Baldwin, Joy R. (1989) Replacement phenomena in tantalum minerals from rare-metal pegmatites in South Africa and Namibia. Mineralogical Magazine, 53 (373) 571-581 doi:10.1180/minmag.1989.053.373.08
| Reference Type | Journal (article/letter/editorial) | ||
|---|---|---|---|
| Title | Replacement phenomena in tantalum minerals from rare-metal pegmatites in South Africa and Namibia | ||
| Journal | Mineralogical Magazine | ISSN | 0026-461X |
| Authors | Baldwin, Joy R. | Author | |
| Year | 1989 (December) | Volume | 53 |
| Issue | 373 | ||
| Publisher | Mineralogical Society | ||
| Download URL | https://rruff.info/doclib/MinMag/Volume_53/53-373-571.pdf+ | ||
| DOI | doi:10.1180/minmag.1989.053.373.08Search in ResearchGate | ||
| Generate Citation Formats | |||
| Mindat Ref. ID | 1552 | Long-form Identifier | mindat:1:5:1552:7 |
| GUID | 0 | ||
| Full Reference | Baldwin, Joy R. (1989) Replacement phenomena in tantalum minerals from rare-metal pegmatites in South Africa and Namibia. Mineralogical Magazine, 53 (373) 571-581 doi:10.1180/minmag.1989.053.373.08 | ||
| Plain Text | Baldwin, Joy R. (1989) Replacement phenomena in tantalum minerals from rare-metal pegmatites in South Africa and Namibia. Mineralogical Magazine, 53 (373) 571-581 doi:10.1180/minmag.1989.053.373.08 | ||
| In | (1989, December) Mineralogical Magazine Vol. 53 (373) Mineralogical Society | ||
| Abstract/Notes | AbstractManganotantalite replacement by (1) microlite and (2) ferrotantalite, and changes in composition of uranoan microlite from rare-metal pegmatites in South Africa and Namibia have been investigated with the electron microprobe. A uranmicrolite from Karibib, Namibia contained 14.35% UO2, 1.03% PbO, 56.12% Ta2O5, 13.18% Nb2O5, 0.58% Fe2O3, 6.87% CaO, 0.54% SrO, 0.59% MnO, 0.86% Na2O and 0.47% F. Analyses along traverses across a 1.3 mm uranoan microlite, Tantalite Valley, Namibia, revealed two essentially distinct compositions: a more hydrated rim area of 200 µm radius containing 7% higher Ta2O5, 10% lower CaO and 1.3% lower F than a main central area of slightly variable composition. Back-scattered electron images reveal zoning and distinctive subspheroidal structures. New data and structural features are given for radioactive uranoan microlite from Namaqualand, South Africa. These crystals contain remnants of a bismuth phase and are in various stages of replacement. In the microlites replacing manganotantalite, the microlite reflects the composition of the replaced mineral. At Rubicon Mine, Karibib, a narrow marginal zone of mangantantalite is replaced by ferrotantalite along cleavages; a zone of intermediate composition is apparent. Detailed traverses have been completed across all of these crystals. | ||
Map of Localities
Locality Pages
| Locality | Citation Details |
|---|---|
| Homestead pegmatite, Tantalite Valley, Karasburg East, ǁKaras Region, Namibia | |
| Lepidolite pegmatite, Tantalite Valley, Karasburg East, ǁKaras Region, Namibia |
Mineral Pages
| Mineral | Citation Details |
|---|---|
| Uranmicrolite (of Hogarth 1977) | [as uranoan microlite] |
Mineral Occurrences
See Also
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