Guardado en:
| Autor principal: | |
|---|---|
| Formato: | Artículo científico |
| Lenguaje: | en |
| Publicado: |
Academia Brasileira de Ciências
2007
|
| Materias: | |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=32779307 |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
Tabla de Contenidos:
- Chemical zoning of muscovite megacrystal from the Brazilian Pegmatite Province Rúbia R. Viana Hanna J. Evangelista Willem B. Stern Multidisciplinaria (Ciencias Naturales y Exactas) muscovite chemical zoning Cruzeiro pegmatite hydrothermal alteration Macroscopically homogenous muscovite plate from the Cruzeiro pegmatite, located in the Eastern Pegmatite Provincein Minas Gerais, may show complex distribution patterns of some trace elements. In geochronological and petrologicalstudies, as for example in the distinction of magmatic and post-magmatic mica, the cause of zoning could be takeninto consideration. The complex chemical zoning in the studied mica plate can be best explained by growth in anevolving magma followed by alteration due to percolation of hydrothermal fluids. Enrichment of Rb towards the borderis interpreted as resulting from the chemical evolution of the residual magma during crystal growth. The depletion in(IVAl+VIAl) as well as the increase in (Fe+Mg) and Si along a fracture could be due to the hydrothermal celadoniticsubstitution of muscovite. This alteration also caused depletion in the contents of Rb, Ga, Y, Nb, Sn, and Zn and residualconcentration of Ti. Elements such as Ga, Y, Nb, Sn, and Zn, rarely considered in the discussion of differentiation oralteration processes in micas, have been shown to be as significant as the alkali-elements. 2007 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32779307 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.79