Ferromanganese Nodules Research Articles

Forms and distribution of Ce in a ferromanganese nodule

Author(s): Marcus, MA; Toner, BM; Takahashi, Y | Abstract: We studied the distribution and speciation of Ce in a previously-characterized ferromanganese nodule from the South Pacific Gyre using X-ray microspectroscopy.We find Ce in three types of environment – diffusely in all parts of the nodule except the Fe-rich, Mn-poor “matrix”, fluorapatite grains with a negative Ce anomaly suggestive of an authigenic origin, and localized spots whose composition is consistent with a pseudobinary mixture of sorbed Ce4+ and a mix of sorbed Ce3+ and CeO2. In contrast with some other elements such as Ti, there is no clear correlation of the Ce concentration in the diffuse areas with either that of Mn, Fe or any linear combination of the two.We argue that the CeO2 came from oxidation of Ce3+ in the water column, while the Ce in the Mn-rich regions may have been initially deposited as Ce4+ and then partially reduced.

Ferromanganese nodules of freshwater reservoirs of Ol’khon Island (Baikal) and the Kulunda Plain (West Siberia)

Morphology and mineralogical and geochemical compositions of freshwater ferromanganese nodules of Ol’khon Island (Sasa Formation) and Kulunda Plain (Lake Porozhnee) were studied. The study has shown rhythmic structures of the nodules, formed by macro- and microlayers with mineralized microflora. The layers are composed of either crystalline Mn mineral phases and finely dispersed Fe phases (Lake Porozhnee) or, on the contrary, crystalline goethite and X-ray amorphous Mn phases (Ol’khon Island). Separation of Mn and Fe mineral phases in the nodules proceeded during their formation and diagenesis. The freshwater nodules show both high (Lake Porozhnee) and low (Ol’khon Island) Mn/Fe ratios. The predominance of Fe phase in the Ol’khon nodules accounts for their high contents of REE, including Ce. The Porozhnee nodules grew, most likely, more rapidly, which is reflected in their low REE contents and Ce anomaly. The examined chemical and mineral compositions, textures, and structures of the nodules testify to the low-temperature hydrothermal source of their ore substance.

Determination of lead isotope ratios in Mn–Fe-rich nodules by laser ablation multi-collector inductively coupled plasma mass spectrometry

In this study, Pb isotope ratios in ferromanganese nodules were determined with good repeatability and minimum laboratory bias using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS).

Distribution of n-alkanes in the ferromanganese nodule–sediment–pore water system (Clarion–Clipperton Fracture Zone)

The paper presents the first results of a comparative study of the composition and distribution of organic matter (OM) (Corg, n-alkanes, Pr, Phy) in samples of the ferromanganese nodule–sediment–pore water system taken at a single site in the Clarion–Clipperton Fracture Zone, Pacific Ocean. Samples were taken during Cruise 120 of R/V James Cook in 2015. The results of the comparison of organogeochemical parameters in the lipid fraction of OM in ferromanganese nodules of different size and morphology with the underlying sediment (0–1 cm) and pore water revealed both principle genetic affinity of OM therein and significant discrepancies between the processes of diagenesis during the formation and growth of each individual ore sample.

Processing of Ferromanganese Nodules of the Pacific Ocean

Manganese-containing ores in Russia and prospects for expanding the resources by including ferromanganese nodules (FMN) are analyzed. Processes for manganese-containing materials are reviewed. The combined pyro-hydrometallurgical processing of deep-water ferromanganese nodules from the Clarion–Clipperton Zone in the Pacific Ocean is described. The results of studies on the sulfating roasting of FMNs with pyrite and the results of the one-stage neutral leaching of cinders are presented. It is concluded that it is promising to combine the processing of nodules and preliminary roasting to produce saleable concentrates of manganese and non-ferrous metals.

Ferromanganese nodules from the East Siberian Sea near Bennett Island

Ferromanganese nodules recovered from the bottom of the East Siberian Sea near Bennett Island are studied by coupled ultramicroscopic and ICP-MS methods. The majority of nodules are flattened dense formations 2.5 to 10 cm in cross section and circled by a thick rim, which is common in nodules from other Arctic basins. The major components of nodules are iron and manganese oxides in the form of ferruginous vernadite and magnetite, as well as accessory minerals, including apatite and titanomagnetite. The major and trace element compositions of nodules are comparable to Arctic nodules from other Arctic seas, but somewhat different compared to those from the Mendeleev Rise. A specific feature of these nodules is that they contain high amounts of mercury in all samples and a positive europium anomaly in one sample, along with gold; this may be related to the influence of endogenous gas-and-vapor exhalations.

Effect of hydrochloric acid on grain size analysis of the Quaternary red clay rich in tiny ferromanganese nodules, Jiangxi province, southern China

There are many tiny ferromanganese nodules that cannot be found and eliminated easily in Quaternary red clay in southern China. The existence of these tiny ferromanganese nodules may influence grain size analysis results. Therefore, this paper focuses on the effects of the ferromanganese nodules on the grain size analysis and the effects of hydrochloric acid (HCl) on removing these nodules. The experimental results showed that the nodules clearly influenced the results of grain size analysis. The tiny ferromanganese nodules increased the coarse fraction and show a low peak in the coarse fraction of >100 μm on the frequency curves. The addition of HCl in the pretreatment process of grain size analysis can eliminate the effects of these tiny nodules effectively. Additionally, the HCl reacts with clay minerals and causes a reduction of the <4 μm fraction.

Potential Influence of Ocean Acidification on Deep-Sea Fe–Mn Nodules: Results from Leaching Experiments

With the continuous rise in CO2 emissions, the pH of seawater may decrease extensively in the coming centuries. Deep-sea environments are more vulnerable to decreasing pH since sediments in deep oceans below the carbonate compensation depth (CCD) are often completely devoid of carbonate particles. In order to assess the potential risk of heavy metal release from deep-sea deposits, the mobility of elements from ferromanganese (Fe–Mn) nodules and pelagic clays was examined by means of leaching experiments using phosphate buffer solutions ranging in pH from 7.1 to 8.6 (NBS scale). With decreasing pH, the results showed an enhanced leaching of elements such as Li, B, Mg, Si, Sc, Sr, Ba, Tl, and U, but a reduced leaching of V, Cu, Mo, Cd, and W. Elements in leachates originate mainly from exchangeable fractions, and tend to be affected by sorption–desorption processes. Concentrations of most elements did not exceed widely used international water quality criteria, indicating that changes in pH caused by future ocean acidification may not increase the risk of heavy metal release during deep-sea nodule mining operations.

Biogenic mineralization in the ferromanganese nodules and crusts from the South China Sea

Global marine ferromanganese (Fe-Mn) nodules and crusts host immense metal resources, and the metal enrichment mechanism is still in dispute. The South China Sea (SCS) is one of the largest marginal seas in the western Pacific, and its northern slope is a passive continental margin with high sedimentary rate. A large amount of ferromanganese nodules and crusts have been discovered in the SCS northern slope. Previous investigations shown that the SCS nodules/crusts are often smaller and thinner, and contain higher Si and Al but lower Mn, Co and Ni than the Western Pacific nodules and crusts. In this study, high resolution scanning electron microscope (HR-SEM) and energy dispersive spectrometer (EDS) were performed to explore the microorganism activities with respect to the nodules/crusts formation. Various biogenic signature and microfossils in the SCS Fe-Mn nodules/crusts are recorded. These bio-marks and microfossils present several morphological types: tubiform burrows, bulbiform organism fossils, mould structures, cylindrical protozoan, globular growth structures, isolated spheroidal bacteria and biofilms. These mineralized bio-marks and microfossils are mostly protozoans belonging to various bacteria, biofilm, diatoms and coccoliths with Mn and/or Fe on their surface. Using the electron probe micro analyzer (EPMA), the microfossil-rich areas contain higher Mn than the surrounding microfossil-poor areas are observed. The abundance of bio-marks and microfossils and their geochemical features support a dominant role of microorganism activities in the SCS nodule/crustal formation. We proposed that microorganisms may have served as seeds/templates to induce mineral deposition in the nodules and crusts, and chemical oxidation and other abiotic mechanisms also contribute to the Fe-Mn oxide formation. The biogenic hypothesis provides another perspective to further understand the formation of deep marine Fe-Mn nodules/crusts, and will be important for exploration of Fe and Mn metals in the future.

Study on Nanophase Minerals and Their Associated Trace Elements in Freshwater Ferromanganese Nodules From Green Bay, Lake Michigan

Study on Nanophase Minerals and Their Associated Trace Elements in Freshwater Ferromanganese Nodules From Green Bay, Lake Michigan

Ligand exchange adsorption and coordination structure of Pd on δ-MnO2 in NaCl solution

Palladium is highly accumulated in ferromanganese (Fe-Mn) nodules and crusts relative to its concentration in seawater but the mechanism by which Pd(II) is incorporated remains poorly understood, probably because the Pd concentration in Fe-Mn nodules and crusts is fairly low. In this study, we investigated the local coordination structure of Pd(II) adsorbed on δ-MnO2, using X-ray absorption fine structure spectroscopy to clarify the mechanism by which Pd is incorporated into Fe-Mn nodules and crusts. Adsorption experiments of Pd(II) on δ-MnO2 were conducted in 0.1 and 0.5M NaCl solutions, in which the negatively charged chloride complexes PdCl42−, PdCl3−, and PdCl3OH2− were predominant species. The distribution coefficient of Pd between δ-MnO2 and solution, Kd(Pd)=[Pd]solid/[Pd]solution (L/kg), increased from ~2×103 to ~4×106 with increasing pH. X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses indicated that Pd was adsorbed on δ-MnO2 through ligand exchange, from Cl coordination to O coordination. Furthermore, curve fitting of EXAFS spectra demonstrated the formation of two different inner-sphere complexes, bidentate-mononuclear and bidentate-binuclear complexes, and this finding was supported by density functional theory calculations. The formation of inner-sphere complexes is reasonable given the relatively large Kd(Pd) values obtained from adsorption experiments and the large apparent Kd(Pd) values calculated from reported data on Fe-Mn nodules and crusts and seawater.

南鳥島EEZ南東部全域に分布するマンガンノジュール ～YK16-01航海速報～

南鳥島EEZ南東部全域に分布するマンガンノジュール ～YK16-01航海速報～

Trace elements in ferromanganese nodules from the central indian ocean basin

ABSTRACTThirty-three bulk ferromanganese nodules from the sediment–water interface of siliceous sediment domain from the Central Indian Ocean Basin were analyzed for 50 elements including 6 new (Be, As, Se, Sn, Sb, and Bi) using inductively coupled plasma–mass spectrometer. The Mn/Fe ratio and triangular plot (Fe-Mn-{Cu+Ni+Co × 10}) suggest that ferromanganese nodules are of hydrogenetic, early diagenetic, and diagenetic origin. In the ferromanganese nodules, Mo, Sb, Bi, and As are highly enriched ∼320, 160, 90, and 50 times compared with upper continental crust, respectively. A majority of the elements such as Be, Sc, Ti, V, Co, As, Se, Sr, Y, Zr, Nb, Sn, rare earth elements (REEs), Pb, Bi, P, Th, U, Hf, and Ta are associated with Fe, whereas, Cu, Ni, Zn, Mo, Li, Ga, Sb, Mg, and Cs are associated with Mn in the ferromanganese nodules. Redox proxies such as U/Th (0.14) and Mo/Mn (0.0019) ratio in the ferromanganese nodules suggest their formation under oxic conditions.

Cosmic dust in modern ferromanganese nodules

This work is about the identification of modern cosmic dust that had survived heating during its high-velocity passage through the Earth’s atmosphere from 3He isotope concentrations in marine (Gulf of Finland) ferromanganese nodules (FMNs). The measured bulk composition of helium includes components of various origins, enabling the determination of the age (1800 years) of the shallow-water Baltic FMNs and the average time of exposure (8 × 107 years) of cosmic dust particles during their existence in space. The concentration of cosmic dust per gram of FMN material is found to be 0.036 μg. The contribution of solar-wind helium to the Earth’s atmospheric helium is found to be small. The experiments are conducted by the stepheating method in vacuo with the subsequent mass-spectrometric analysis of the helium released from the samples.

Composition and genesis of ferromanganese deposits from the northern South China Sea

Marine ferromanganese (Fe-Mn) nodules and crusts are archives of past environmental conditions and potential mineral resources. Over the last 30years, many have been discovered in the northern South China Sea (SCS). To determine the origin of the Fe-Mn deposits, a comprehensive laboratory analysis of physical properties, mineralogy and geochemistry was conducted on newly collected Fe-Mn nodule/crust samples. The results revealed that there are three types of Fe-Mn deposits: (1) Fe-rich nodules containing essentially goethite occur on the northeastern slope of the SCS, with high Fe, low Mn (Mn/Fe=0.03) and low trace metals and rare earth elements concentrations; (2) Smooth Fe-Mn nodules and crusts composed of asbolane, todorokite and CFA occur along the northwestern marginal of the SCS that have similar Fe and Mn contents (Mn/Fe=1.21), moderate trace metal enrichments, and a positive Ce anomaly; (3) Fe-Mn nodules and crusts composed of asbolane, todorokite and birnessite that occur in the central basin of the SCS have higher Mn and lower Fe contents (Mn/Fe=1.45). This depositional pattern was associated with major changes in oceanographic conditions and tectonic regimes. The northeastern slope deposits occur in a contourite depositional system, are strongly enriched in Fe relative to Mn (average 38.7% and 0.96%, respectively), formed from the combination of hydrogenetic and diagenetic processes. We propose a new genetic model for Fe-Mn nodules, which formed through the oxidation of pyrite and pyrite-barite concretions that formed by rapid early diagenetic growth (average 3320mm/Myr) on continental margins above the carbonate compensation depth, and dominated by hydrocarbon seep structures and strong erosive action of bottom currents along the northeastern slope. In contrast, the introduction of vigorous deep-water flow from the North Pacific promoted the slow growth (4–7mm/Myr) of hydrogenetic Fe-Mn nodules and crusts along the northwestern margin. Finally, hydrogenetic growth of Fe-Mn nodules and crusts in the central basin may have been enhanced by volcanic processes. Our data provide new insights into the genesis and province characteristics of the Fe-Mn nodules and crusts of the northern SCS.

Determination of the platinum-group elements and gold in ferromanganese nodule reference material NOD-A-1

The concentrations of Ru, Pd, Ir, Pt, and Au were determined in a ferromanganese nodule reference sample NOD-A-1 by inductively coupled plasma mass-spectrometry. Sample preparation procedures include acid digestion and anion exchange preconcentration. Standard addition method was used to eliminate losses of the analyte during the chromatographic separation. The results are in agreement with previously published data. The low level of intermediate precision for Au between different subsamples of the same sample probably originates from the heterogeneous distribution of Au in ferromanganese nodules. The accumulation of PGE in ferromanganese nodules was studied using international reference samples.

Ferromanganese nodules from the Kara Sea: Interrelation between organic matter and ore elements

This study presents data on Fe–Mn nodules first recovered from the northeastern part of the Kara Sea. Analysis of the geochemical indicators of organic matter and major and trace element compositions of nodules showed that samples with strong Mn enrichment (Mn/Fe = 2.38, on average) are dominated by terrestrial organic matter (OM), whereas Fe-rich samples (Mn/Fe = 0.20, on average) are dominated by marine biogenic OM. The variation in the n-alkane abundances in the studied nodules is independent of the sampling sites and nodule morphology. This study was conducted for the first time in the Artic region.

WORLD OCEAN - LAST RESERVE OF HUMANITY

Analysis of mineral resources base located in offshore zone and ocean space is an important aspect of development of industrial and economic potential. The issues of control over the Earth’s mineral resources as one of the most important components of geopolitical leadership are considered. It is shown that mineral resources of shelf zone, continental slope, and ocean floor are of the greatest interest from the viewpoint of possible commercial development. Data on the major oil and natural gas fields, deep-sea deposits of polymetallic sulfides, ferromanganese nodules, and cobalt-manganese crusts are analyzed. The mechanisms of state management in the field of using the resources of World Ocean and developing marine mining industry in Russia are substantiated.

Ecological and Economic Prerequisites for the Extraction of Solid Minerals from the Bottom of the Arctic Seas

The world ocean has huge reserves of minerals that are contained directly in the water, as well as on the surface of its bottom and in its subsoils. The deposits of solid minerals on the surface of the bottom of the World Ocean are considered the most promising for industrial extraction. The deposits of ferromanganese nodules, cobalt-manganese crusts and polymetallic sulphides are considered as an object of extracting more often than others. There are the largest deposits of ferromanganese nodules in the central and southern parts of the Pacific Ocean, in the central part of the Indian Ocean, and in the seas of the Arctic Ocean near Russia. The deposits of ferromanganese nodules are a serious alternative to deposits of manganese ore on land. However, there are many factors influencing the efficiency of the development of ferromanganese deposits, the most significant are: the content of the useful component in the ore, the depth of the bottom and the distance from the seaports. It is also necessary to take into account the possible environmental consequences of underwater mining.

Geology and geochemistry of ferromanganese nodules in the Japanese Exclusive Economic Zone around Minamitorishima Island

Geology and geochemistry of ferromanganese nodules in the Japanese Exclusive Economic Zone around Minamitorishima Island