Manganese nodules distribution

Manganese minerals are widely distributed oxides, silicates, and carbonates are the most common. The discovery of large quantities of manganese nodules on the floor of the oceans may become a source of manganese. These nodules contain about 24% manganese together with many other elements in lesser abundance. 

Huh C-A, Moore WS, Kadko DC (1989) Oceaitic Th a reconnaissance and implications of global distribution from manganese nodules. Geochim Cosmochim Acta 53 1357-1366 Ingri J (1996) Hydrochemistry of the Kalix River. Lulea University of Technology. Report. 126p (in Swedish)... 

Cronan, D. S. "Deep Sea Nodules Distribution and Geochemistry", p. 11 Mero, J. L. "Economic Aspects of Nodule Mining," p. 327 in Marine Manganese Deposits, Glasby, G. P., ed. Elsevier, Amsterdam, 1977. 

An investigation of the origin and distribution of manganese nodules and the processes by which they selectively concentrate copper, nickel, and other metals was one of llie first major projects under the sea beds Assessment project of the IDOE program. At a workshop attended by over a hundred scientists from various countries, the most likely locations... 

The main components of marine sediments are inorganic aluminosilicate minerals which are usually accumulated on the sea floor by river and other geological activities, and also skeletons and shells of marine organisms (mainly calcium carbonate and silica) [2]. Of course, some metal salts or particulates which precipitate from seawater form new minerals, e.g. manganese nodules [2]. The chemical compositions of the three principal types of sediments in the ocean are shown in Table 12 [105], Most of the sediments found in the deep-sea floor are mixtures of these three principal minerals. Study of the sediments in the oceans and seashores can provide important data related to geochemical, oceanographical or biological circulation and deposition of elements, formation and distribution of marine sediments, and exploitation of marine resources. 

Figs. 10 and 11 show the distributions of manganese nodules and of the sedimentation rates in the world oceans. From the similarity of these two distributions it can be concluded that the main factor regulating the distribution of manganese nodules is the sedimentation rate. 

We have shown that [Ni2+]-OMS-2 and [N 2+]-OMS-1 catalyze the selective conversion of hexane to 1-hexene. Stainless steel flow reactors of 1/4 diameter containing 0.5 g catalyst, charges of 7 g n-hexane in 2 h, 1 atm pressure and temperatures of 500°C are used in these experiments. Both gas chromatography (GC) and mass spectrometry (MS) analyses are done to monitor product distributions. Conversions as high as 60% and selectivities of 90% (to the terminal olefin) have been observed for the OMS-2 system. This may be a consequence of the better shape selectivity of [Ni2+]-OMS-2 (4.6 A tunnel) versus (Ni2+]-OMS-1 (6.9 A). The latter material is not as selective or active. Systems that do not contain N 2+ are totally inactive.91 There is precedence for dehydrogenation activity of these systems since manganese nodules have been reported to be excellent catalysts for dehydrogenation of cyclohexane.63... 

Dean, W.E., Ghosh, S.K., Krishnaswami, S. and Moore, W.S., 1973. Geochemistry and accretion rates of freshwater ferromanganese nodules. In M. Morgenstein (Editor), The Origin and Distribution of Manganese Nodules in the Pacific and Prospects for Exploration. Hawaii Institute of Geophysics, pp. 13—20. 

Mero, J.L., 1965. The Mineral Resources of the Sea. Elsevier, Amsterdam, 312 pp. Morgenstein, M., 1973. The origin and distribution of manganese nodules in the Pacific and prospects for exploration. Symposium, Honolulu Hawaii, 23—25 July, 1973, Valdevia Manganese Exploration Group, Univ. Hawaii, and IDOE-NSF. 175 pp. 

Mullineaux, L.S. (1987) Organisms living on manganese nodules and crusts distribution and abundance at three North Pacific sites. Deep-Sea Research, 34, 165-184. 

Calvert, S. E., and Price, N. B. (1977). Shallow water, continental margin and lacustrine nodules Distribution and geochemistry. In Marine Manganese Deposits (G. P. Glasby, ed.), pp. 45-86. Elsevier, Amsterdam. 

In the following section, the distribution, mineralogy and composition of manganese nodules from three of these regions is considered in order to illustrate the different modes of formation of nodules in different settings. A detailed comparison of the characteristics of the nodnles from these three regions has already been presented by Glasby et al. (1983). 

Fig. 11.8 Schematic map showing the distribution of manganese nodules in the Pacific Ocean compiled as part of the Circum-Pacific Map Project (Piper et al. 1985). The contours represent the percentage cover of the ocean floor by manganese nodules. Diagram prepared with the permission of D.Z. Piper, USGS.

Cronan, D.S., 1987. Controls on the nature and distribution of manganese nodules in die western equatorial Pacific Ocean. In Teleki, P.G., Dobson, M.R., Moore, J.R. and von Stackelberg, U. (eds). Marine minerals Advances in research and resource assessment. D. Reidel, Dordrecht, pp. 177-188. 

Glasby, G.P., Friedrich, G Thijssen, T. Pluger, W.L., Kunzendorf, H., Ghosh, A.K. and Roonwal, G.S., 1982 Distribution, morphology, and geochemistry of manganese nodules from the Valdivia 13/2 area, equatorial North Pacific. Pacific Science, 36 241-263. 

Glasby, G.P., Gwozdz, R., Kunzendorf, H., Friedrich, G. and Thijssen, T, 1987. The distribution of rare earth and minor elements in manganese nodules and sediments from the equatorial and S.W. Pacific. Lithos, 20 97-113. 

Jeong, K.S., Kang, J.K., Lee, K.Y. Jung, H.S., Chi, S.B. andAhn, S.J., 1996. Formation and distribution of manganese nodule deposits in the western margin of Clarion-Clipperton fracture zones, northeast equatorial Pacific. Geo-Marine Letters, 16 123-131. 

Margolis SV and Burns RG (1976) Pacific deep-sea manganese nodules their distribution, composition, and origin. Annual Review of Earth and Planetary Science 4 229-263. 

General distribution of Fe-Mn nodules in the Pacific and Atlantic oceans. Source-. From Kennett, J. (1982). Marine Geology, Prentice Flail, Inc., p. 500. After Cronan, D. S. (1977). Marine Manganese Deposits, Elsevier Science Publishers, pp. 11-44. 

Manganese is relatively abundant, constituting about 0.085% of the earth s crust. Among the heavy metals, only Fe is more abundant. Although widely distributed, it occurs in a number of substantial deposits, mainly oxides, hydrous oxides, or carbonate. It also occurs in nodules on the Pacific seabed together with Ni, Cu, and Co. 

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