| | Journal (article/letter/editorial) | IN WEATHERED PYROCHLORE-GROUP MINERALS FROM THE LUESHE AND ARAXÁ (BARREIRO) CARBONATITES BY 57Fe MÖSSBAUER...from two Nb ore deposits in laterite: Lueshe in the Democratic Republic of Congo, and Araxá in Brazil. In...oxidation state in the kalipyrochlore sample from Lueshe. Spectra of both samples are consistent with the...coordinated by 6 O2– is observed in both cases. In the Lueshe sample, it is also coordinated by 5 O2– and 1 OH–...gisements latéritiques à Nb, celui de Lueshe en République Démocratique du Congo et celui d’Araxá au Brésil, l’idée | | | Journal (article/letter/editorial) | Mineralogy andgeochemistry of theLueshe deposit, Kivu, BelgianCongo... 734 Geochemical characterof ca...geochemical study of carbonatitesamplesfrom Lueshe,Kivu, Belgian Congo,by the combinedX-ray diffraction-flu...discoveringa niobium-bearingcarbonatitein Kivu, Belgian Congo. INTRODUCTION TEE ore minerals of nlobium...from the niobium-bearing carbonatiteof Lueshe,Kivu, Belgian Congo. characterized by a markedimpoverishment...typesof carbonatites. The simple carbonatiteof Lueshe, Kivu occursin the graben area where severalnephe | | | Journal (article/letter/editorial) | Pyrochlore from weathered carbonatite at Lueshe, Zaire F. WALl.,C. T. WILLIAMS,A. R. WOOIJ.EY Department...study of weathered pyrochlore in the laterite above carbonatite at Lueshe, NE Zaire, has been made in order...variations. Pyrochlore in fresh carbonatite at Lueshe is close to an ideal formula of (Ca,Na)2Nb206(OH...worldwide. As a result weathered pyrochlore at Lueshe has a large apparent A cation deficiency with A...remain stable. Abundant kalipyrochlore is unique to Lueshe and is thought to be related to the abundance of | | | Journal (article/letter/editorial) | Keywords: Carbonatites Niobium ore deposits Pyrochlore Laterite Supergene ores a b s t r a c t This work reviews...Similar supergene occurrences occur at Lueshe and Bingo (D.R. Congo), Mabounié (Gabon), Sukulu (Uganda)...date, all major operating and former (Oka, Fen, Lueshe) Nb mines have been developed in primary carbonatites...only operating Nb mine in under-saturated peralkaline syenites is the Karnasurt mine (Kremenetsky et al...units presents in carbonatites e.g. the Loolekop mine at Phalaborwa (Fig. 250 of Woolley, 2001), Catalão-I | | | Journal (article/letter/editorial) | meteoric alterations of the Lueshe carbonatite complex žDemocratic Republic of Congo / identified by a REE...whole-rock samples of the Lueshe carbonatite complex ŽNE of Democratic Republic of Congo.. The fresh and hydrothermally...fluorhydric-nitric solution ŽHF q HNO 3 .. The Lueshe carbonatite complex contains a suite of REE-carriers...Meteoric weathering; Rare-earth elements; Republic of Congo 1. Introduction Among the chemical characteristics...and florencite. The REE can also concentrate in laterite profiles formed on carbonatite 0009-2541r00r$ | | | Journal (article/letter/editorial) | exchangefor K, Sr, and Ba is a feature of samplesfrom laterite horizons overlying carbonatites. In most casesfJ...rock type Brevik, Norway; nephelinesyenite Lueshe, Lake Kivu, Zaire; carbonatite Hybla, Ontario, Canada;...Panda Hill, Mbeya, Tanzania; carbonatite Woodcox mine, Hybla, Ontario; granitic pegmatite MacDonaldmine...Leushe, Lake Kivu, Zaire; carbonatite Fredricksvarn,NoMay; nepheline syenite Lueshe, Lake Kivu, Zaire; carbonatite...carbonatite Lueshe, Lake Kive, Zaire; carbonatite Jacupiranga,Sao Paulo, Brazil; carbonatite Araxe, Minas | | | Journal (article/letter/editorial) | discoveryof pyrochlore in carbonatites (Arax/t, 1947; Lueshe,1956) whichset up columbiumas one of the major...major depositsand especially Messrs.Bradford,A. Burne,Dr. de Neve, Major Farrington,Dr.Ing. Hermann, Messrs...The writer is indebted to Dr. Charles H. Behre,to Dr. RichardH. Jahnsand Dr. KennethBurke who kindly...deposits f. marine 8. Sediments a. clays, kaolins b. laterite, bauxite Order of Importanceof the Various Occurrences:...diathreme. Internal StructureoI ColumbiumCarbonatites.-Lueshe: 1. core of busorite (canefinite syenite) 2. intermediatering | | | Journal (article/letter/editorial) | carbonatites at Argor, Carillon Dam, Chilwa Island, Fen, Lueshe, Oka, Mbeya, Meech Lake and Verity. Primary features...e veinlets and low A-ion totals (Carillon Dam, Lueshe, Myeba). K EY WORDS : zoned crystals, carbonatites...oxidized to Ce4+ in some pyrochlore from laterite (e.g. Lueshe and Mbeya of this paper; see below) it is...pyrochlore pyrochlore,uranpyrochlore Mineral Lueshe, Dem. Rep. of Congo San Vicente, Cape Verde Is. Kovdor,...7), ceriopyrochlore (Lueshe specimen BM 1966/232 – rim) and kalipyrochlore (Lueshe specimen BM 1966/232 | | | Journal (article/letter/editorial) | (Coetzee and Edwards, 1959). Not only are carbonatite laterite regoliths recognized as a unique ore-concentration...hematite and goethite and rare uorite. Below the laterite is a ferrocarbonatite transitional zone which...margins of the carbonatite centre. The uppermost laterite zone varies from a central depth of 70 m (BRL-1)...carbonatites elsewhere in Africa (e.g. Lueshe, Democratic Republic of the Congo), the Buru carbonatite centre...weathered crusts. It also has been reported from the Lueshe carbonatite complex, where it was observed to be | | | Journal (article/letter/editorial) | 8 , * ~ 0 . 2 , w = 0 and 0 . 2 < n < l ) from Lueshe, Zaire is a defect pyrochlore species whose A-site...refinement, powder pattern I. INTRODUCTION The Lueshe cancrinite syenite/carbonatite complex is located...Zaire, about 40 km south-west of Edward lake. The laterite surrounding this complex is a niobium deposit...pyrochlore subgroup, from the residual soils of the Lueshe carbonatite deposit. The calculated density is...London show that the kalipyrochlore from the Lueshe deposit (Kivu, Zaire) has a formula lying between the | | Torró, L., Villanova, C., Castillo, M., Campeny, M., Gonçalves, A. O., Melgarejo, J. C. (2012) Niobium and rare earth minerals from the Virulundo carbonatite, Namibe, Angola. Mineralogical Magazine, 76 (2) 393-409 doi:10.1180/minmag.2012.076.2.08 | Journal (article/letter/editorial) | ~47% Fe 2+ in secondary pyrochlore from the Lueshe mine in Congo. However, the total amount of iron, Fet...hydrothermal alteration were described at Lueshe mine in Congo by Nasraoui et al. (1999) and Nasraoui and...Uganda (Williams et al., 1997), the Lueshe carbonatite in Congo (Nasraoui et al., 1999; Nasraoui and...position of the pyrochlore in the lateritic profile. At Lueshe, moreover, Ba- and Srbearing pyrochlore is found...da Universidade Agostinho Neto (Luanda, Angola). Dr Xavier Llovet assisted in the preparation of EPMA | | Melgarejo, Joan C., Costanzo, Alessandra, Bambi, Aurora C.J.M., Gonçalves, Antonio O., Neto, Andrés B. (2012) Subsolidus processes as a key factor on the distribution of Nb species in plutonic carbonatites: The Tchivira case, Angola. Lithos, 152. 187-201 doi:10.1016/j.lithos.2012.06.024 | Journal (article/letter/editorial) | set of faults oriented NE–SW that cut the Angola–Congo craton (Issa Filho et al., 1991). Different types...systems, such as in a weathering profile in Lueshe, Congo (Wall et al., 1996). Oliveira et al. (2007,...studies in Barcelona were supported by an AECI grant. Dr. Xavier Llovet helped during EPMA analyses at the...Científico-Tècnics, Universitat de Barcelona. A. Crespi and Dr. J. Rius acquired in situ X-ray microdiffraction...Serveis Científico-Tècnics, Universitat de Barcelona (Dr. Tariq Jawhari) and at Earth and Ocean Sciences, | | Giovannini, Arthur L., Bastos Neto, Artur C., Porto, Claudio G., Pereira, Vitor P., Takehara, Lucy, Barbanson, Luc, Bastos, Pedro H.S. (2017) Mineralogy and geochemistry of laterites from the Morro dos Seis Lagos Nb (Ti, REE) deposit (Amazonas, Brazil) Ore Geology Reviews, 88. 461-480 doi:10.1016/j.oregeorev.2017.05.008 | Journal (article/letter/editorial) | (1) pisolitic laterite, (2) fragmented laterite, (3) mottled laterite, (4) purple laterite, (5) manganiferous...manganiferous laterite, and (6) brown laterite. All the laterites are composed mainly of goethite (predominant...resulting in goethite formation. In the manganiferous laterite (10 m thick), the manganese oxides (mainly hollandite...in the pisolitic type to 3.50 wt.% in the brown laterite. HREE concentration is very low. 1. INTRODUCTION...rise. The average Nb abundance in the Earth’s laterite is 8 ppm (Rudnick and Gao, 2003). Nb is concentrated | | Geisler, T., Berndt, J., Meyer, H.-W., Pollok, K., Putnis, A. (2004) Low-temperature aqueous alteration of crystalline pyrochlore: correspondence between nature and experiment. Mineralogical Magazine, 68 (6) 905-922 doi:10.1180/0026461046860230 | Journal (article/letter/editorial) | Nb; Hogarth, 1977) from Lueshe near Lake Kivu of the Democratic Republic of Congo obtained from the Mineralogical...sample is not from a carbonatite host rock of the Lueshe alkaline complex, because Ta-rich pyrochlore does...2001). In a study of natural pyrochlore from the Lueshe complex, Nasraoui and Bilal (2000) presented electron...occurrence of kalipyrochlore in Lueshe in the Democratic Republic of Congo (Ercit et al., 1994; Nasraoui...variation in pyrochlores from the Mt Weld carbonatite laterite, Western Australia. Mineralogy and Petrology, | | | Journal (article/letter/editorial) | Kola Peninsula (Subbotin and Men'shikov, 1987) and Lueshe, Zaire (Mitchell, 1996). Most other descriptions...ridge surrounded by lowlands, and from the east and north-east, by the Segozero Lake. The ridge is forested...mineral compositions: Khibina loparite (LREE), Lueshe lueshite (Na, Nb), Magnet Cove perovskite (Ca,...number of carbonatite localities including the Lueshe complex, Zaire (Wall et al., 1996), Mt. Weld, Australia...Compositional data on secondary monazite found in the laterite crests covering carbonatite deposits, are limited | | | Journal (article/letter/editorial) | Enrichment of Al, LOI, Cr, Cu, and V occurred in the laterite horizon, while enrichment of Al, LOI, Ba, Ce,...Elsevier Science B.V. All rights reserved. Keywords: Laterite; Bauxite; Element mobility; Basalt weathering;...biological parameters. Specific conditions leading to laterite formation have been documented previously ŽGrubb...factors in determining the extent and grade of laterite formation. 0009-2541r00r$ - see front matter...distinct stages in the alteration of parent rock to laterite, thought to have been brought about by circulation | | | Journal (article/letter/editorial) | Wolframite Ores from Democratic Republic of the Congo, Africa Alireza K. Somarin Department of Geology...various location in Democratic Republic of the Congo shows that cassiterite and wolframite ores from...the eastern portion of the Democratic Republic of Congo (DCR). With the advent of U.S. Securities and Exchange...deposits: A good example of this type deposit is Lueshe Nb deposit, in the northeast DRC (Figure 2). This...Catalao, Brazil; Tomtor, Russia; Lueshe, Democratic Republic of Congo Alkaline granite and syenite Nb | | | Journal (article/letter/editorial) | Formation of interbasaltic laterite horizons in NE Ireland by early Tertiary weathering processes I....MEIGHAN, L G. 2001. Formation of inter basaltic laterite horizons in NE Ireland by early Tertiary weathering...lie two laterite horizons known as the Port na Spaniagh laterite (PSM) and the Ballylagan laterite (BLM)...divided into three distinct units based on the two laterite horizons (Patterson, 1955; Old, 1975): the Lower...quarries, cuttings, coastal exposures and disused mine workings, were taken mainly Proceedings of the Geologists' | | | Journal (article/letter/editorial) | of the central African mega-unit, made up of the Congo, Kasai and Angolan cratons (Goodwin, 1996). The...values close to 0 wt.% have also been found in the Lueshe carbonatites (Nasraoui and Bilal, 2000). Betafite...particular Dr C.T. Williams for the assistance received at the Natural History Museum in London. Dr Xavier...variation in pyrochlores from the Mt. Weld carbonatite laterite, Western Australia. Mineralogy and Petrology,...(2000) Pyrochlores from the Lueshe carbonatite complex (Democratic Republic of Congo): a geochemical record | | | Journal (article/letter/editorial) | secondary apatite and muscovite. K EY WORDS : bauxite, laterite, weathering, geochemistry, mineralogy, trace elements...deposits of the Middle Timan are located in the North of European Russia, between the NE edge of the Russian...widespread and it has been identi ed in many karst and laterite deposits (Bárdossy, 1982; Bárdossy and Aleva...group minerals are very common in both karst and laterite bauxite environments. According to Gaines et al...weathered part of the pro le over carbonatites at Lueshe, Zaõ¨re. Although a similar intergrowth was not | | | Journal (article/letter/editorial) | documented only in altered samples (kalipyrochlore) from Lueshe with possible accommodation in the A-site (Nasraoui...(Eds.), Phoscorites and Carbonatites from Mantle to Mine: The Key Example of the Kola Alkaline Province....variation in pyrochlore from the Mt Weld carbonatite laterite, Western Australia. Mineralogy and Petrology 38... Pyrochlores from the Lueshe carbonatite complex (Democratic Republic of Congo): a geochemical record...in weathered pyrochlore-group minerals from the Lueshe and Araxá (Barreiro) carbonatites by 57Fe Mössbauer | | | Journal (article/letter/editorial) | geographically separated areas, comprising the Shaba and Kivu provinces west of the Central African Rift and...In the west, the Kibara belt is limited by the Congo (Zaire) craton (although the border area is not...occurrences are known from Greenland, Scandinavia, India, Congo and Australia. Towards the later middle Proterozoic...of collision belts are the Grenvillean belts of North America and western South America, the Albany-Fraser...1986; Pinna et al., 1993:950-800 Ma). Towards the North, however, Mozambiquian collision is younging (in | | | Book (edition) | localities as inclusions in the limestone”’ (italics mine). Actually, the first published description of...‘‘fine-grained but crystalline,” (5) that they were 1] thank Dr. G. R. Udas for bringing this historic description...carbonatite dikes cutting the kimberlite of the Premier mine (p. 542) he classed as magmatic, but 1 Bowen admitted...G. B. Du Bois (1956, 1959), B. C. King (1949). Congo (Belgian): A. Meyer and P. de Bethune (1958, 1960)...) around a “core” of alkalic silicate rock: Lueshe, Congo, and Chishanya, Southern Rhodesia. In some cases | | | Journal (article/letter/editorial) | 13.5 21.5 27.8 Okorusu 8.2 0.2 2.7 2.7 32.7 4.9 Lueshe 4.4 2.8 64.6 0.8 17.9 0.8 Sarfartôq 78.5 1.0 1...Greenland carbonatites (Bell and Simonetti 2010) North American carbonatites (Bell and Simonetti 2010)...in millimetres (d) Pyrochlore concentrate, Niobec Mine, Quebec, Canada; scale in millimetres. forming...and 23 (a); e.g. Catalão, Brazil; Lueshe, Democratic Republic of Congo; and St. Honoré, Oka, and Aley,...exceptions are the Siilinjärvi mine, Finland (O’Brien et al. 2015), and Cajati mine, Jacupiranaga Complex, Brazil | | | Journal (article/letter/editorial) | Chuktukon massif, Chadobets upland, Krasnoyarsk territory, in Shchelochoni magmatizm Zemli, (Alkaline Magmatism)...variation in pyrochlore from the Mt. Weld carbonatite laterite, Western Australia, Mineral. Petrol., 1988, vol... Pyrochlores from the Lueshe carbonatite complex (democratic republic of congo): a geochemical record...Nasraoui, M., Pyrochlore from weathered carbonatite at Lueshe, Zaire, Mineral. Mag., 1996, vol. 60, pp. 731–750 |
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