| Reference Type | Journal (article/letter/editorial) |
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| Title | Non-metamict uranoan pyrochlore and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda |
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| Journal | Mineralogical Magazine | ISSN | 0026-461X |
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| Authors | Hogarth, D. D. | Author |
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| Horne, J. E. T. | Author |
| Year | 1989 (April) | Volume | 53 |
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| Page(s) | 257-262 | Issue | 370 |
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| Publisher | Mineralogical Society |
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| Download URL | https://rruff.info/doclib/MinMag/Volume_53/53-370-257.pdf+ |
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| DOI | doi:10.1180/minmag.1989.053.370.14Search in ResearchGate |
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| Mindat Ref. ID | 1500 | Long-form Identifier | mindat:1:5:1500:8 |
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| GUID | 5996af08-c76b-4ed3-8ca8-f0183b314bba |
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| Full Reference | Hogarth, D. D., Horne, J. E. T. (1989) Non-metamict uranoan pyrochlore and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda. Mineralogical Magazine, 53 (370) 257-262 doi:10.1180/minmag.1989.053.370.14 |
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| Plain Text | Hogarth, D. D., Horne, J. E. T. (1989) Non-metamict uranoan pyrochlore and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda. Mineralogical Magazine, 53 (370) 257-262 doi:10.1180/minmag.1989.053.370.14 |
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| In | (1989, April) Mineralogical Magazine Vol. 53 (370) Mineralogical Society |
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| Abstract/Notes | AbstractA thin (100 m) cover of flat-lying, Recent, calcite-rich tuff at Ndale near Fort Portal, Uganda, unconformably overlies steeply dipping Precambrian metamorphic rocks. It is locally radioactive owing to uranium-rich pyrochlore minerals and lesser amounts of zircon, monazite, titanite, and an unidentified thorium phosphate. In one concentrate, four grains of uranpyrochlore and one grain of uranoan pyrochlore showed a positive linear correlation of Ti with U, and negative linear correlations of Ti with Na, F and Sr. Ta remained high and relatively constant [11 anal., ave. 14.5 (0.6)% Ta2O5]. In the same concentrate the composition of a separate grain of uranoan pyrochlore did not plot on these lines and Ta was comparatively low [2 anal., ave. 4.5 (0.3)% Ta2O5]. The data suggest two separate paths of differentiation. However, zoned grains were not observed. Unit cells were cubic with a = 10.351 ± 0.002 Å for a grain with 12.9% UO2tot and 10.333 ± 0.002 Å for a grain with 26.6% UO2tot. On heating in air the cell size decreased, possibly due to oxidation of U4+. The crystalline nature of these minerals can be attributed to a very young (4000–5000 yr) geological age. |
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