ALBERT

Description: Concentrically ringed manganese nodules, similar in form to many found on modern ocean and sea floors, occur in a very fine grained argillaceous sandstone bed of the Permian Park City Formation near Dillon, Montana. They are enriched in many rare elements and contain us much as 2.5 percent zinc, l.3 percent nickel, and 0.22 percent cobalt. The manganese minerals are chalcophanite and todorokite. The nodules probably formed in a shallow marine oxidizing environment on the western side of the Permian sedimentary basin. The occurrence of an appreciable amount of fluorite in the bed suggests that the water was saline.

Description: Ferromanganese nodules in the deep-sea and in freshwater lakes usually accrete layers rich in manganese oxides alternating with layers rich in iron oxides. The mechanism producing these alternating layers is unknown; indeed, the mechanism producing the nodules themselves is unknown. In Oneida Lake, New York, precipitants from the lake water and the surfaces of nodules at the sediment-water interface are enriched in Mn, whereas nodules buried in lake sediments have surface layers enriched in Fe. It is hypothesized here, using field and laboratory evidence, that reduction and mobilization of Mn from the nodule surface during periods of anoxic sediment cover produce the high Fe layers observed in the nodules.

Description: In the 1960s and 1970s, the Kennecott Corporation conducted a number of activities in the evaluation of manganese nodule deposits as well as in their possible hydrometallurgy.

Description: Deep sea manganese nodules from the Central Pacific Basin are mainly composed of 10Å manganite and d-MnO2 Two zones equivalent to the minerals are evidently distinguishable according to their optical properties. Microscopic and microprobe analyses revealed quite different chemical compositions and textnral characteristics of the two zones. These different feature of the two zones of nodules suggest the different conditions under which they were formed. Concentrations of 11 metal elements in the zones and inter-element relationships show that the 10Å manganite zone is a monomineralic oxide phase containing a large amount of manganese and minor amounts of useful metals, and that the d-MnO2 zone which is apparently homogeneous under the microscope is a mixture of three or more different minerals. The chemical characteristics of the two zones can explain the variation of bulk composition of deep sea manganese nodules and inter-element relationships previously reported, suggesting that the bulk compositions are attributable to the mixing of the 10Å manganite and d-MnO2 zones in various ratios. Characteristic morphology and surface structure of some types of nodules and their relationships to chemistry are also attribut able to the textural and chemical features of the above mentioned two phases. Synthesis of hydrated manganese oxides was carried out in terms of the formation of manganese minerals in the ocean. The primary product which is an equivalent to d-MnO2 was precipitated from Mn 2+ -bearing alkaline solution under oxigenated condition by air bubbling at one atmospheric pressure and room temperature. The primary product was converted to a l0Å manganite equivalent by contact with Ni 2+, Cu 2++ or CO2+ chloride solutions. This reaction caused the decrease of Ni2+, Cu2+ or CO2+ concentrations and the increase of Na+ concentration in the solution. The reaction also proceeded even in diluted solutions of nickel chloride and resulted in a complete removal of Ni2+ from the solution. Reaction products were exclusively 10Å manganite equivalents and their chemical compositions were very similar to those of 10Å manganite in manganese nodules. The maximum value of(Cu+Ni+Co)/Mn ratio of 10Å manganite zones in manganese nodules is 0.16, and the Ni/Mn ratio of synthetic 10Å manganite ranges from 0.15 to 0.18 with the average of 0.167.

Description: The major and some of the minor constituents and the rate of accumulation of manganese nodules in the western North Pacific were determined. Manganese concentration in the nodules ranged from 20 to 30 per cent in the acid soluble fraction. As to the rare earth concentration, enrichment of cerium was observed in the manganese nodule as compared with that in shales or sea water. Thorium to uranium ratio in the nodule ranged from 9.4 to 14.3, which was very much higher than that in sea water. From the distribution of excess ionium, excess protactinium and Io/Th ratio, a rate of accumulation of 7 mm per million years was obtained with the surface layer of several mm in thickness of the JEDS-4-E4 nodule.

Description: The main objective of the project was to develop a geochemical method for exploration of ores associated with granitic rocks. Fe and Mn oxidates were sampled in streambeds and lakes from 129 localities in Southeastern Norway. 65 of these localities are situated in the northern Oslo Graben. The samples were examined mineralogically and chemically by a variety of methods. Geochemical maps of the element content in oxidates show regional distribution patterns for several elements. Sampling and analysis of oxidates can be used in exploration for mineralizations such as the Skrukkelia Mo-deposit in the northern Oslo Graben. New anomalies (especially for Zn and W) have been detected. Appendix I contains a description of samples, chemical and mineralogical determinations performed on the samples, backscattered electron image-, X-ray image- and scanning electron image pictures of the oxidate preparates. Appendix II contains spectral plots, point analysis with the microprobe, X-ray diffractograms, analytical results, correlation coefficient matrix, scatterplots, frequency distributions and information on data storage. Appendix III containS maps of the element content in oxidates.

Description: Manganese oxide crusts similar to those reported from the Mid-Atlantic Ridge rift valley by Scott et al., 1974 (https://doi.pangaea.de/10.1594/PANGAEA.848726) were dredged at two sites near the Galapagos spreading axis on ocean floor estimated from magnetic anomalies to be 2.4 and 0.3 m.y. old. Compared to the typical ocean-floor manganese deposits attributed to precipitation from seawater, the 2-6 cm thick manganese crusts reported here exhibit very low Fe/Mn and low 232Th/238U ratios, as well as lower transition metal and higher manganese concentrations. The manganese crusts were deposited several orders of magnitude faster than the more common hydrogenous nodules; this fact together with other geochemical characteristics and the geophysical environment suggests the manganese deposits reported here are of hydrothermal origin.

Description: Manganese nodules have been analysed at the Scripps Institution of Oceanography after having been ground to to a diameter less than 74 microns. Some analysises were performed on pellets by X-ray Emission Spectroscopy for 1000 Seconds. All concentrations have been corrected to 110 degrees Celsius drying conditions (see: https://doi.pangaea.de/10.1594/PANGAEA.854202).

Description: The major and minor element compositions of a suite of abyssal sea-floor ferromanganese nodules and associated sediments from the eastern central Pacific have been used to examine inter-element relationships and the mineralogy of the nodules, the relationship between the composition of nodules, and their associated sediments and regional variations in composition with respect to likely modes for formation of such deposits. Apart from Mn and Fe, significant proportions of the total Ti, Ca, Mg, K, Ba, Sr, Th and Y and almost all the P, As, Ce, Co, Cu, Mo, Ni, Pb, Zn and Zr are present in the oxide fractions of the nodules. The Mg, Ba, Cu, Mo, Ni and Zn contents are significantly correlated with the total Fe content. Nodules from the northeastern tropical Pacific have Mn/Fe ratios highter than those in the oxide fractions of their associated sediments, todorokite as the principal Mn phase and relatively high concns of minor elements associated with Mn. Nodules from the south central Pacific have Mn/Fe ratios similar to those in the oxide fractions of the associated sediments, {delta}-MnO Sub(2) as the only Mn-phase, and relatively high concns of minor elements associated with Fe. There appears to be a smooth gradation in composition in the tropical Pacific between these 2 end members. The retional compositional variation is interpreted as a reflection of different sources of metals for, and different growth mechanisms of, sea-floor nodules. The oxide precipitate from sea water consists of {delta}-MnO Sub(2), has a relatively low Mn/Fe ratio and minor element contents related to the total Fe and Mn({delta}-MnO Sub(2)) content. The oxide precipitate forming in areas of very low sedimentation as a result of diagenetic remobilisation in the surface sediment consists of todorokite, and has a high Mn/Fe ratio and enhanced metal content in the Mn-(todorokite) phase. Available information on the morphology and compositional variation of individual nodules from the tropical Pacific corroborates these contrasting metal sources and suggests that they can be resolved on the scale of an individual oxide concretion.

Description: Bulk composition of ferromanganese nodules from the pelagic environment of the Pacific Ocean is apparently related to nodule-growth rate, sediment-accumulation rate, and biologic productivity in the overlying seawater. Nodules with a high Mn/Fe ratio and high Ni and Cu concns tend to occur in areas where primary productivity in the surface layer of the ocean is high and the sediment accumulation rate low. They may have a Mn/Fe ratio as low as one and accrete at rates as low as 1 mm/10 M yrs. Nodules with a larger Mn/Fe ratio apparently have growth rates that are greater by as much as a factor of 10.