 | | Journal (article/letter/editorial) | | of Newcastle, New South Wales, Australia, 2Broken Hill Proprietary Company Limited, Central Research Laboratories...August 4, 1987; accepted October 22, 1987 Summary Pyrochlore is present as a residual mineral within a Mesozoic-Cainozoic...Leaching of the A-site ions Na and Ca from the pyrochlore structure occurred during weathering and the...which were subsequently filled by Fe 3+. The pyrochlore mineral chemistry changes markedly with depth...weathering profile and the sequence: Na-Ca pyrochlore, strontian pyrochlore, strontiopyrochlore, ceriopyrochlore |  | 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) | | Available online 28 June 2012 Keywords: Carbonatite Pyrochlore Niobium Magmatic Hydrothermal Supergenic a b...Tchivira carbonatites contain several pyrochlore generations. Rare pyrochlore crystals, close to the fluorcalciopyrochlore...carbonates and fluorite are also common. Distinct pyrochlore compositions are characteristic for each altered...Pb-pyrochlores and Nb-rich rutile replace earlier pyrochlore generations and are present as inclusions in...hydrothermal minerals. Textural evidences indicate that pyrochlore and these minerals are produced by precipitation |  | | Book (edition) | | petrologists as those of the undersaturated alkalic group—the nepheline syenites and their relatives. Rare...localities as inclusions in the limestone”’ (italics mine). Actually, the first published description of...most of the field work on the Iron Hill complex of Gunnison County, Colorado, in 1912-1913. Although his...accepted the idea of an igneous origin for the Iron Hill carbonatite. In 1924 Bowen, who had visited the...carbonatite dikes cutting the kimberlite of the Premier mine (p. 542) he classed as magmatic, but 1 Bowen admitted |  | | Journal (article/letter/editorial) | | composition of the replaced mineral. At Rubicon Mine, Karibib, a narrow marginal zone of mangantantalite...replacement. Introduction MICROLITE minerals of the pyrochlore-group have been analysed with the electron microprobe...microlite and a uranmicrolite as defined by the I M A Pyrochlore Subcommittee (Hogarth, 1977) have been analysed...has been observed in barium pyrochlore ('pandaite') from Mrima Hill, Kenya, by Harris (1966). A detailed...The composition of an ideal mineral of the pyrochlore group may be represented by the general f o r m |  | | Journal (article/letter/editorial) | | xxxx Keywords: Carbonatites Niobium ore deposits Pyrochlore Laterite Supergene ores a b s t r a c t This...deposit is unique with respect to the varieties of pyrochlore present; extent of replacement by other minerals;...units of carbonatite contain distinct suites of pyrochlore. Bulk rock analysis for Nb gives no indication...and physical concentration of resistant primary pyrochlore. Intense lateritization results initially in...pyrochlores, and ultimately complete decomposition of pyrochlore and formation of Nb-bearing rutile, brookite |  | | Journal (article/letter/editorial) | | considered for potential coproduction of Ta and Nb. Pyrochlore (Nb–Ta), columbitetantalite (Nb–Ta), wodginite...% from tin slag refining and 10 % from secondary mine concentrates. Due to rapid industrialisation and...Canada account for about 92 and 7 % of Nb world mine production, respectively. Since the bulk of the...Economically, significant deposits of Ta and Nb contain pyrochlore, columbite-tantalite, fersmite, loparite and...Tantalum . Rare-elements . Strategic metals . Pyrochlore . Columbite . Tantalite Introduction Tantalum |  | | Journal (article/letter/editorial) | | nepheline–syenite (Zozulya et al., 2007). In the former, pyrochlore is only of mineralogical interest, GEOLOGY OF...Baerzhe; (35) Bonga; (36) Kaluwe; (37) Mrima Hill; (38) Panda Hill; (39) Oka; (40) Araxa; (41) Catalão I;...Fir Chuktukon Toongi Baerzhe Bonga Kaluwe Mrima Hill Panda Hill Oka Araxa Catalão I Catalão II Salitre Tapira...noted that pyrochlores constitute a quite large group of mineral species represented by niobates of complex...cations and anions (Atencio et al., 2010). This group includes multiple representatives and some newly |  | Chakhmouradian, Anton R., Reguir, Ekaterina P., Kressall, Ryan D., Crozier, Jeremy, Pisiak, Laura K., Sidhu, Ravinder, Yang, Panseok (2015) Carbonatite-hosted niobium deposit at Aley, northern British Columbia (Canada): Mineralogy, geochemistry and petrogenesis. Ore Geology Reviews, 64. 642-666 doi:10.1016/j.oregeorev.2014.04.020 | Journal (article/letter/editorial) | | Carbonatite Metasomatic rocks Pyrochlore-group minerals Columbite-group minerals Fersmite Trace-element...Devonian. Primary Nb mineralization consists of pyrochlore (commonly comprising a U–Ta-rich and F-poor core)...discrete crystals and replacement products after the pyrochlore. These phases and associated heavy minerals (apatite...thickness. Fractionation of copious amounts of pyrochlore is reflected in the chemical composition of the...extensive dolomitization, replacement of the pyrochlore and ferrocolumbite by fersmite, and development |  | | Journal (volume) | | chemistry 17 Pyrochlore 18 Sphene 19 Zircon 19 Petrogenesis References ii Ilomba Hill from the Songwe...Photomicrograph of sphene-pyrochlore-aegirine rock showing metamict aegirine rims round pyrochlore crystals 16 15...15 5 Radiometric map of the summit area, Ilomba Hill 16 TABLES 1 2 3 4 5 6 7 Geological history of...pyrochlorebearing pyroxeni te l 7 Analyses of uraniferous pyrochlore from the Ilomba Alkaline Complex and related...source of uranium and niobium is uraniferous pyrochlore (c. 12.5% U 3 0 8, 53 % Nb 20 5 ) which, with |  | | Journal (article/letter/editorial) | | carbonatites and peralkaline igneous rocks. Columbite-group minerals (CGM) account for the majority of the current...as tapiolite, wodginite, ixiolite, rutile and pyrochlore-supergroup minerals are of minor importance....(mainly Rwanda and the DR Congo), around the Kenticha mine (Ethiopia) and in the Alto Ligonha Province (Mozambique)...Nigeria Rwanda Africa total World mine production % Africa/world Ta mine production 2008 2009 2010 2011...deposits are members of the columbite-tantalite group (CGM), followed by tapiolite, ixiolite, wodginite |  | | Book | | Ercit (with 21 Figures) . . . . . . 3 27 Pyrochlore Group Minerals from the Qaqarssuk Carbonatite Complex...fractures in altered greenstones from San Benito County, California, is reported with 20.57 wt.% RE2 0...International Mineralogical Association (IMA). A group name, bastnaesite, for instance, is proposed for...element to the group name: bastnaesite-(La), bastnaesite-(Y) etc. Table 1 gives these group names with the...the different predominating elements. Table 1. Group names ofrare-earth minerals Halides Fluocerite |  | | Report (issue) | | Survey has produced this volume to describe a select group of mineral commodities currently critical to our...antimony in China; niobium in Brazil; and platinum-group elements in South Africa and Russia), thus increasing...same commodities. Rare-earth elements and platinum-group elements particularly are broadly viewed as critical...lithium (Li), manganese (Mn), niobium (Nb), platinum-group elements (PGE), rare-earth elements (REE), rhenium...........................M1 Chapter N. Platinum-Group Elements By Michael L. Zientek, Patricia J. Loferski |  | | Book | | extreme chemical coherence of the rare earth element group, which makes separation of the individual members...lutetium (atomic numbers 57—71), are members of Group IIIA in the periodic table (Fig. 1.1) and all have...fractionation in a rock or mineral can be a pointer 1 Group H 3 1Li Na VIIIB 2 HA MB 5 Be 12 Mg IIIA...42 43 73 74 58 90 23 4 V Nb Ta Ce Th Group VIII 27 28 44 45 75 76 77 59 60 61 91...accurate quantitative analysis for the REE, both as a group and individually, is now possible on a routine basis |  | Kogel, Jessica Elzea, Trivedi, Nikhil C., Barker, James M., Krukowski, Stanley T. - Eds. (2006) Industrial Minerals and Rocks (7th ed.) Society for Mining, Metallurgy, and Exploration, Inc., Littleton, CO. | Book (edition) | | . . . . . . . . . . . . . . . . . . . . . . . . Mine Safety and Health Law . . . . . . . . . . . . ....can depend on for many years, an international group of volunteer authors, coauthors, and associate editors—all...least one peer re view. Finally, an outstanding group of professional copy editors, proofreaders, graphi...Research and Development Ltd. Israel Chemicals Group Haifa Bay, Israel Tadataka Hida Shokozan Mining...Electronic edition published 2009. Vincent G. Hill Stanley T. Krukowski Retired Mandeville, Jamaica |
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