A note on the occurrence of niobian zirconolite, pyrochlore and baddeleyite from the Kovdor carbonatite complex

• Main Author: C. Terry Williams
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: zirconolite; baddeleyite; pyrochlore; carbonatites; Kola Peninsula; Russia; Kovdor; kola peninsula
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.611.281; http://www.minersoc.org/pages/Archive-MM/Volume_60/60-401-639.pdf

The compositions and textural relationships of the oxide minerals zirconolite, pyrochlore and baddeleyite are described. These occur as accessory minerals, often intergrown with each other, from a phoscorite " rock associated with the Kovdor carbonatite complex. Both the zirconolite and baddeleyite have relatively high concentrations of Nb and Ta; the pyrochlore is rich in U and Ta. Backscattered lectron images, coupled with detailed microprobe analyses, reveal complex compositional zoning in zirconolite and pyrochlore which reflect changes in the fluid composition during growth of these minerals. A comparison is made of incompatible dement ratios Zr/Hf, Nb/Ta and Th/U between the three accessory minerals.