Sabiia Seb
        Busca avançada

Botão Atualizar

Botão Atualizar

Registro completo
Provedor de dados:  Anais da ABC (AABC)
País:  Brazil
Título:  Mineral chemistry of tantalate species new in the Borborema Pegmatitic Province, Northeast Brazil
Autores:  Beurlen,Hartmut
Soares,Dwight R.
Prado-Borges,Lucila E.
Castro,Cláudio de
Data:  2005-03-01
Ano:  2005
Palavras-chave:  Titanian ixiolite
Northeast Brazil
Resumo:  Tantalate samples, supposedly of the columbite group, were collected in the Borborema Pegmatitic Province, aiming to test the Mn/(Mn+Fe) and Ta/(Ta+Nb) ratios as geochemical indicators of pegmatite fractionation. Surprisingly, preliminary microprobe data allowed recognizing some species, so far unknown in the Province, namely titanian ixiolite, fersmite, brannerite, strüverite, natrobistantite, plumbo- and stibiomicrolite, plumboand uranpyrochlore. The identification of these exotic tantalates with unusual composition, in addition to its distribution in several pegmatites, far from the classical Alto do Giz and Seridozinho pegmatites, indicate that the elevated degree of fractionation is not restricted to these two occurrences but may be reached in other pegmatite areas of the Province. It indicates also that this degree of fractionation may be very variable between pegmatites in small areas. The zoning patterns observed in the titanian ixiolite, with Ti and Nb enrichment at the borders at expense of Ta enriched in the core, are also quite unusual and reverse in comparison with the normal trend of progressive Ta and Mn enrichment in tantalates with the degree of fractionation. A similar "reverse" trend was observed in titanian wodginite of petalite/pollucite bearing pegmatites of the Separation Rapids Province in Ontario, Canada.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Editor:  Academia Brasileira de Ciências
Relação:  10.1590/S0001-37652005000100013
Formato:  text/html
Fonte:  Anais da Academia Brasileira de Ciências v.77 n.1 2005
Direitos:  info:eu-repo/semantics/openAccess

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC:

Valid HTML 4.01 Transitional