 | 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) | | and rare earth minerals from the Virulundo carbonatite, Namibe, Angola L. TORRÓ1, C. VILLANOVA1, M. CASTILLO1...Agostinho Neto, Av. 4 de Fevereiro 7, 815 Luanda, Angola [Received 27 January 2011; Accepted 7 July 2011;... The Virulundo carbonatite in Angola is one of the largest in the world and contains pyrochlore as an...breccias and trachytoids). The primary magmatic pyrochlore is fluorine dominant and typically contains about...replacement of the primary pyrochlore by a second generation of pyrochlore with less F and Na. Low-temperature |  | Amores-Casals, , Melgarejo, , Bambi, , Gonçalves, , Morais, , Manuel, , Neto, , Costanzo, , Molist, (2019) Lamprophyre-Carbonatite Magma Mingling and Subsolidus Processes as Key Controls on Critical Element Concentration in Carbonatites—The Bonga Complex (Angola) Minerals, 9 (10) 601 doi:10.3390/min9100601 | Journal (article/letter/editorial) | | Concentration in Carbonatites—The Bonga Complex (Angola) Sandra Amores-Casals 1,2, *, Joan-Carles Melgarejo...Universidade Agostinho Neto, Luanda, Caixa Postal 815, Angola; aurorabambi@hotmail.com (A.B.); tonygoncalves72@hotmail...reconstruct the dynamics of the complex, the pyrochlore composition and distribution have been used as...evolution of the complex. An early Na-, F-rich pyrochlore is disseminated throughout the carbonatite plug...dykes. Crystal accumulation led to enrichment of pyrochlore crystals in the plug margins, phoscoritic units |  | 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) | | species in plutonic carbonatites: The Tchivira case, Angola Joan C. Melgarejo a, Alessandra Costanzo b,⁎, Aurora...Geologia, Universidade Agostinho Neto, Luanda, Angola a r t i c l e i n f o Article history: Received...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 |  | | Journal (article/letter/editorial) | | Monte Verde Carbonatite–Alkaline–Agpaitic Complex (Angola) Sandra Amores-Casals 1,2, *, Antonio Olimpio Gonçalves...Universidade Agostinho Neto, Luanda, Caixa Postal 815, Angola; tonygoncalves72@hotmail.com Institut de Ciències...rare earth elements (REE) are concentrated in pyrochlore crystals in the carbonatite and alkaline breccias...and overgrown by five secondary generations of pyrochlore formed during subsolidus stages and have higher...and Ti contents. The second, third, and fourth pyrochlore generations are associated with late fluids also |  | | Journal (article/letter/editorial) | | 377–392 Tracing the chemical evolution of primary pyrochlore from plutonic to volcanic carbonatites: the role...Agostinho Neto, Av. 4 de Fevereiro 7, 815 Luanda, Angola Earth and Ocean Sciences, School of Natural Sciences...carbonatites are volcanic in origin. In Tchivira pyrochlore, zoning is poorly developed; fluorine is dominant...volcanic carbonatites. K EY WORDS : Angola, carbonatite, zonation in pyrochlore, fluorine, high field strength...strength elements, HFSE, pyrochlore, rare earth elements, REE, mineral zonation. Introduction CARBONATITES and |  | | Journal (article/letter/editorial) | | melt solution calorimetry, heat of formation, pyrochlore, defect fluorite, rare earth minerals Introduction...(heavy rare earths, Gd–Lu) (Linnen et al. 2014). Pyrochlore and zircon account for over 90% of the Nb and...NIOBATES, RE3NbO7 1579 magnetic behavior. The same group reported that the lanthanide element also influences...the fluorite Fm3m structure, microdomains of pyrochlore phase (Fd3m) can be found, suggesting considerable...smaller RE is consistent with findings that this group belongs to the intrinsically disordered defect fluorite |  | Starikova, Anastasia E., Bazarova, Ekaterina P., Savel’eva, Valentina B., Sklyarov, Eugene V., Khromova, Elena A., Kanakin, Sergei V. (2019) Pyrochlore-Group Minerals in the Granite-Hosted Katugin Rare-Metal Deposit, Transbaikalia, Russia. Minerals, 9 (8) 490 doi:10.3390/min9080490 | Journal (article/letter/editorial) | | minerals Article Pyrochlore-Group Minerals in the Granite-Hosted Katugin Rare-Metal Deposit, Transbaikalia...August 2019 Abstract: Pyrochlore group minerals are the main raw phases in granitic...%), ThO2 (to 1.8 wt.%), and PbO (to 1.4 wt.%). Pyrochlore of this type is very rare in nature and is limited...columbite. Secondary-I pyrochlore follows cracks or replaces primary pyrochlore in grain rims and is compositionally...complete A- and Y-sites occupancy. Secondary-II pyrochlore is a product of late hydrothermal alteration |  | | Journal (article/letter/editorial) | | -polymorphs (anatase, brookite and rutile) and three pyrochlore group members (hydroxycalcio-, fluorcalcio-, and...in the Petyayan-Vara) and minerals of the pyrochlore group. This process also caused niobium enrichment...elements. Keywords: metasomatism; brookite; anatase; pyrochlore; niobium; carbonatites; Vuoriyarvi massif 1...niobium concentrators are minerals of the pyrochlore group and, less frequently, the perovskite, columbite...which is much higher than in the largest known pyrochlore deposit. Hypergenesis certainly played a crucial |  | | 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 |  | Zozulya, Dmitry, Lyalina, Lyudmila, Macdonald, Ray, Bagiński, Bogusław, Savchenko, Yevgeny, Jokubauskas, Petras (2019) Britholite Group Minerals from REE-Rich Lithologies of Keivy Alkali Granite—Nepheline Syenite Complex, Kola Peninsula, NW Russia. Minerals, 9 (12) 732 doi:10.3390/min9120732 | Journal (article/letter/editorial) | | minerals Article Britholite Group Minerals from REE-Rich Lithologies of Keivy Alkali Granite—Nepheline...of economic importance) and diverse britholite group minerals. The REE and actinides distribution in...crystallization of fluorbritholite-(Ce). Britholite group minerals (mainly fluorcalciobritholite and ‘calciobritholite’)...up to theoretical apatite. Keywords: britholite group minerals; alkali granite; nepheline syenite; pegmatite;...Peninsula; Russia 1. Introduction The britholite group contains relatively common accessory minerals that |  | | Journal (article/letter/editorial) | | 1007/s00710-017-0493-3 ORIGINAL PAPER Britholite-group minerals as sensitive indicators of changing fluid...pegmatite formation: evidence from the Keivy alkaline province, Kola peninsula, NW Russia Dmitry R. Zozulya 1...Springer-Verlag Wien 2017 Abstract The Keivy alkaline province, Kola Peninsula, NW Russia, consists of vast alkali...contains a remarkably diverse number of britholite group minerals, pointing to different physico-chemical...CO2. From REE and F variations of the britholite group minerals possible fluid compositions at different |  | Giebel, R. Johannes, Gauert, Christoph D.K., Marks, Michael A.W., Costin, Gelu, Markl, Gregor (2017) Multi-stage formation of REE minerals in the Palabora Carbonatite Complex, South Africa. American Mineralogist, 102 (6) 1218-1233 doi:10.2138/am-2017-6004 | Journal (article/letter/editorial) | | Ce-enriched, Nd-dominated end-member of this mineral group and is very rare compared to all other REE minerals...zirconolite (Figs. 8a and 8b). REE-Ti-betafite (pyrochlore-group member). The REETi-oxide REE-Ti-betafite (alternatively...represents the most important Nb-phase in the system (pyrochlore sensu stricto is lacking), but its very low abundance...low-temperature phase in the Virulando carbonatite (Angola) where it formed during late-stage supergene alteration...to mine: the key example of the Kola Alkaline Province, Mineralogical Society (U.K.) Series, 10, 247–291 |  | Sun, Zhenghao, Qin, Kezhang, Mao, Yajing, Tang, Dongmei, Wang, Fangyue, Evans, Noreen J., Zhou, Qifeng (2022) Mineral Chemistry of Pyrochlore Supergroup Minerals from the Boziguoer Nb-Ta-Zr-Rb-REE Deposit, NW China: Implications for Nb Enrichment by Alkaline Magma Differentiation. Minerals, 12 (7) 785 doi:10.3390/min12070785 | Journal (article/letter/editorial) | | minerals Article Mineral Chemistry of Pyrochlore Supergroup Minerals from the Boziguoer Nb-Ta-Zr-Rb-REE...; Evans, N.J.; Zhou, Q. Mineral Chemistry of Pyrochlore Supergroup Minerals from the Boziguoer Nb-Ta-Zr-Rb-REE...aegirine). The Nb in the deposit is mainly hosted in pyrochlore supergroup minerals, ubiquitous in alkalic granite...in the A-site further classifies the Boziguoer pyrochlore supergroup minerals as fluornatropyrochlore,...fluorcalciopyrochlore and fluorkenopyrochlore. All Boziguoer pyrochlore supergroup minerals are Nb-rich and Ta-poor at |  | Nedosekova, Irina, Vladykin, Nikolay, Udoratina, Oksana, Belyatsky, Boris (2021) Ore and Geochemical Specialization and Substance Sources of the Ural and Timan Carbonatite Complexes (Russia): Insights from Trace Element, Rb–Sr, and Sm–Nd Isotope Data. Minerals, 11 (7) 711 doi:10.3390/min11070711 | Journal (article/letter/editorial) | | signatures and ore specialization: Nb-deposits of pyrochlore carbonatites are associated with the IVC, while...moderately depleted mantle source for rocks and pyrochlore mineralization. The Buldym complex has a higher...carbonatites; Sr–Nd isotopes; Nb–REE deposits; pyrochlore; bastnäsite; Urals; Timan Received: 28 May 2021...production of rare earth elements of the cerium group. Carbonatites are usually cogenetic with alkaline...Siberia—White Winter, Middle Winter (East Sayan province); the Nb–REE Chuktukonskoe deposit (Chadobetsky |  | 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 (article/letter/editorial) | | macrocrysts or phenocrysts of Fe-Ti-rich spinel-group minerals, ferromagnesian silicates and apatite (Tappe...previous Figs.). a Early precipitation of calcite, pyrochlore (Pcl) and apatite (Ap) in carbonatite evolving...inclusion studies indicate that primary burbankite-group phases, norsethite [BaMg(CO3)2] and bradleyite [Na3Mg(PO4)(CO3)]...Cumulate aggregate of apatite, diopside (Di), pyrochlore and calcite; Firesand River, Canada (SB 0.5 mm)...zircon and titanite), or oxides (major magnetite, pyrochlore, perovskite or ferrocolumbite with accessory |  | | Journal (volume) | | .............................245 EG52 Platinum-group minerals in the new millennium....................[1]. Chromium-rich spinels MCr2O4 are part of a group of exciting and challenging materials that have...materials. They were studied by J.E. Shelby’s research group in Alfred University, New York, USA, according to...(2009) Appl. Clay. Sci., 43, 224-227. Apatite group minerals and their secondary alteration phases were...probably similar to that known in the nagelschmidtite group or as berlinite substitution in silicates. The determination |
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