Extreme F activities in late Pegmatitic events as a key factor for lile and HFSE enrichment: The Angel Pegmatite, Central Argentina
| Autor: | Manuel Demartis, Fernando Colombo, Pura Alfonso, Lucio Pedro Pinotti, Jorge E. Coniglio, Fernando Javier D'eramo, Joan Carles Melgarejo |
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| Přispěvatelé: | Universitat de Barcelona |
| Rok vydání: | 2014 |
| Předmět: |
MINA ANGEL
ARGENTINA Microcline Mineral Metasomatisme (Mineralogia) biology Muscovite Geochemistry engineering.material LILE AND HFSE ENRICHMENT biology.organism_classification Ciencias de la Tierra y relacionadas con el Medio Ambiente Topaz Geochemistry and Petrology Metasomatism (Mineralogy) Pollucite LATE METASOMATIC REPLACEMENT EVENTS engineering Elbaite Meteorología y Ciencias Atmosféricas Geology Pegmatite Lile EXTREME F ACTIVITIES CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | Dipòsit Digital de la UB Universidad de Barcelona Recercat. Dipósit de la Recerca de Catalunya instname |
| Popis: | The Ángel pegmatite forms part of the Comechingones pegmatitic field, in central Argentina, which is made up of pegmatites characterized by low to intermediate degrees of fractionation, classified as beryl-columbite-phosphate subtype pegmatites. These pegmatites are syntectonic with a regional shear zone. The Ángel pegmatite contains associations with quartz, microcline, plagioclase, a first generation of muscovite (muscovite I), beryl, members of the columbite group, triplite, and montebrasite. This association is locally affected by two stages of replacement. The first replacement stage is characterized by early albitization, followed by the development of associations of cleavelandite, quartz, Fe-rich elbaite (elbaite I), a second generation of muscovite (muscovite II), topaz, lacroixite, fluorapatite, pollucite, columbite-(Mn), and Hf-rich zircon. Muscovite II replaces montebrasite and muscovite I, and is characterized by slight enrichments in F, Rb, and Cs. The second replacement stage generated a new mineral association characterized by muscovite III, Fe-poor elbaite (elbaite II), Cs-micas, and U-rich hydroxykenomicrolite. Muscovite III replaces muscovite II and is characterized by strong enrichments in F, Cs, and, to a lesser extent, Rb. In turn, muscovite III is replaced by the Cs-micas sokolovaite and nanpingite. The high F content of the nanpingite suggests that this could be the F- analogue of nanpingite, which would be a new mineral. The sequence of replacement is indicative of an increase in the F activity in the latest pegmatitic fluids. The high F activity of these fluids favored the transport of Ta, U, Bi, Hf, Rb, Cs, and Li, and the formation of F-rich micas could be the mechanism for precipitating these LILE and HFSE elements. The syntectonic emplacement of this pegmatite in a large shear zone could be a decisive factor in the migration of these late evolved fluids rich in F, LILE, and HFSE. Fil: Demartis, Manuel. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Melgarejo, Joan Carles. Universitat Autònoma de Barcelona; España Fil: Colombo, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geologia Básica y Aplicada; Argentina Fil: Alfonso, Pura. Universitat Autònoma de Barcelona; España Fil: Coniglio, Jorge Enrique. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; Argentina Fil: Pinotti, Lucio Pedro. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: D'eramo, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; Argentina |
| Databáze: | OpenAIRE |
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