| Title | Uraninite geochemistry in the Central Mineral Belt, Labrador, Canada |
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| Author | Acosta-Góngora, P; Potter, E ; Lawley, C; Petts, D; Sparkes, G |
| Source | NGF abstracts and proceedings of the Geological Society of Norway: Vinterkonferansen 2021; by Nakrem, H A (ed.); Husås, A M (ed.); 2021 p. 2  Open Access |
| Links | Online - En
direct (complete volume - volume complet, PDF, 2.52 MB)
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| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210208 |
| Publisher | Norsk Geologisk Forening |
| Meeting | Norsk Geologisk Forening, Vinterkonferansen 2021 - Geological Society of Norway, 34th Geological Winter Meeting; January 6-8, 2021 |
| Document | book |
| Lang. | English |
| Media | digital; on-line |
| File format | pdf |
| Province | Newfoundland and Labrador |
| NTS | 13J; 13K; 13L; 13M; 13N; 13O |
| Area | Labrador; Jacques Lake; Moran Lake; Anna Lake; Snegamook Lake; Kanairiktok River |
| Lat/Long WENS | -62.7000 -58.9500 55.3833 54.0500 |
| Subjects | economic geology; geochemistry; Science and Technology; Nature and Environment; mineral deposits; uranium; base metals; precious metals; uraninite; ore mineral genesis; mineralization; host rocks;
statistical analyses; trace element geochemistry; thermal analyses; magmatism; hydrothermal systems; metasomatism; alteration; Central Mineral Belt; Dandy Prospect; Near Miss Prospect; Jacques Lake Deposit; Precambrian; Proterozoic |
| Program | Targeted Geoscience Initiative (TGI-5) Uranium ore systems - deep metasomatic processes |
| Released | 2021 01 01 |
| Abstract | The Central Mineral Belt (CMB) of Labrador in Canada is host to several enigmatic Proterozoic U±base±precious metal showings, prospects and deposits that have disparate features in terms of their
mineralization styles (e.g., vein and breccia-hosted, disseminated) and host rocks (metasedimentary, - volcanic and -intrusive). Through multivariate statistical analysis (principal component and cluster analyses), quantitative trace element maps of
uraninite grains were used to understand the origins of U mineralization from selected locations across the CMB.
Chemical signatures of uraninite from the felsic intrusion- and intermediate volcanic-hosted Dandy prospect (negative Eu anomaly, U/Th
< 1000 and sigma-LREE/sigma-HREE= 3) and Near Miss prospect (Near Miss 1; U/Th > 1000 and sigma-REE > 1 wt.%) and Jacques Lake deposit (U/Th < 1000 and sigma-REE almost equal to 1 wt.%), respectively, support formation under high temperature
magmatic-hydrothermal or metasomatic environments. However, post-crystallization alteration caused LREE enrichment and increased U/Th values in uraninite. Lower temperature (<350 °C) hydrothermal vein-type conditions are inferred for uraninite
samples from the Two-Time deposit (Two-Time 1 to 3), and Anomaly No. 7 (Anomaly No. 7 1 to 4) and Near Miss (Near Miss 2) prospects based on high U/Th values (>> 1000), elevated sigma-LREE/sigma-HREE ratios (> 14) and variable sigma-REE contents
(from < 1 wt.% to >1 wt.%). Trace element mapping of uraninite from the Anomaly No. 7 revealed concentric multi-elemental (e.g., Zr, Bi, V, Hf) zoning representing four uraninite generations that formed under relatively equivalent hydrothermal
conditions (analogous sigma-LREE/sigma-HREE and U/Th values). The more ambiguous chemical footprints and complex textural features of the metasedimentary-hosted uraninite from the Moran Lake Upper C Zone, Nash and Anna Lake deposits (U/Th >> 1000),
sigma-REE << 1 wt.% and sigma-LREE/sigma-HREE < 5) indicate formation by syn- to post-metamorphic, high salinity and low temperature hydrothermal fluids.
Overall, this study reveals the presence of distinct U mineralizing events and fluid sources,
driven by syn- to post-mineralization orogenic and magmatic events. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI) is a collaborative federal geoscience program that provides industry with the next generation of geoscience
knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This contribution summarizes the chemical composition of the ore mineral uraninite from several mineral occurrences from
the Central Mineral Belt in Labrador. The contrasting chemical signatures of uraninite indicate the deposits formed by several processes and do not represent a single ore-forming event. |
| GEOSCAN ID | 328698 |
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