some Cu has become structurally incorporated into the MnO 2 layer by occupying the vacancy sites to give 6 Mn neighbors at $2.91 Å . Density functional calculations on CuMn 18 O 24 ðOHÞ 30 ðH 2 OÞ 3 À4 and CuMn 18 O 21 ðOHÞ 33 ðH 2 OÞ 3 À1 clusters predict a threefold coordinated surface complex and show that the change from surface complexation to structural incorporation is a response to protonation of oxygens surrounding the vacancy site. Consequently, we propose that the transformation between sorption via surface complex and vacancy site occupancy should be reversible. By fitting the Cu sorption as a function of surface loading and pH to the formation of the observed and predicted surface complex, we developed a surface complexation model (in the basic Stern approximation) for the sorption of Cu onto birnessite. Using this model, we demonstrate that the concentration of inorganic Cu in the deep ocean should be several orders of magnitude lower than the observed total dissolved Cu. We propose that the observed total dissolved Cu concentration in the oceans reflects solubilization of Cu by microbially generated ligands.

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“…In the marine environment, for example, Ni is enriched on the order 10 6 in deep-sea ferromanganese nodules (e.g., Arrhenius, 1963) and numerous chemical and sequential analyses of marine ferromanganese precipitates show a positive Ni-Mn correlation (e.g., chemical analyses of Pacific Ocean ferromanganese nodules (e.g., Goldberg, 1954;Willis and Ahrens, 1962;Cronan, 1969;Calvert and Price, 1977); sequential analyses of Indian and Atlantic Ocean nodules (e.g., Moorby and Cronan, 1981), Pacific nodules and encrustations (e.g., Aplin and Cronan, 1985), and Pacific crusts (e.g., Koschinsky and Halbach, 1995;Koschinsky and Hein, 2003)). The main Mn-bearing phase in marine (e.g., Burns and Burns, 1976) and soil (e.g., Chukhrov and Gorshkov, 1981) ferromanganese precipitates is the phyllomanganate birnessite, often present in a turbostratic form termed vernadite (e.g., Manceau et al, 2007a).…”

Section: Introductionmentioning

confidence: 99%

Physiochemical controls on the crystal-chemistry of Ni in birnessite: Genetic implications for ferromanganese precipitates

Peacock

2009

Geochimica et Cosmochimica Acta

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Inter-element associations in some pelagic deposits

Cited by 27 publications

References 8 publications

Influence of manganiferous fragments on the trace element geochemistry of pelagic sediments, North-West Indian Ocean

Influence of manganiferous fragments on the trace element geochemistry of pelagic sediments, North-West Indian Ocean

Surface complexation of Cu on birnessite (δ-MnO2): Controls on Cu in the deep ocean

Physiochemical controls on the crystal-chemistry of Ni in birnessite: Genetic implications for ferromanganese precipitates

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