Micronodules

In a detailed study of micronodules from various areas of the Pacific, Stoffers et al. (1984) showed that micronodules are characterized by regional variations in shape, texture, mineralogy and composition. Micronodules from the Southwestern Pacific Basin are most abundant in the dark brown clays of the central part of the basin. Mineralogically, these micronodules consist of 10 A manganate and 5Mn02 with traces of quartz, phillipsite, quartz and feldspar. They have Mn/Fe ratios of 2.4 and Ni+Cu contents of 1.3%. These Mn/ Fe ratios are somewhat higher than for the associated nodules but the Ni+Cu contents somewhat lower. The micronodules are botiyoidal with smooth surface texture. Under the SEM, the surfaces of the micronodules display a honeycomb texture. 

It is seen that, although Mn/Fe ratios in micronodules 20 can occur, particularly in the Peru Basin, there is no well-defined point of reversal such as observed for Mn nodules (Fig. 11.14), although there is a flattening of the curve at a Mn/Fe ratio of about 

This is a consequence of the fact that the micronodules occur within the sediment column where 

Three principal Mn oxide minerals are found in Mn nodules and crusts. Their principal X-ray diffraction peaks are given below together with their alternative mineral names (in parenthesis)  

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Stein LY, La Dnc MT, Grnndl TJ, Nealson KH. 2001. Bacterial and archaeal popnlations associated with freshwater ferromanganous micronodules and sediments. Environmental Microbiology 3 10-18. 

We have also observed the partial dissolution of micronodules within the sediment. The elements which are first dissolved from micronodules are primarily the... 

Fig. 14. Different particles occurring in radiolarian ooze Black micronodules, patchy clay aggregates, glassy sharp dged fragment volcanic ash. (Clay aggregates can partly be formed as weathering products of volcanic ash or partly be new built).

Fig. 15. I junded manganese micronodules separated magnetically from radiolarian ooze. They usually r ergrow radiolarians or clay mineral aggregates.

Fig. 16. Elongated shape of manganese micronodules (due to filling of small worm holes or overgrowing sponge needles).

The mobilized metals are reprecipitated in the nearly liquid layer on the sediment water interface. They repr ipitate partly on the surface of manganese nodules located there. The other pirt precipitates within the sediment, forming again micronodules or disseminated precipitates. A portion of the metals again diffuses into bottom-near sea-water. 

Stoffer P., Glasby G. P., and Frenzel G. (1984) Comparison of the characteristics of manganese micronodules from the equatorial and southwest Pacific. Tschermaks Mineral Petrogr. Mitt. 33, 1-23. 

The Ni concentration of crustal rocks (58 53 p,g g ) is substantially greater than the average world soils (23 3 p,g g ), but essentially equal to continental sedimentary materials (49 13 p,gg ). Riverine particulate matter (90p,gg ) is nearly twice the Ni concentration of these continental sedimentary materials and deep-sea clay is nearly three times (230 p-g g ) that concentration. As noted for Cu, the substantial Ni enrichment of deep-sea clays is due to the presence of ferromanganese micronodules in the oxidized surficial sediment column (Drever, 1988). 

A dental laboratory technician developed progressive exertional dyspnea and cough associated with pulmonary granulomatosis. Lung function studies showed a restrictive pattern with a low diffusion capacity. A high-resolution CT scan showed micronodules in both... 

Fig. 11.19 A plot of Ni+Cu against Mn/Fe for micronodules from various areas in the Pacific (after Stoffers et al. 1984). SO-06 samples taken from the Clarion-Clipperton F.Z. region, SO-11 from the Peru Basin and SO-14 from the Southwestern Pacific Basin.

Dekov, V.M., Marchig, V., Rajita, I. and Uzonyi, I., 2003. Fe-Mn micronodules born in the metalliferous sediments of two spreading centres the East Pacific Rise and Mid-Atlantic Ridge. Marine Geology, 199 101-121. 

Kunzendorf, H., Glasby, G.P., Stoffers, P. and Pluger, W.L., 1993. The distribution of rare earth and minor elements in manganese nodules, micronodules and sediments along an east-west transect in the southern Pacific. Lithos, 30 45-... 

Stoffers, R, Glasby, G.P., Thijssen, T., Shrivastava, PC. and Melguen, M., 1981. The geochemistry of co - existing manganese nodules, micronodules, sediments and pore waters from five areas in the equatorial and South - West Pacific. Chemie der Erde, 40 273-297. 

Rossberg A, Baraniak L, Reich T, Hennig C, Bernhard G, Nitsche H (2000) EXAFS structural analysis of aqueous uranium(VI) complexes with lignin degradation products. Radiochim Acta 88 593-597 Rothe J, Kneedler EM, Pecher K, Tonner BP, Nealson KH, Grundi T, Meyer-Ilse W, Warwick T (1999) Spectromicroscopy of Mn distributions in micronodules produced by biomineralization. J Synchrotron Rad 6 359-361... 

Nickel and zinc in soil ferromanganese nodules. One of the most efficient and durable process responsible for trace metal sequestration in soils is the formation of ferromanganese micronodules, which often have been compared to the well-known oceanic Mn nodules (Glasby et al. 1979 White and Dixon 1996 Han et al. 2001) (Fig. 30a). Although soil micronodules are the premier reservoir for many trace elements in soils, the crystal chemistry of the sequestered elements remains unknown. Chemical analyses of individual nodules from Sicilia and New Zealand showed that some elements, such as Co, Ce, Ba, Pb, Ni, are several times to more than one order of magnitude enriched in the concretions relative to the soil matrix, whereas others are less (e g., Zn) or even depleted (Childs 1975 Palumbo et al. 2001) (Fig. 30b). Since nodules are formed in situ within the soil matrix by local enrichment of Fe and Mn oxides, the observed difference of metal enrichment in the concretions relative to the soil matrix likely results from a difference of metal affinity for soil minerals. The micronodule analyzed here by... 

Manganese nodules, together with micronodules and encrustations, are ferromanganese oxide deposits which contain variable amounts of other elements... 

Large patches of belite belite nests from coarse quartz Selective reaction of raw mix components clay at lower temperature than that for quartz, muscovite, hornblende, and Ca-feldspars resulting in early nodulation (micronodules) and clinker dust with high lime saturation factor (Fundal, 1980)... 

In 460 autopsied coal miners from West Virginia on pathologic examination 96 % had macules, 70 % micronodules, 45% macronodules, 15% silicosis, and 28% progressive massive fibrosis (Vallya-THAN et al. 1996). 

In Cushing s disease, the P-450np immunoreac-tivity was intensive in cortical micronodules and inner zona fasciculata and zona reticularis, and relatively intensive in the zona glomerulosa and outer zona fasciculata in idiopathic hyperaldosteronism, corresponding to the sites of active steroidogenesis (Sasano et al. 1988). 

Fig. 26.21. A 37-year-old man with pulmonary alveolar microlithiasis. Axial CT image shows miliary distributed calcified micronodules predominantly located in the middle and lower zones of both lungs. Also note the formation of small subpleural cysts and subpleural emphysema and the formation of the pathognomonic black subpleural line (white arrows)...

Mycoplasma pneumoniae Outpatient Angiotrophic micronodules, tree-in-bud... 

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