A note on the occurrence of niobian zirconolite, pyrochlore and baddeleyite from the Kovdor carbonatite complex
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 baddele...
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| Format: | Text |
| Language: | English |
| Published: |
1996
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| 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 |
| Summary: | 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. |
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