| Abstract: | Uranium in the Ekiek Creek Complex of western Alaska is related to a niobium-rich pyrochlore in the nepheline syenite of the complex. The complex consists of an aegirine-phlogopite pyroxenite that has been intruded and partly replaced by nepheline syenite. The contact zone between the two igneous units varies from a sharp contact to a diffuse zone where the pyroxenite has been metasomatically replaced by the syenite. The entire complex was intruded into an older Cretaceous monzonite.
The pyrochlore occurs as an accessory mineral in the syenite, and is visible in rocks containing over 50 ppm uranium. Chemical analyses indicate that, in all samples of syenite, there is a positive correlation between uranium and niobium; this suggests that the uranium-pyrochlore association persists even when pyrochlore is not readily visible in thin section. The small amount of pyrochlore, and its refractory nature, make the complex an unfavorable source for secondary uranium leaching or heavy-mineral concentration. |
| Genre: | USGS Numbered Series |
| ProdID: | 11554 |
| Citation Author: | Wallace, Alan R. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | ii, 23 p. ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 79-1653 |
| Citation Search Results Text: | Occurrence of uranium in rocks of the intrusive complex at Ekiek Creek, western Alaska; 1979; OFR; 79-1653; Wallace, Alan R. |
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| Citation Year: | 1979 |
| Type: | citation/reference |
| Text: | Occurrence of uranium in rocks of the intrusive complex at Ekiek Creek, western Alaska; 1979; OFR; 79-1653; Wallace, Alan R. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/of/1979/1653/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/of/1979/1653/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
