Pirofanita y Braunita titánica en las rocas con Mn del Sector Central de Ossa-Morena.
- J. Jiménez Millán 1
- N. Velilla 2
- 1 Departamento de Geología.Universidad de Jaén.
- 2 Departamento de Mineralogía y Petrología. Universidad de Granada.
ISSN: 0213-683X
Ano de publicación: 1996
Número: 20
Páxinas: 1542-1545
Tipo: Artigo
Outras publicacións en: Geogaceta
Resumo
In the Oliva de la Frontera area (Ossa-Morena Central Belt, lberian Massif, SW Spain) titanian braunite occurs in manganiferous metashales and manganiferous metatuffs while pyrophanite is restricted to pyroxmangite metatuffs. During hercynian metamorphism primary Mn4+ was reduced to Mn3+ and Mn2+ to form piemontite in shales and metatuffs, and more extensively in piroxmangite metatuffs to form pyrophanite. Ti and Al-enrichment in braunite depend on the whole composition while high Fecontent in braunite of piroxmangite metatuffs can be related to low fO2 conditions.