Factors controlling the chemical composition of marine manganese nodules and crusts: a review and synthesis

Takematsu, Noburu; Satō, Yoshio; Okabe, Shiro

doi:10.1016/0304-4203(89)90063-7

Cited by 37 publications

(18 citation statements)

References 76 publications

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“…Its PAAS-normalized REY pattern precludes, together with the enrichment in Ni and Cu, a hydrothermal origin (Usui et al, 1997;Dekov et al, 2003). In contrast, in particular the positive Ce anomaly is rather indicative for hydrogenetic Mn nodules (Usui et al, 1997 (Dymond et al, 1984;Takematsu et al, 1989). The Mn/Fe ratio of our surface nodule of 4.3 falls within this range.…”

Section: Origin Of the Authigenic Componentsmentioning

confidence: 59%

Characterization of metalliferous sediment from a low-temperature hydrothermal environment on the Eastern Flank of the East Pacific Rise

et al. 2008

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Metalliferous deposits are described from the eastern flank of the East Pacific Rise (EPR) offshore Costa Rica, close to a basaltic seamount called "Dorado high".Based on heat-flow data and porewater profiles, the site is an area of active low temperature hydrothermal discharge. We focus on the mineralogical and chemical analyses from a 124 cm long gravity core (GC50), located on the north-western slope of the 100 m high Dorado high. In this core, the sediments consist of detrital clay minerals as well as authigenic minerals such as zeolites, apatites, and Fe/Mn-rich oxyhydroxides. In contrast, the reference sediments from adjacent areas without hydrothermal activity are olive gray hemipelagic muds composed of volcanic glass particles, clay minerals, siliceous microfossils, and some detrital quartz and feldspar.Bulk sediment chemistry and chemical enrichment factors calculated with respect to the reference sediment indicate that the most important chemical changes occurred at the base of the core from 100 to 124 cm bsf, with strong enrichments in MnO, CaO, P 2 O 5 , and Fe 2 O 3 . These enrichments are correlated with the occurrence of authigenic Fe-oxyhydroxide (goethite) and Mn oxide (todorokite and vernadite, at 100 cm bsf), and hydrothermal apatite (110-124 cm bsf). In the upper section of the core from 12 to 70 cm, the sediment is composed of abundant smectite and authigenic phillipsite, and only minor chemical changes can be observed with respect to the reference sediments.The ubiquitous presence of phillipsite suggests that the entire sedimentary column of core GC50 was first affected by diagenesis. However, below 70 cm bsf, these phillipsites are partially dissolved and Fe oxides occur from 110 to 124 cm, followed 2 upward by Mn oxides at 100 cm. This transition from Fe to Mn rich sediments can be interpreted in terms of an upward increasing redox potential. PAAS-normalized REE patterns of GC50 sediments present clearly negative Ce and positive Y anomalies inherited from seawater at the base of core GC50. These anomalies decrease upward, which we interpret together with the transition from Fe to Mn-rich sediments by an upward migrating low temperature hydrothermal fluid. Thus, after a first stage of diagenesis, the discharge of a low temperature hydrothermal fluid occurred through the sedimentary column, leading to the precipitation of hydrothermal compounds that are lacking towards the surface.

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Section: Origin Of the Authigenic Componentsmentioning

confidence: 59%

Characterization of metalliferous sediment from a low-temperature hydrothermal environment on the Eastern Flank of the East Pacific Rise

et al. 2008

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“…Although this agrees with Marino et al [19], who suggest that cuspate textures grow faster and are depleted in Mn and Co relative to the pillared sections, we propose that the oxide layers probably grow at similar rates, but the foraminifera accumulate quickly relative to a similar thickness of FeMn, increasing the overall crust thickness but not the thickness of the oxides themselves. Smaller variations in the Fe/Mn ratio in areas of relatively low Ca areas are commonly observed as a result of environmental variations in water chemistry, dust input, and bottom currents [30].…”

Section: Textural Variation Detrital Input and Deposit Gradementioning

confidence: 99%

“…Smaller variations in the Fe/Mn ratio in areas of relatively low Ca areas are commonly observed as a result of environmental variations in water chemistry, dust input, and bottom currents [30].…”

Section: In Areas Of Uniformmentioning

confidence: 99%

Assessment of the Mineral Resource Potential of Atlantic Ferromanganese Crusts Based on Their Growth History, Microstructure, and Texture

et al. 2018

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Abstract:The decarbonisation of our energy supply is reliant on new technologies that are raw material intensive and will require a significant increase in the production of metals to sustain them. Ferromanganese (FeMn) crusts are seafloor precipitates, enriched in metals such as cobalt and tellurium, both of which have a predicted future demand above current production rates. In this study, we investigate the texture and composition of FeMn crusts on Tropic Seamount, a typical Atlantic guyot off the coast of western Africa, as a basis for assessing the future mineral resource potential of Atlantic Seamounts. The majority of the summit is flat and covered by FeMn crusts with average thicknesses of 3-4 cm. The crusts are characterized by two dominant textures consisting of either massive pillared growth or more chaotic, cuspate sections of FeMn oxides, with an increased proportion of detrital and organic material. The Fe, Mn, and Co contents in the FeMn oxide layers are not affected by texture. However, detrital material and bioclasts can form about 50% of cuspate areas, and the dilution effect of this entrained material considerably reduces the Fe, Mn, and Co concentrations if the bulk samples are analyzed. Whilst Tropic Seamount meets many of the prerequisites for a crust mining area, the thickness of the crusts and their average metal composition means extraction is unlikely to be viable in the near future. The ability to exploit more difficult terrains or multiple, closely spaced edifices would make economic feasibility more likely.

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“…Removal mechanisms of elements from the ocean have been discussed by many researchers [1][2][3][4][5][6][7][8][9]. It was suggested that the partition of elements between particulate solid phases (pelagic clays, manganese and iron oxides, organisms, etc.)…”

Section: Introductionmentioning

confidence: 99%

Study of Removal Mechanisms of Metal Elements From Seawater Using Radioactive Multitracers

et al. 1991

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The adsorption of metal elements on hydrated ferric oxide, clay minerals, and marine sediments from artificial seawater is studied using radioactive multitracers produced by RIKEN Ring Cyclotron. Removal mechanisms of elements from the ocean have been discussed by many researchers [1][2][3][4][5][6][7][8][9]. It was suggested that the partition of elements between particulate solid phases (pelagic clays, manganese and iron oxides, organisms, etc.) and seawater is, for the first approximation, controlled by the affinity of cations and oxyanions for the hydrolyzed particulate surfaces [2,9]. Adsorption of metal elements on hydrated ferric oxide, clay minerals (montmorillonite and kaolinite), and marine sediments (deep-sea and nearshore sediments) from artificial seawater is studied by a radioactive multitracer method. On the basis of the distribution coefficients of metal elements for the particulates, the ultimate removal mechanism of metal elements from seawater is discussed. MATERIALS AND METHODSAdsorbents Hydrated ferric oxide was prepared by hyrolyzing ferric ions at pH 7.5. Deep-sea and nearshore sediments were obtained from the Penrhyn Basin (12°26.44'S, 157°57.2(YW, depth 5351 meters) and Suruga Bay (34°44.52'N,169° 27.05'E, depth ca. 600 meters), respectively. The adsorbents were stored in artificial seawater as a suspension (2 mg cm'3). Multitracer The multitracers were separated from gold and copper foils irradiated with a 14N beam of 135 McV/nucleon accelerated by the RIKEN Ring Cyclotron in a earner-and salt-free state [10]. The multitracers were shed as 6 mol dm 3 HC1 solutions.Also tion procedure Artificial seawater and a small amount of a multitracer solution were put in a polyethylene bottle. After the pH value was adjusted to 7.5 with a 1 mol dm`3 Na2CO3 solution, the adsorbent suspension was added to the solution. Its pH value was readjusted to 7.5 when necessary. The suspension was shaken in an 8-shape mode with a shaker at 25° C. After centrifugation, a portion of the supernatant solution was pipetted. The y-ray spectrum of radioactive nuclides in the solutions were measured with a Ge detector. The distribution coefficients (Kd) for each nuclide were calculated as follows: Kd = ( Aads/m )/( Asoln/V) = ((Ai-Af)/Af)(V/m).Aads and Asoln are the radioactivity in the adsorbent and the solution after adsorption equilibrium, respectively. V is volume of the solution (cm'3 ). m is the amount of the adsorbent (g). Ai and AS are the radioactivity in the solution 1106 before and after adsorption equilibrium , respectively. RESULTS AND DISCUSSIONThe distribution coefficients (Kd) of Co . Ga, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Re and Hg at pH 7 .5 and at 25°C are given in TABLE 1. The order of Kd for each element is summarized as follows: hydrated femc oxide > deep-sea sediment > montmorillonite > nearshore sediment kaolinite. The deep-sea sediment used in this study is red clay containing about 1 .5 % iron oxide and 0.5 %

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Factors controlling the chemical composition of marine manganese nodules and crusts: a review and synthesis

Cited by 37 publications

References 76 publications

Characterization of metalliferous sediment from a low-temperature hydrothermal environment on the Eastern Flank of the East Pacific Rise

Characterization of metalliferous sediment from a low-temperature hydrothermal environment on the Eastern Flank of the East Pacific Rise

Assessment of the Mineral Resource Potential of Atlantic Ferromanganese Crusts Based on Their Growth History, Microstructure, and Texture

Study of Removal Mechanisms of Metal Elements From Seawater Using Radioactive Multitracers

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