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Composition of priderite in phlogopitites from the Catalão I carbonatite complex, Brazil

Published online by Cambridge University Press:  05 July 2018

José C. Gaspar ,
Antônio J. G. Conceição e Silva  and
Débora P. de Araújo
José C. Gaspar
Affiliation:
Departamento de Mineralogia e Petrologia, Instituto de Geociências, Universidade de Brasília, 70910-900 Brasilia D.F., Brazil
Antônio J. G. Conceição e Silva
Affiliation:
Departamento de Mineralogia e Petrologia, Instituto de Geociências, Universidade de Brasília, 70910-900 Brasilia D.F., Brazil
Débora P. de Araújo
Affiliation:
Departamento de Mineralogia e Petrologia, Instituto de Geociências, Universidade de Brasília, 70910-900 Brasilia D.F., Brazil
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Abstract

Magnetite grains with exsolved ilmenite lamellae may be replaced by pyrite or carbonate in phlogopitites of the Catalão I carbonatite complex, Goiás State, Brazil. The ilmenite is transformed in part to priderite and sometimes to rutile. Priderite occurs as small anhedral grains (< 0.2mm) or composite crystals associated with ilmenite and rutile. Chalcopyrite, magnetite, monazite, and pyrochlore also occur inside the area of original magnetite grains. The priderite belongs to the K2FeTi7O16-BaFeTi7O16 series with K/(K + Ba) ranging from 1.0 to 0.53. The highest contents for other elements are: V2O3 2.65, Cr2O3 4.1, and Nb2O5 1.98 wt.%. Priderites associated with magnetite have the highest V, Cr, and Nb contents whereas others have the highest Ba content. Zoning characterized by K-Ba substitution is patchy but always present. V-and Cr-poor priderites are similar in composition to priderites from lamproites, and the V- and Cr-rich ones are compositionally similar to hollandite-group minerals found in kimberlites.

Keywords

prideritecarbonatitephlogopiteilmeniteBrazil
Type
Mineralogy
Information
Mineralogical Magazine , Volume 58 , Issue 392 , September 1994 , pp. 409 - 415
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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