 | Nahon, Daniel, Beauvais, Anicet, Boeglin, Jean-Loup, Ducloux, Jacques, Nziengui-Mapangou, Pacome (1983) Manganite formation in the first stage of the lateritic manganese ores in Africa. Chemical Geology, 40 (1) 25-42 doi:10.1016/0009-2541(83)90089-x | Journal (article/letter/editorial) | | V., Amsterdam 25 Printed in The Netherlands MANGANITE FORMATION IN THE FIRST STAGE OF THE LATERITIC...3COMILOG, Service Prospections Extdrieures, Moanda (Gabon) (Received June 23, 1982; revised and accepted...Ducloux, J. and Nziengui-Mapangou, P., 1983. Manganite formation in the first stage of the lateritic...central West Africa permit the observation of manganite formation on rocks of different primary nature...carbonate sequence (Moanda, Gabon) manganite replaces thodochrosite. In both areas manganite occurrence is |  | Parc, Sylvie, Nahon, Daniel, Tardy, Yves, Vieillard, Philippe (1989) Estimated solubility products and fields of stability for cryptomelane, nsutite, birnessite, and lithiophorite based on natural lateritic weathering sequences. American Mineralogist, 74 (3-4) 466-475 | Journal (article/letter/editorial) | | hydroxides. Among these major manganeseoxy-hydroxides, manganite (Mn3+ooHiuno pvrolusite (Mn4+or) are well crystallized...on manganiferoussedimentary rocks in the Moanda area (Gabon), and in the Azul area (northern Brazil)...Ca-freegarnet.At the extremebase ofthe profile, only manganite(Mn3+OOH) developsfrom tephroite and manganoancalcite...process.Nsutite replaces either earlier-formed manganite or birnessite, which occursin the middle of the...The second profile occurs at the Moanda weathering ore-body, in Gabon. The Precambrian sedimentary parent |  | | Journal (article/letter/editorial) | | ACCOMPANYING PHASES IN A LATERITIC PROFILE OF MOANDA, GABON M. AMOURIC,I S. PARC,2 AND D. NAHON2 I...France Abstract- Unheated natural mixtures of manganite and secondary pyrolusite, from the same lateritic...structure and in particular (210) microfissures in manganite were noted as signs of structural accommodation...adjacent to manganite. This is the first report ofa natural occurrence of'r-Mn203' The manganite-pyrolusite...transmission electron microscopy, Laterite, Manganese, Manganite, Pyrolusite, Topotactic transformation. INTRODUCTION |  | | Journal (article/letter/editorial) | | weathering of sedimentary parent rocks at Moanda, in Gabon. Manganese concentration through chemical...of manganite crystals. At the same time, manganiferous calcite weathers along twins to manganite crystals...manganiferous calcite, and chlorite weather either into manganite or into a mixture of todorokite + kaolinite. These...ZlEMOUGOtJLA WHEATRERIRG PROFILE ~ gondile b _ THE MOANDA WHEATHERING PROFILE Fig. 1. Sketch of two weathering...Ziemougoula and (b) Mn2+-bearing sedimentary rocks at Moanda. 322 D. NAHON & S. PARC phides which weather |  | | Journal (article/letter/editorial) | | EYLANDT, NORTHERN TERRITORY, AUSTRALIA BERNHARD Department PRACEJUS. of Geology and Geophysics, BARRIE...grade ores at the giant Moanda deposit in Gabon include supergene manganite, pyrolusite and cryptomelane...makes Groote Eylandt an analogue of the Moanda deposit in Gabon. The importance of supergene processes...manganese phases. Though manganese minerals like manganite or vernadite still exist, their origin could be... 94 Moanda, Gabon According to Leclerc and Weber (1980) the superficial manganese ores of Moanda have |  | | Journal (article/letter/editorial) | | e r a i II est possible de distinguer de bas en haut des coupes 6tudi6es (coupes naturelles, puits d'hommes...poissons>> comparable ~ celle qui a 6t6 d6crite/t Moanda au Gabon (Perseil et Bouladon 1971; Nahon et al. 1983)...front d'alt6ration (Fig. 1). On y d6crit de bas en haut: - (i) une unit6 mangan6sif6re inf6rieure d'environ...6t6 d6jfi observ6 dans les gisements africains de Moanda et de Ziemougoula par Beauvais et Nahon (]!985)...qui introduit du potassium dans les solutions en haut de profil. De la m~me fagon l'aluminium lib6r6 par |  | Polgári, M., Hein, J.R., Vigh, T., Szabó-Drubina, M., Fórizs, I., Bíró, L., Müller, A., Tóth, A.L. (2012) Microbial processes and the origin of the Úrkút manganese deposit, Hungary. Ore Geology Reviews, 47. 87-109 doi:10.1016/j.oregeorev.2011.10.001 | Journal (article/letter/editorial) | | Mangán Ltd. Úrkút, Külterület 1, H-8409, Hungary d Department of Mineralogy, Geochemistry and Petrology, University...shale-hosted Mn-carbonate deposits include Moanda, Gabon (Early Proterozoic, 2.095 Ga), Wafangzi, Gaoyan...and composed typically of Carhodochrosite and manganite. Remnants of microbial activity are also common...Molango—Mexico, Okita, 1987; Okita and Shanks, 1988; Moanda—Gabon, Hein et al., 1989; Úrkút—Hungary, Polgári et...exploited ore volume is 436,000 m 3 and an open-pit mine site covered 1.81 km2 (Fig. 6a). The (ii) black |  | | Journal (article/letter/editorial) | | Centre of Advanced Study in Economic Geology, Department of Geological Sciences, Jadavpur University,...L~ngban, Sweden (1900-1750) Franceville Formation, Gabon (c. 2140) Wafangzi, China (Middle Proterozoic) Minas...a transgressive, somewhat euxinic basin at Moanda, Gabon (Franceville Series: c. 2140 Ma) consisting...shale and calcareous siltstones and consists of manganite and Mn-carbonates. In one part of the deposit...the Lukoshi Complex, Zaire, Franceville Series, Gabon; and possibly in the Penganga Beds, India. Most |  | | Report (issue) | | United States of America 1984 CIRCULAR 930-A Department of the Interior WILLIAM P. CLARK, Secretary...compiler), USGS; Ian Goldberg, South African Department of Mineral and Energy Affairs (MEA), Minerals...A. B. T. Werner and Jan Zwartendyk, Canadian Department of Energy, Mines and Resources (EMR), Mineral...of Mines and the Geological Survey of the U.S. Department of the Interior; the Geological Survey and the...the Mineral Policy Sector of the Canadian Department of Energy, Mines and Resources; the Federal Institute |  | | Journal (article/letter/editorial) | | , or higher oxides (pyrolusite, cryptomelane,manganite, psilomelaneetc.), the lowtemperaturesilicates...stablephasesare pyrolusiteand cryptomelane,but manganite,nsutite and birnessitemay alsoform by restrictedoxidationof... (Mn,Ce) Mn$07.2H20(LARSON, 1962) •e. MnOOH MANGANITE HYDROXIDES •' - MnOOH(BRICKER, 1965) FEITKNECHTITE...Ward mine, Dona Ana County,Black Diadepositsdiscussed above, rhodochrosite, generally mond mine, Grand...of minerals of manonly minerals. Hetaerolite,manganite,and chalcophanite occurashypogene veinmineralsat |  | | Report (issue) | | Future Supply Professional Paper 1802–L U.S. Department of the Interior U.S. Geological Survey Periodic...pdf. Cover. Photograph of the Mamatwan open pit mine in South Africa. The black manganese layer is about...folded layering is shown by the shapes of the various mine benches. Lighter material in the background is waste...Paper 1802– L U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior RYAN...............................................L18 Mine Waste Characteristics ......................... |  | | Journal (article/letter/editorial) | | system: Quantitative approach Peter Laznicka Department of Geological Sciences, Universityof Manitoba...51%) evaluated. Correspondence to: P. Laznicka, Department of Geological Sciences, University of Manitoba...lumped together with the output of a larger local mine. The locality registered in the literature is thus...of an orebody (or orebodies). At the old Crimora Mine in Virginia (Eilertsen and Feiss, 1946), "about...credited with 1045 Mn mines. This amounts to one mine per 362 km 2. Canada, on the other hand, has only |  | Molnár, Zsombor, Polgári, Márta, Hein, James R., Józsa, Sándor, Fekete, József, Gyollai, Ildikó, Fintor, Krisztián, Bíró, Lóránt, Szabó, Máté, Rapi, Sándor, Forgó, Péter, Vigh, Tamás (2017) Fe-Mn oxide indications in the feeder and mound zone of the Jurassic Mn-carbonate ore deposit, Úrkút, Hungary. Ore Geology Reviews, 86. 839-855 doi:10.1016/j.oregeorev.2016.11.005 | Journal (article/letter/editorial) | | ore deposit were studied using 45 samples (Úrkút Mine, Shaft III, deep level). Microstructural and textural...built up of Fe-Mn-oxides (ferrihydrite, goethite, manganite, pyrolusite, hollandite, birnessite, hausmannite)...conditions are supported by the formation of a manganite proto-ore produced by aerobic bacterial oxidation...meters to tens of meters thick observable in the mine between the footwall limemarlstone and the ore bed...level of the Úrkút manganese mine, set 5 was collected at the Eplény mine from a similar geologic position |  | | Journal (article/letter/editorial) | | contrast the pisoliths of the upper ore zone at Moanda, Gabon, are concretions of weathering origin (Le Clerc...Broken Hill Proprietary (BHP) Co. Ltd. manganese ore mine is currently rated as the No. 3 producer in the...capacity of 2.4 million tonnes per annum. In 1986, the mine produced 2 million tonnes of manganese of which...pisolitic pyrolusite, suggesting that an earlier manganite may have existed (Champness, 1971 ), and (2) the...trapping sand-size detrital particles, and dense manganite containing no detrital grains. The romanechite |  | | Journal (article/letter/editorial) | | Geology, Istanbul University, Avcilar , Turkey ’ Department of Geology and Geophysics, University of Adelaide...massive forms. Chief ore minerals are pyrolusite, manganite, cryptomelane, rhodochrosite and kutnahorite....than 250 mT of ore) and of this major manganese province. However, while the eastern deposits lie within...mineral in unit 12. Psilomelane/romancheite and manganite are also present in unit 10. Lepidochrosite is...Pisoliths consist dominantly of pyrolusite, and manganite is seen in replacement structures and as a cement |  | | Journal (article/letter/editorial) | | Paleoproterozoic; Uranium; Manganese; Atmosphere; Oklo; Gabon; Carbon isotopes; Black shales 1. Introduction...Introduction The natural nuclear fission reactors in Gabon are unique. The possibility that nuclear fission reactions...Oklo uranium deposit of the Francevillian Series, Gabon (Neuilly et al., 1972). Other uranium deposits of...in the Paleoproterozoic uranium ore deposits of Gabon. This observation raises the question whether this...Mn-deposits in the world, namely the Moanda deposit. Reserves of the Moanda deposits are estimated to be 200 |  | | Journal (article/letter/editorial) | | (Kobe, Japan) . . . . . . . . . . . . . . . . 13 Manganite formation in the first stage of the lateritic...(Poitiers, France) and P. Nziengui-Mapangou (Moanda, Gabon) . . . . . . . . . 25 Yttrium, lanthanum and |  | | Journal (article/letter/editorial) | | rocks and ores contain pyrolusite, cryptomelane, manganite, and braunite. Rocks of the Chitradurga Group...phase, e.g., deposits in Africa (South Africa, Gabon, Ghana, Congo), Brazil, Australia, India, Sweden...medium and large manganese deposits (e.g., Moanda deposit, Gabon) (Weber, 1970). Significant Mn reserves...the Marra Gamba BIF, Hammersley basin, Pilbara province (Western Australia). The weathering profiles of...manganese oxides in the Pilbara manganese ore province (Western Australia) located 400 km SE of Port |  | | Book | | 11. Conclusion 2.2.2. Model Test Area: Moanda Deposit, Gabon, West Africa 2.2.2.1. Introduction 20 20...the Postmasburg Region, Griqualand West, Cape Province, South Africa 3.3.1. Geological Setting 3.3.2...Mn(II)-smectite formation 4.2.1.1.2. Stage of manganite (,-MnOOH) formation 4.2.1.2. Major States of Weathering...(pyrolusite, cryptomelane, 10 A-manganates, etc.) - manganite + Ca rhodochrosite- Ca rhodochrosite + manganocalcites...reflected particularly clearly in the processes of manganite and rhodochrosite 8 Chapter 1 ore accumulations |  | | Book | | ........................ 97 Example of the Moanda (Gabon) Sedimentary Manganese Deposit Enriched by Lateritization...142 Laterites in a Humid Equatorial Climate:the Gabon Example ....... 145 Conclusions and Perspectives...(PE), Brazil DANIEL JEANNETTE SAM CHAUDHURI Department of Geology, Kansas State University Manhattan...carbonates dans les series rouges mesozo·,ques du Haut-Atlas central (secteur de Telouet- lghrem, Maroc)...continentales epigeniques dans le Jurassique moyen du Haut-Atlas central (Maroc) Double signification des palygorskites |  | Ruffet, G., Innocent, C., Michard, A., Féraud, G., Beauvais, A., Nahon, D., Hamelin, B. (1996) A geochronological and study of K-Mn oxides from the weathering sequence of Azul, Brazil. Geochimica et Cosmochimica Acta, 60 (12) 2219-2232 doi:10.1016/0016-7037(96)00080-4 | Journal (article/letter/editorial) | | (Received 13545 Aix-en-Provence Cedex 4, France Department of Geology, University of Washington, July 12...cryptomelane have been already observed at Moanda (Gabon) ( Nziengui-Mapangou, 198 1) , although direct...direct replacement of rhodochrosite by manganite (MnOOH) is more commonly observed. Recent thermodynamic... 1989; Nahon and Part, 1990) have shown that manganite is not stable for high CO* pressures (logfC0,...roches skdimentaires p&ambriennes. Gisements de Moanda (Gabon) et d’Azu1 (BrCsil). Th&se d’Universit& (Poitiers) |  | | Journal (article/letter/editorial) | | 2COMILOG, Service Prospections Ext~rieures, Moanda (Gabon) (Received March 22, 1983; revised and accepted...manganocalcite weather in this chronologic order into manganite. Chlorite is transformed into a mixture of Mn-oxihydroxide...layer of a few centimetres thick, made up of manganite, occurs at the basal portion of the altered profile...the profile in a zone where the first-formed manganite is replaced by secondary Mn-oxides similar to...originates from a possible transformation of manganite. Frondel et al. (1960) have noted the presence |  | Polgári, Márta, Németh, Tibor, Pál-Molnár, Elemér, Futó, István, Vigh, Tamás, Mojzsis, Stephen J. (2016) Correlated chemostratigraphy of Mn-carbonate microbialites (Úrkút, Hungary) Gondwana Research, 29 (1) 278-289 doi:10.1016/j.gr.2014.12.002 | Journal (article/letter/editorial) | | Mangán Ltd, Külterület 1, Úrkút 8409, Hungary f Department of Geological Sciences, University of Colorado...Corresponding author. ⁎⁎ Correspondence to: S.J. Mojzsis, Department of Geological Sciences, University of Colorado... Molango, Mexico — Okita and Shanks, 1988; Moanda, Gabon — Hein et al., 1989; Postmasburg, Southwest...(rhodochrosite, smectite, celadonite, siderite, manganite, goethite, hematite) and isotopic characteristics...traces of barite, chlorite, zeolite, feldspar, and manganite. The black shale host consists of quartz, calcite |  | | Journal (article/letter/editorial) | | (carbonatezone) Molango GrooteEylandt (carbonatezone) Moanda ? Chamberlain (Gregory Member) pear to be early...At Acoxcatlan,6 km to the west,an inactivepilot mine exposesa differentfaciesof ore, here only 1.5 m...(Fig. 16) goingup section.This correspondsto Moanda, Gabon rhodochrosite + kutnohorite (CaMn(COs)2), folOre...replaced.In their originalstate,they strates.At Moanda,depositionof carbonateandsili- 106 E. R. FORCEAND...authigenicsilica,montmorillonite,zeolite; 4 = manganite,pyrolusite,"psilomelane,"zeolites,glauconite,iron |  | | Journal (article/letter/editorial) | | in manganese duricrusts in which the sequence manganite pyrolusite - cryptomelane is observed (Weber e... According to hydration reactions, goethite, manganite and gibbsite are hydrated minerals while hematite...mangan6sif'eres successives dans le gisement de Moanda (Gabon). Sci. G6ol. Bull., 32: 147-164. |
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Moanda Mine, Moanda, Léboumbi-Leyou Department, Haut-Ogooué Province, Gabon