 | | Journal (article/letter/editorial) | | lateritic weathering of organic shales with rhodochrosite and phyllosilicates (mainly muscovite) has led...reserves with 42.65% Mn). The oxidation of the rhodochrosite-rich levels produces ore that typically breaks...corresponds to a sequence of transformation (rhodochrosite ~ cryptomelane nsutite ~ pyrolusite) by pseudomorphic...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) |  | 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) | | 3COMILOG, Service Prospections Extdrieures, Moanda (Gabon) (Received June 23, 1982; revised and accepted...whereas in a weathered carbonate sequence (Moanda, Gabon) manganite replaces thodochrosite. In both areas...tephroitites. The second is the minefield of Moanda in Gabon where the weathering profile overlies Precambrian...CARBONATE ROCKS OF MOANDA (GABON) The l>recambrian parent-rock of the Moanda minefield is a black...the base of oxidized profiles, is enriched in rhodochrosite which comes from the subaerial alteration of |  | 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) | | profiles in Africa and Brazil are the following: rhodochrosite + illite - cryptomelane * kaolinite - nsutite...on manganiferoussedimentary rocks in the Moanda area (Gabon), and in the Azul area (northern Brazil)...The second profile occurs at the Moanda weathering ore-body, in Gabon. The Precambrian sedimentary parent...a black calcareousshale consisting of 560/o rhodochrosite, 23o/oillite, 11olodetrital silt-sized quartz...with in some places,a direct transition from rhodochrosite to cryptomelane. The third example is that of |  | | Journal (article/letter/editorial) | | weathering of sedimentary parent rocks at Moanda, in Gabon. Manganese concentration through chemical...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...sulphides occuring at the same time and goanda area (Gabon) decreasing strongly the pH. At the same level of...Moanmanganiferous calcite transformations, is replaced by da in Gabon where the weathering profile, which is birnessite |  | | Journal (article/letter/editorial) | | EYLANDT, NORTHERN TERRITORY, AUSTRALIA BERNHARD Department PRACEJUS. of Geology and Geophysics, BARRIE...example, the highest grade ores at the giant Moanda deposit in Gabon include supergene manganite, pyrolusite...makes Groote Eylandt an analogue of the Moanda deposit in Gabon. The importance of supergene processes...manganiferous calcareous silstone (Mn-minerals are rhodochrosite and manganocalcite). Recent K/Ar-dating of glauconite... 94 Moanda, Gabon According to Leclerc and Weber (1980) the superficial manganese ores of Moanda have |  | | Journal (article/letter/editorial) | | ACCOMPANYING PHASES IN A LATERITIC PROFILE OF MOANDA, GABON M. AMOURIC,I S. PARC,2 AND D. NAHON2 I...mixtures of manganite and pyrolusite from the Moanda sequence (Gabon) were examined by HRTEM in an effort to...manganiferous sedimentary rocks in the Moanda minefield, Gabon. A global cross section of this profile...black calcareous shale, made up of about 56% rhodochrosite, 23% illite, 11% detrital silt-size quartz,...Petrographically, the boundary between the rhodochrosite-bearing rock and this manganite-pyrolusite layer |  | | Journal (issue) | | write to: Treasures of the Earth, Back Issues Department, De Agostini (UK) Ltd, PO Box 1, Hastings TN35...Tephroite, Zinnwaldite GROUNDWORK On the Mineral Trail: Gabon DISCOVERY Red chalk INDEX Index This is the final...write to. Treasures of the Earth, Back Issues Department, Gordon & Gotch Ltd, Private Bag 290, Burwood...write to: Treasures of the Earth, Back Issues Department, Netlink Distribution Co, Private Bag 47-906...write to: Treasures of the Earth, Back Issues Department, Republican News Agency, PO Box 101, Maraisburg |  | De Putter, Thierry, Liégeois, Jean-Paul, Dewaele, Stijn, Cailteux, Jacques, Boyce, Adrian, Mees, Florias (2018) Paleoproterozoic manganese and base metals deposits at Kisenge-Kamata (Katanga, D.R. Congo) Ore Geology Reviews, 96. 181-200 doi:10.1016/j.oregeorev.2018.04.015 | Journal (article/letter/editorial) | | East Kilbride, United Kingdom Ghent University, Department of Geology, Mineralogy and Petrology, Krijgslaan...Manganese Field (hereafter 54 KMF), the Moanda deposits of Gabon and the Serra do Navio deposit in Brazil...Kisenge-Kamata area is located in the former Katanga province, 250 km west of 67 Kolwezi (Fig. 1a). Geologically...1973). In the region of Mwene Ditu (Kasai Oriental Province, ~400km 91 North of Kisenge; Fig. 1a), where...such as Mwene Ditu (Fig 1; Kasai Oriental 128 Province; Morelli & Raucq, 1961), for which an E-W elongated |  | | Journal (article/letter/editorial) | | do Mina and other deposits are as follows: rhodochrosite, manganocalcite, tephroite, spessartine, rhodonite...phase, e.g., deposits in Africa (South Africa, Gabon, Ghana, Congo), Brazil, Australia, India, Sweden...high bioproductivity, which accumulated the rhodochrositebearing car bonaceous shales (ampelites). Their...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 |  | 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...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...lithostratigraphy (b) of the Mn carbonate ore bed (Úrkút Mine, Shaft No. III, + 180 m) (c) A–A and B–B sections |  | | Journal (article/letter/editorial) | | shadedareamayexceedsaturationwith respectto rhodochrosite. (b). Valuesof Eh andpH (afterCannonandForce...(carbonatezone) Molango GrooteEylandt (carbonatezone) Moanda ? Chamberlain (Gregory Member) pear to be early...edeposition(e.g., laminated shallow-marine rhodochrosite-pyrite deposits). This variation treats the... ulated tiny Astarte bivalves (replaced by rhodochrosite)is presentin pyrite-rich rock 6 to 9 m abovethe...At Acoxcatlan,6 km to the west,an inactivepilot mine exposesa differentfaciesof ore, here only 1.5 m |  | | 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) | | r e than 20%) consist of manganocalcite and rhodochrosite and, to a lesser degree, manganoankerite and...carbonate ores consist of manganoankerite, rhodochrosite, and manganosiderite; they usually contain 1...(Mn content from 19 to 38%), consisting of rhodochrosite ( 2-99%), spessartine (4-35%), rhodonite (0-40%)...of the Okonja River and in the vicinity of the Moanda deposit. At the base of the Franceville Series...intergrowth of dolomite and carbonaceous material. Rhodochrosite is confined to fine intercalations of silty |  | 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..., 1987) The parent rock is composed of 65% rhodochrosite, 15% phyllosilicates, 10% quartz, 5% feldspars...feldspars, and 5% sulfides. The rhodochrosite consists of “egg-fish” shaped micronodules of tiny crystals (210...the shale. The chemical composition of the rhodochrosite, Isotopic FIG. 2. Chemical triangular diagram...( 100-200 pm), in association with veins of rhodochrosite. Phyllosilicates are detrital grains of muscovite |  | | 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 |  | | Catalog/List | | the surface. 2tX1tx1", £2.50p 3. ALTAITE. Hilltop Mine, Dona Ana Co., New Mexioo, U.S.A. ·Rich tarnished...Specimen B: 1~·x1i", £3.25p 5. APATITE. Carrock Mine, Car~ck Fell, Cumberland. Lustrous bright greenish...1tx1t", £2.50p 6. APATITE variety FRANCOLITE. Levant Mine, Pendeen, Cornwall. Fine lustrous golden brown sharp...Pyrites. 2tx2tx1t", £11.00 10. AURICHALCITE. 79 Mine, Gila CO' I Arizona, U.S.A. Very attractive turquoise-blue...matrix. 2x1fx1%-", £4.5Op 17. 8ORNITE. Dolcoath Mine, Camborne, Cornwall. Rich attractive irridescently |  | | Report (issue) | | panting-dog days. Durangite, 2.7 cm, from the Barranca mine, Coneto de Comonfort, Durango, Mexico. Arkenstone...Budd photo. Durangite, 1.7 cm, from the Barranca mine, Coneto de Comonfort, Durango, Mexico. Arkenstone...see in the Mineralogical Record a brief report of mine from the new New York City Metro Show, which happened...the type locality for the species, the Barranca mine, Conete de Comonfort, Durango, Mexico. At this point...Barite, 4.7 cm, from the Muzo mine, Vasquez-Yacobi district, Boyaca Department, Colombia. Andy Seibel Minerals |  | | Journal (article/letter/editorial) | | deepestpart of the epithermal zone, rhodonite, rhodochrosite,and alabandite, all containing manganesein the...manganesemineralsare mainly characterizedeither by carbonates(rhodochrosite), or higher oxides (pyrolusite, cryptomelane...sedimentsare generally representedby recrystallized rhodochrosite bodies. The mixed sedimentsof carbonatesand...metamorphicequivalentassemblage of spessartite-rhodonite-rhodochrosite-tephroite and other manganese pyroxenesand amphiboles...recentdepositsforming apronsin deposits,Hokkaido,Japan,rhodochrosite, rhodonite thermalspringsites (Hewett and Fleischer |  | | 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 |  | | Catalog/List | | specimen •. 2x2xl". £6.00. 10. BARYTES. wetgrove Mine,Aysgarth, Yorkshire.Specimen A:Select lustrous creamy-white...2i;xHxl". £13.00. 2 12. BoTALLACKITE. Levant Mine, Pendeen, Cornwall. Specimen A: Light green lustrous...in plac8s. 4x1ix1t", £7.00 14. CALCITE. Black~ene Mine, Weardale, Co. Durham. Select creamy translucent...specimen. 32-x2 x1f..", £7.00 15. CARNOTITE. Gould Mine, Fall River Co., S. Dakota, U.S.A. Bright yellow...4tx3x2" r " £14.00 24. CHALCoPYRlrnE. ~~. Wellington Mine, small sharp crystals to 3 mm in 2tx1tx1", £1. SOp |  | | 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 |  | 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...thick black shale. Mineralogical compositions (rhodochrosite, smectite, celadonite, siderite, manganite,...clay marlstone and dark-gray to black shale. Rhodochrosite beds conformably overlie middle Lias (lower |  | | Journal (article/letter/editorial) | | Geology, Istanbul University, Avcilar , Turkey ’ Department of Geology and Geophysics, University of Adelaide...minerals are pyrolusite, manganite, cryptomelane, rhodochrosite and kutnahorite. In thin and polished sections...than 250 mT of ore) and of this major manganese province. However, while the eastern deposits lie within...samples, in most ores consisting dominantly of rhodochrosite, using a VG 602 mass spectrometer (Table 4)...4). The fractionation of C in rhodochrosite relative to phosphoric acid at 25”C, was considered to be approximately |  | 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...transformations, such as formation of early diagenetic rhodochrosite. The large mass of bacteria living in and on...interfinger with black shale (Bs3-4). The Ca-rhodochrosite ore is composed of alternating grey, green,...Németh et al., 1980). Fine-grained (1-2 m) rhodochrosite rock lacks coarse detritus and is laminated...meters to tens of meters thick observable in the mine between the footwall limemarlstone and the ore bed |  | | Catalog/List | | �tb 5) BARYTE and CHALCOPYRITE. Mount Wellington Mine, Twelveheads, Cornwall. Two composite tarnished...6) BARYTOCALCITE. 2"' Sun Vein, Nentsberry Haggs Mine, Nenthead, Cumberland An 80x60mm flat area on limestone...xls. 65x50x30mm. £75. 8) CALCITE on QUARTZ. Geevor Mine, St Just, Cornwall. A single composite terminated...60x55x30mm. £22. IO) CASSJTERlTE and SCHORL. Balleswidden Mine, St Just, Cornwall. A good heavy veinstone witl1...60x40x30mm. £18. 14) CHILDRENITE. George and Charlotte Mine, Tavistock, Devon. A 60x20mm area on veinstone matrix |
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Moanda Mine, Moanda, Léboumbi-Leyou Department, Haut-Ogooué Province, Gabon