Deep-sea Fe-Mn Crusts from the Northeast Atlantic Ocean: Composition and Resource Considerations

Muiños, Susana Bolhão; Hein, James R.; Frank, Martin; Monteiro, J. H.; Gáspár, László; Conrad, T. A.; Pereira, Henrique Garcia; Abrantes, Fatima F

doi:10.1080/1064119x.2012.661215

Cited by 60 publications

(43 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The positive values of Ce/Ce*, up to 2.8, may be due to a modest contamination of the serpentinites by hydrogenous Fe-Mn oxyhydroxide crusts and associated fluids, characterized by REE concentrations several orders of magnitude higher than those of the serpentinites, by LREE-enriched patterns; (see Fig. 6 of D'Orazio et al, 2004;Baturin and Dubinchuk, 2011;Muiños et al, 2013) and by a prominent positive Ce anomaly.…”

Section: Major and Trace Elementsmentioning

confidence: 93%

Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N

Boschi

Bonatti

Ligi

et al. 2013

Lithos

View full text Add to dashboard Cite

Section: Major and Trace Elementsmentioning

confidence: 93%

Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N

Boschi

Bonatti

Ligi

et al. 2013

Lithos

View full text Add to dashboard Cite

“…Extremely high concentrations of other metals, for example Te, which are not reported here, could enhance the economics of a project, as could technological advances that would permit lower-cost mining and/or the mining of steep, unstable flank areas, where crustal thicknesses are sometimes higher. The Co concentrations measured in these samples seem to be comparable, or slightly higher than, those elsewhere in the North Atlantic [36] and are therefore considered representative of other Atlantic seamounts. Exceptional crustal thicknesses and/or unusually high concentrations of other economically important metals are likely to be required to make a FeMn crust extraction economically viable under the constraints proposed by Hein et al [16], particularly at lower mining efficiencies.…”

Section: Theoretical Mine-site Evaluationmentioning

confidence: 97%

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

“…Compared with other Fe-Mn oxyhydroxides identified in the EPMA, vernadite shows the highest Cl, S, Ba, Ca, Sr, P and Zn (Table A1, Figure 8). In samples from the DHR Fe-vernadite is dominant, showing several intergrowths with Ni and Ni-Co asbolane and feroxyhyte-ferrihydrite domains and in the analyzed area occurs in association with other Fe-Mn rich phases, quite similar to other crust regions (compare References [79,80]). Asbolane Mn 4+ (O,OH) 2 × (Co,Ni,Mg,Ca)x(OH) 2x × nH 2 O is less dominant but a major concentrator of economically important elements, especially Ni and Co. Asbolane is mainly a product of the transformation of other manganese minerals, often being translated as diagenetic process.…”

Section: Fe-mn Oxyhydroxidesmentioning

confidence: 54%

Mineralogy of Cobalt-Rich Ferromanganese Crusts from the Perth Abyssal Plain (E Indian Ocean)

et al. 2019

View full text Add to dashboard Cite

Mineralogy of phosphatized and zeolitized hydrogenous cobalt-rich ferromanganese crusts from Dirck Hartog Ridge (DHR), the Perth Abyssal Plain (PAP), formed on an altered basaltic substrate, is described. Detail studies of crusts were conducted using optical transmitted light microscopy, X-ray Powder Diffraction (XRD) and Energy Dispersive X-ray Fluorescence (EDXRF), Differential Thermal Analysis (DTA) and Electron Probe Microanalysis (EPMA). The major Fe-Mn mineral phases that form DHR crusts are low-crystalline vernadite, asbolane and a feroxyhyte-ferrihydrite mixture. Accessory minerals are Ca-hydroxyapatite, zeolites (Na-phillipsite, chabazite, heulandite-clinoptilolite), glauconite and several clay minerals (Fe-smectite, nontronite, celadonite) are identified in the basalt-crust border zone. The highest Ni, Cu and Co contents are observed in asbolane and Mn-(Fe) vernadite. There is significant enrichment of Ti in feroxyhyte−ferrihydrite and vernadite. The highest rare earth element (REE) content is measured in the phosphate minerals, less in phyllosilicates and Na-phillipsite. The geochemical composition of minerals in the DHR crusts supports the formation of crusts by initial alteration, phosphatization and zeolitization of the substrate basalts followed by oscillatory Fe-Mn oxyhydroxides precipitation of hydrogenous vernadite (oxic conditions) and diagenous asbolane (suboxic conditions).Minerals 2019, 9, 84 2 of 33 hydrothermal fluids), the two major types of ferromanganese crusts are distinguished: (I) hydrogenetic cobalt-rich ferromanganese crusts; (II) hydrothermal crusts and encrustations (sometimes called stratabound manganese oxides) [15][16][17][18]. Hydrothermal crusts that precipitate directly from low temperature hydrothermal fluids (few tens of degrees up to 200 • C), usually grow significantly faster, even up to 1600-1800 mm/Ma [19]. Ferromanganese crusts in some locations form through a combination of fluid sources and thereby exhibit a mixed origin, primarily either hydrogenetic, diagenetic or hydrothermal-hydrogenetic [15,18,20,21].Co-rich ferromanganese crusts formation is dominated by hydrogenetic processes. The precipitation from bottom waters is extremely slow, with growth rates of 1-5 mm/Ma. The thickest crusts occur in the depth interval between 800-2500 m and show the highest concentrations of critical metals [22]. Some authors limit this depth to the anoxic zone at approximate depths of 1000-1500 m. Below these depths, the thickness of crusts decrease [23][24][25].On the youngest rock outcrops, crusts form mainly patina-thin layers. Most crust surfaces are either botryoidal, smooth or rough, that form under conditions of strong bottom currents. In the thick crusts, 2 to 8 visible or macroscopic layers may be distinguished. The internal layers are usually black and massive, while outer parts are slightly lighter, laminated and more porous [13]. However, crusts with four major layers of oxide layers have been found. The outer-and innermost are massive and show light colors, whereas the...

show abstract

Deep-sea Fe-Mn Crusts from the Northeast Atlantic Ocean: Composition and Resource Considerations

Cited by 60 publications

References 42 publications

Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N

Serpentinization of mantle peridotites along an uplifted lithospheric section, Mid Atlantic Ridge at 11° N

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

Mineralogy of Cobalt-Rich Ferromanganese Crusts from the Perth Abyssal Plain (E Indian Ocean)

Contact Info

Product

Resources

About